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The Bulletin ofThe Canadian Associationof Physicists

Vol. 39 No. 3 Congress Issue 1983

Physics in Canada

Bulletin del’Association canadienne des physiciens

Vol. 39 N° 3Numéro du Congrès 1983

La Physique au Canada

EDITORIAL BOARD/COMITÉ DE RÉDACTIONEditor/Réacteur en chefJ. RolfeBank of Canada, 234 Wellington St., Ottawa, Ontario KIA 0G9 (613) 563-8906 TABLE OF CONTENTS/SOMMAIREAssociate Editor/Rédacteur AssociéM.L. JentoManaging/Administration

Book Review Editor/Rédacteur à la critique des livresJ.P. SvenneDept, of Physics, University of Manitoba,Winnipeg, Manitoba R3T 2N2 (204) 474-9856

Laurent G. CaronDépartement de physique. Université de Sherbrooke, Sherbrooke, Québec JIK 2RI (819) 565-3587

R. Fraser CodePhysics Department, University of Toronto,Erindale Coll R 4039, MISSISSAUGA, Ontario I.5L IC6 (416) 828-5353

G.A. DaigleConseil national de recherches du Canada, Div. de physique, Ottawa, Ont.(613) 993-2840

Elmer H. HaraDepartment of Communications,Room 1648, Journal Tower North,300 Slater Street, Ottawa KIA 0C8 (613) 593-6460

Officers of the Association 2Corporate Members/Membres Corporatifs 21983 Congress, General Information 3Congrès 1983, Renseignements généraux 3Maps/Plans 6, 7, 8CAP Medallists 1983/Lauréats de l'ACP 1983 9CAP Prize Exam 1983/Examen de l’ACP 1983 9Exhibitors/Exposants 9Invited Speakers/Conférenciers invités 10Instructions for Timed Papers 11Program Summary/Résumé du programme 12Congress Program/Programme du Congrès 14Forms/Eormules CentreAuthor index/Index des auteurs 70

Front Cover:

The University of Victoria Campus from the southeast. The Elliott building is to the left of centre and has a telescope dome on the roof. The University residences are in the foreground at the right.

John A. NilsonLumonics Inc.105 Schneider Rd., ΚΑΝΑΤΑ (Ottawa), Ont. K2K IY3 (613) 592-1460

R.R. ParsonsPhysics Department. University of British Columbia Vancouver, B.C. V6T IW5 (604) 228-2929

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Veuillez apporter cet exemplaire gratuit du programme au Congrès à Victoria. Des exemplaires supplémentaires se vendront à $3.00 chacun.

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®Canadian Association o f Physicists/Association canadienne des physiciens 19HÍ. AH rights reservedSecond Class Mail Registration Number: 5415 ISSN 0031-9147

Officers of the Association/Bureau de direction

COUNCIL/CONSEIL 1982-83President: A.R. Crawford*, Anatek Electronics Limited Past President: P. Marmet*, Université Laval Vice-President: B.P. Stoicheff*, University o f Toronto Vice-President Elect: G.C. Hanna*, Atomic Energy o f Canada Honorary Secretary-Treasurer: B.C. Gregory*, l.N.R.S. — Univer­

sité du QuébecDirector — Members: W.R. Datars, McMaster University Director — Affiliates: T.W.R. East, Raytheon Canada Limited Director — Student Members: G. Crawford, University o f Victoria Director — Corporate Members: A.I. Carswell, York University

Division ChairmenAeronomy & Space Physics: J.A. Koehler, University of

SaskatchewanAtomic & Molecular Physics: E.J. Knystautas, Université Laval Canadian Geophysical Union: M.J. Keen, Geological Survey of

CanadaCondensed Matter Physics: G. Dolling, Chalk River Nuclear Labs Medical & Biological Physics: K.E. Breitman, Manitoba Cancer

FoundationNuclear Physics: R.J. Slobodrian, Université Laval Optical Physics: R.W. Nicholls, York University Particle Physics: R. Migneron, University o f Western Ontario Physics Education: W. Brouwer, University o f Alberta Plasma Physics: B. Ahlborn, University o f British Columbia Theoretical Physics: W.J.L. Buyers, Atomic Energy of Canada Industrial & Applied Physics: J-P. Monchalin Surface Science: J.D. Carette, Université Laval

‘ Member of Executive Committee(I) Term ends June 1983 (2) Term ends June 1984

Councillors/ConseillersBritish Columbia and Yukon

C.F. Schwerdtfeger, University of British Columbia (1) R.M. Clements, University o f Victoria (2)

AlbertaE.H. Pinnington, University o f Alberta (1)C.D. Anger, University of Calgary (2)

Saskatchewan and ManitobaE.J. Ansaldo, University o f Saskatchewan (1)K. G. Standing, University of Manitoba (2)

Ontario — SouthwestW.E. Baylis, University o f Windsor (1)M.M. Pintar, University o f Waterloo (2)

Ontario — Central and NorthR.G. Johnston, Trent University (1)M.H. Hawton, Lakehead University (2)

Ontario — EastM.J. Stott, Queen's University (1)E. W. Fenton. National Research Council of Canada (2)

Québec — Nord et OuestP.H. Depommier, Université de Montréal (I)M. Zuckermann, McGill University (2)

Québec — Sud et EstP.D. Marchand, Université Laval (1)L. G. Caron, Université de Sherbrooke (2)

New Brunswick & NewfoundlandM. D. Whitmore, Memorial University (1)F. Weil, Université de Moncton (2)

Nova Scotia and Prince Edward IslandA. Weingartshofer, St. Francis Xavier University (1)

( 2)

Editor — Canadian Journal of Physics:G. Rostoker, University o f Alberta

Editor — Physics in Canada/La Physique au Canada:J. Rolfe, Bank of Canada. Ottawa

Executive Secretary-Secrétaire Exécutif: M.L. Jento

MEMBRES CORPORATIFS 1983 CORPORATE MEMBERS

/ Allan Crawford Associates Ltd.V Anatek Electronics Limited

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Linear Technology Incorporated - </ Lumonics Research Limited i/ Mitel Semiconductor Limited ■" Moli Energy Limited v MPB Technologies Incorporated v Ontario Hydro r Optech Incorporated

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3

1983 Congress Congrès 1983General Information Renseignements généraux

The Physics Department of the University of Victoria is pleased to act as host for the thirty-eighth Annual Congress of the Canadian Association of Physicists, from Sunday evening, June 26 to Thurs­day, June 30, 1983. The Congress will be held jointly with the fourteenth meeting of the Canadian Astronomical Society.

Victoria has the most equable climate in Canada, and neither hot weather nor heavy rain is likely in late June. Either pleasantly warm, or rather cool, moist weather is normal for the season.

TRAVEL TO VICTORIAVictoria airport is located on the Saanich Peninsula about 25 km north-west of the University, which itself is 8 km north-east of the city centre. The airport is served by Air Canada, Canadian Pacific and Pacific Western Airlines, and Air B.C., the last of which operates from the South Terminal at Vancouver Airport (connec­tion via shuttle bus). Several transcontinental flights terminate in Victoria daily, usually with stops in Vancouver, Calgary or Edmonton. Charter flights are also available from the South Terminal at Vancouver Airport.

A limousine service links Victoria airport with the city, and stops on the way at the Mayfair Shopping Centre; the fare is $7. A taxi from the city to the campus is about $8, and from Mayfair, about $6. A taxi directly to the campus from the airport would cost over $20.

For those who obtain reduced fares (e.g. Skybus) terminating at Vancouver, and who wish to avoid the additional air fare to Victoria, a surface bus connection from Vancouver airport to downtown Victoria operates twice daily, at 1400 hrs and 2000 hrs. The trip takes about 3Vt hours including the ferry crossing, and the fare is $12.50 plus the ferry fare of $3.70. A bus from Van­couver Airport to the Airport Inn also connects with the intercity bus which boards every ferry.

For those travelling by car, the most convenient route is via B.C. Ferries, which can be boarded at Tsawwassen, south of Vancouver. The ferries normally depart every hour from 0700 hrs to 2100 hrs for Swartz Bay, about 30 km north of the University, but schedules are subject to change. The sailing time is about 1 Zi hours. The fare is currently $16.95 one way for car and driver, and $3.70 per passenger. Overheight (over 6 ft. 8 in.) and longer vehicles are charged higher fares.

REGISTRATIONCongress registration will be in the Student Union Building from 1400 to 2200 hrs on Sunday, June 26. Beginning at 0830 on Monday, registration will be in the foyer of the Elliott Building. Residence registration will be in the Craigdarroch Office Building, in the residence complex, indicated on the accompanying map.

Congress registration fees are:CAP Members and Invited Speakers $50Non members $65Teachers, graduate and undergraduate $12

studentsCompanions (per family) $ 5

Le Département de physique de l’Université de Victoria est heureux d ’être l’hôte du trente-huitième congrès annuel de l’Association canadienne des physiciens, du dimanche soir 26 juin au jeudi 30 juin 1983. Le congrès se tiendra conjointement avec la quatorzième réunion de la Société canadienne d’astronomie.

Victoria jouit du climat le plus uniforme du Canada, et on ne prévoit ni chaleur ni pluies abondantes à la fin juin. La tempéra­ture normale pour cette période de l’année est agréablement douce ou plutôt fraîche et humide.

TRANSPORT À VICTORIAL’aéroport de Victoria est situé dans le péninsule de Saanich, à environ 25 km au nord-ouest de l’Université qui. elle, se trouve à 8 km au nord-est du centre-ville. L’aéroport est desservi par Air Canada, CP Air, Pacific Western Airlines et Air B.C., cette dernière fonctionnant à partir du terminus sud de l'aéroport de Vancouver (navette d’autobus). Il existe plusieurs vols transcon­tinentaux quotidiens à destination de Victoria, habituellement avec escales à Vancouver, Calgary ou Edmonton. On peut égale­ment se prévaloir de vols nolisés à partir du terminus sud de l’aéroport de Vancouver.

Un service de limousine relie l’aéroport de Victoria à la ville, avec arrêt en cours de route au centre commercial Mayfair; le trajet coûte $7. Une course en taxi de la ville au campus coûte environ $8 et. du centre commercial Mayfair au campus, environ $6. Une course en taxi directement de l’aéroport au campus coûterait plus de $20.

Pour ceux et celles qui empruntent des vols à taux réduits (par ex., Skybus) à destination de Vancouver et qui désirent éviter le coût d’un vol supplémentaire jusqu'à Victoria, il existe deux fois par jour, soit à 14 h et à 20 h, un service de navette par autobus de l’aéroport de Vancouver au centre-ville de Victoria. Le trajet dure environ 3'/ι heures, y compris la traversée, et il coûte $12.50 plus $3,70 de traversier. Il y a enfin correspondance entre l’auto­bus qui relie l'aéroport de Vancouver au Airport Inn et l’autobus interurbain qui attend chaque traversée.

Dans le cas de ceux et celles qui voyagent par automobile, la méthode la plus pratique est d’emprunter les traversiez de laC.-B., à Tsawwassen. au sud de Vancouver. Les traversiers partent normalement à l’heure juste, de 7 à 21 h. à destination de Swartz Bay. environ 30 km au nord de l’Université, mais les horaires peuvent changer. La traversée dure environ I1/: heures. L’aller coûte actuellement S16.95 par automobile et conducteur, et $3,70 par passager. Il en coûte plus cher pour les véhicules hauts (plus de 6'8") et longs.

INSCRIPTIONL’inscription au congrès se fera de 14 h à 22 h. le dimanche 26 juin, au Student LInion Building. A partir de X h 30. le lundi matin, l’inscription se fera au foyer du pavillon Elliott. L’inscription à la résidence aura lieu au pavillon administratif Craigdarroch. dans le complexe résidentiel, selon les indicationsqui se trouvent sur la carte ci-jointe.

Les droits d ’inscription au congrès sont les suivants :

Membres de l’ACP et conférenciers invités $50Non-membres $65Enseignants, étudiants diplômés et sous-diplômés $12Compagnons (par famille) $ 5

4

PARKINGParking permits will be available free to those staying on campus and $1 per day for those staying off campus.

MEALSBreakfast is included in the price of residence accommodation. Lunch and dinner are available in the Cadboro Commons Dining Hall but tickets must be purchased in advance at prices of $4.75 and $5.75 respectively. Meals in the Dining Hall are served as follows:

Breakfast 0715 to 0830Lunch 1200 to 1300Dinner 1700 to 1800

REFRESHMENTSCoffee and juices will be available mid-morning and mid-afternoon in the Elliott Building adjacent to sessions and exhibits. Temporary memberships in the Faculty Club will be available to all registrants.

EQUIPMENT AND PUBLISHERS’ EXHIBITIONDisplays of scientific equipment and books will be located in the Elliott Building near the lecture theatres where the invited talks will occur, and in laboratories adjacent to those in which the poster sessions will be held.

TOURS AND SOCIAL EVENTS

Visits to local Scientific Institutions

1. Tuesday, June 28.Pacific Geoscience Centre and Institute of Ocean Sciences, at Patricia Bay, 25 km north of the University. Buses will leave the campus at 1330 hrs returning 1700 hrs. The cost will be $5 per person.

2. Wednesday, June 29.Dominion Astrophysical Observatory, 15 km northwest of the campus. Buses will leave the campus at 2030 hrs and return at about 2330 hrs. The cost will be $5 per person.

3. Thursday, June 30.TRIUMF accelerator, in Vancouver. Buses will leave the campus for the ferry terminal at 1100 hrs and return at 2000 hrs. The cost will be $15 per person, not including meals on board the ferries. Those who wish to do so may take their baggage with them and depart directly from Vancouver, instead of returning to Victoria.

For those who do not wish to visit TRIUMF a tour of UBC’s Anthropology Museum will be available that afternoon.

Social Tours and Companions' ProgramA reception will be held from 2030 to 2330 hours on Sunday, June 26 in the East-West Lounge of the Student Union Building, following the inaugural ceremony. Also a reception in the Faculty Club will follow the panel discussion on Wednesday, June 29.

Monday, June 27.Morning bus tour of Victoria cost $3 per person.

Visit to Butchart Gardens. Double-decker buses will leave the campus at 1930 hrs. returning at 2230 hrs to allow viewing the gardens and fountains by daylight and under illumination. The cost is $11 per person.

STATIONNEMENTDes permis de stationnement seront remis gratuitement à ceux et celles qui seront hébergés sur le campus et coûteront $1 par jour pour ceux et celles qui resterons hors campus.

REPASLe petit déjeuner est inclus dans le prix de l’hébergement. On pourra déjeuner et dîner à la salle à manger Cadboro Commons, mais il faudra acheter à l’avance des bons à cette fin, à raison de $4.75 et de $5.75, respectivement. La salle à manger est ouverte aux heures ci-après :

Petit déjeuner 07 h 15 à 08 h 30Déjeuner 12 h 00 à 13 h 00Dîner 17 h 00 à 18 h 00

RAFRAÎCHISSEMENTSOn pourra obtenir du café et des jus au milieu de la matinéeet de l’après-midi, au pavillon Elliott adjacent aux séances età l’exposition. Toutes les personnes inscrites pourront obtenir une carte de membre temporaire du Faculty Club.

EXPOSITION DE MATÉRIEL ET DE LIVRESUne exposition de matériel et de livres scientifiques sera installée au pavillon Elliott, à proximité des amphithéâtres où les conférences auront lieu, ainsi que dans des laboratoires adjacents à ceux où se dérouleront les séances de démonstration.

EXCURSIONS ET ACTIVITÉS SOCIALES

Visite d’établissements scientifiques locaux

1. Le mardi 28 juin.Le Pacific Geoscience Centre et l'Institute of Ocean Sciences, à Patricia Bay, 25 km au nord de l’Université. Des autobus quitteront le campus à 13 h 30, retour à 17 h. Il en coûtera $5 par personne.

2. Le mercredi 29 juin.Le Dominion Astrophysical Observatory, 15 km au nord-ouest du campus. Des autobus quitteront le c; mpus à 20 h 30, retour aux environs de 23 h 30. Il en coûtera $5 par personne.

3. Le jeudi 30 juin.L’accélérateur TRIUMF, à Vancouver. Des autobus quitteront le campus à 11 h pour se rendre au traversiez retour à 20 h. Il en coûtera $15 par personne, repas à bord des traversiers non compris. Ceux et celles qui le désirent peuvent emporter leurs effets et quitter directement de Vancouver, plutôt que de retourner à Victoria.

Pour ceux et celles qui ne voudront pas visiter le TRIUMF, une visite au Musée d’anthropologie de l'UCB a été organisée pour cet après-midi là.

Activités sociales et programmes des compagnonsUne réception aura lieu de 20 h 30 à 23 h 30, le dimanche 26 juin, au East-West Lounge du pavillon du Student Union Building, après la cérémonie d’inauguration. Une réception au Faculty Club suivra la discussion en panel le mercredi 29 juin.

Le lundi 27 juin.Excursion en autobus à Victoria, en matinée — coût: $3 par personne.

Visite des jardins Butchart. Trajet en impériale; départ du campus à 19 h 30 et retour à 22 h 30, de manière à pouvoir admirer les jardins et les fontaines à la lumière du jour et avec illumination. Il en coûtera $11 par personne.

5

A special recital presented by the music faculty at the University of Victoria School of Music at 2000 hrs. Admission $3 per person, proceedings going into a music scholarship fund.

Tuesday, June 28.Guided tours are arranged to visit Old Victoria, or the Provincial Museum, or Beacon Hill Park and the waterfront. The tours will last approximately two hours and buses will leave the University at 0930 hrs and 1630 hrs for downtown Victoria. The transporta­tion cost will be $2 one way. In the afternoon groups with guides will visit handicraft galleries, antique shops, etc.; approximate length of time is 2 hours commencing at 1400 hrs.

Wednesday, June 29.Nature walk. Bring walking shoes. Cost approximately $5 per person.

For spinners and weavers, a visit to the local Spinners and Weavers’ Guild will take place on June 29 in the afternoon.

Following a tour of Chinatown, a fixed menu dinner in a well- known Chinese restaurant in Victoria’s historic Chinatown at a cost of $14 per person. Transportation will be available to return participants to the University at a cost of $2.

ATHLETICS FACILITIESThe University’s Physical Education and Recreation Facilities are available to registrants presenting their conference badges at a charge of $1 per day. or $5 per week. The facilities include a swimming pool, exercise rooms, squash and tennis courts. Chip trails are available for jogging and walking (at no charge.)

ANNUAL BANQUETBy the kind invitation of the Commandant, this will now take place at Royal Roads Military College on the evening of Tuesday, June 28, hosted by the College’s Physics Department. The College is about 17 km west of the University, magnificently situated over­looking the Esquimalt Lagoon and the Strait of Juan de Fuca. The banquet will be a salmon barbecue, and weather permitting will take place out of doors. Since evenings are invariably cool in Victoria, delegates are advised to bring a sweater for this event. Parking is available on the College grounds, and car pooling for travel to the College is recommended, although buses will be available at 1700 hours and 1800 hours for those without cars. Aperitifs will be served from 1730, with the banquet commencing at 1930. For those arriving early, a walk in the College’s superb gardens is highly recommended.

Un récital spécial par la Faculté de musique de l’Université de Victoria aura lieu à 20 h. L’entrée est de $3 par personnes, les recettes en étant versées à un fonds de bourses d’études en musique.

Le mardi 28 juin.Excursions guidées aux fins de visiter les vieux quartiers de Victoria, ou le Musée provincial, ou le parc Beacon Hill et les quais. Les excursions dureront approximativement deux heures et les autobus quitteront l’Université à 9 h 30 et à 16 h 30 à destination du centre-ville de Victoria. L’aller coûtera $2 par personne. L’après-midi, des groupes avec guide visiteront des galeries d’artisanat, des boutiques d’antiquités, etc. ; les visites dureront environ deux heures, à partir de 14 h.

Le mercredi 29 juin.Marche dans la nature. Il faut se munir de chaussures pour la marche. Il en coûtera environ $5 par personne.

Pour les adeptes du filage et du tissage, une visite au Spinners and Weavers’ Guild aura lieu en après-midi.

Après une visite du Chinatown, un dîner à menu établi à l’avance est prévu dans un réputé restaurant chinois du Chinatown historique de Victoria, au coût de $14 par per­sonne. Pour revenir à l’Université, ceux et celles qui le désirent pourront se prévaloir du service offert moyennant $2.

INSTALLATIONS D’ATHLÉTISMELes personnes inscrites qui présenteront leurs macarons pourront, moyennant $1 par jour ou $5 par semaine, avoir accès aux installations d’éducation physique et récréatives de l’Université. Ces installations comprennent une piscine, des salles d’exercice et des courts de squash et de tennis. Il y a également des sentiers pour le jogging et la marche (sans frais).

BANQUET ANNUELA la suite de l’aimable invitation du Commandant, le banquet annuel aura lieu au Collège militaire Royal Roads, le mardi 28 juin en soirée, sous les auspices du Département de physique du Collège. Le Collège est situé à environ 17 km à l’ouest de l’Université, sur un magnifique site surplombant le Lagon d ’Esquimalt et le détroit Juan de Fuca. Le banquet se com­posera d’un barbecue de saumon et, si la température est clémente, se déroulera au grand air. Etant donné que les soirées sont toujours fraîches à Victoria, on conseille aux délégués d ’emporter un chandail pour l’occasion. Il existe du stationnement sur les lieux; on recommande toutefois de se grouper pour s’y rendre par automobile, ou de prendre les autobus qui partiront à 17 h et à 18 h. Des apéritifs seront servis à 17 h 30 et le banquet débutera à 19 h 30. Nous recommandons fortement à ceux et celles qui arriveront tôt de prendre une marche dans les superbes jardins du Collège.

LOCAL COMMITTEE/COMITÉ LOCAL

Chairman C.D. Scarfe Président Employment Centre H.S. Sandhu Centre d'emploiVice Chairman J.T. Weaver Vice président Exhibits G.A. Beer Exposition

Treasurer J. Goudy Trésorier Meeting Rooms G.R. Friedmann Salles de conférencesSecretary Rita Brown Secrétaire Publicity R.E. Horita Publicité

Accommodation G.R. Mason Hébergement Regional Labs Visits H.W. Dosso Visites de laboratoiresBanquet & Reception C.E. Picciotto Banquet & réception Registration J.B. Tatum Inscription

Companions’ Program Pat Pearce Programme récréatif Tours Coordinator D.E. Lobb Coordonnateur des visites

6

7

8

Lecture Wing Main Floor Laboratory WingEliott Building

Lower Floor Plan

9

Canadian Association of Physicists Medallists 1983 Lauréats de l’association canadienne des physiciens 1983

CAP Medal for Achievement in PhysicsP.A. Egelstaff

University of Guelph

Herzberg MedalW.G. Unruh

University of British Columbia

Canadian Association of Physicists Prize Exam 1983 Résultats de l’examen de l’association canadienne des physiciens 1983

One hundred and thirty-four students from twenty-one universities competed this year. The exam was administered by a Committee from the University of B.C. The names of the first, second and third prize-winner are shown followed by the next seven in alphabetical order.

F. Lamarche FIRST PRIZE Université d’OttawaJ. Thornburg SECOND PRIZE Simon Fraser UniversityD. Carrier THIRD PRIZE Université LavalP. Geiger University of TorontoT. Hsu Queen’s UniversityH. Martel Université de MontréalG.D. Quinlan McGill UniversityA. Reich University of TorontoM. Reynolds Simon Fraser UniversityT. Stevenson University of British Columbia

LIST OF EXH1B1TORS/L1STE DES EXPOSANTS Congrès A C P/SC A 1983 CA P/C A S Congress

Manufacturers and Suppliers/ Manufacturiers et Représentants(as of May 3, 1983)

AANDERAA INSTRUMENTS LTD. W.G. ALEXANDER LIMITED ALLAN CRAWFORD ASSOCIATES ANALYTECH COMPONENTS INC. CTF SYSTEMS INC.EG & G ORTEC

INTERFAX SYSTEMS INC.LeC'ROY RESEARCH SYSTEMS CORPORATION METEOR COMMUNICATIONS (CANADA) CORP. MITEL CORPORATION RADIONICS SCIENTIFIC’ INC.RAE DATA SYSTEMS TASMAN SCIENTIFIC INC.TECHNICAL MARKETING ASSOCIATES LIMITED VARIAN CANADA INC.

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Invited Speakers/Conférenciers invités

ADELBERGER, E.G., University o f Washington; AG2: The Parity Non-Conserving Nuclear ForceASTBURY, A., CERN and TRIUMF; CB4: The Discovery of the W IntermediateBERLINSKY, A.J., University o f British Columbia; AE1: Recent Work on Spin-Polarised HydrogenBLACKMORE, E.W., TRIUMF; FG4: TRIUMF Kaon Factory PlansBOAL, D.H., Simon Fraser University; AB3: Nuclear Science in the Early UniverseBRYMAN, D.A., TRIUMF— University of Victoria; FC2: A New Measurement of the π — ev Branching RatioBUCHINGER, F., McGill University; AF2: Probing the Nucleus by Laser SpectroscopyBURBANK, M.B., CTF Systems Inc.; AH1: Industrial Physics at CTF Systems Inc.CAMERON, J.A., McMaster University; CD1: Nuclear Spin Determination Without TearsCAMPBELL, E.M., Lawrence Livermore National Laboratory; AD2: The Role of Wavelength in Laser-Driven Inertial FusionCANNON, W., York University; FF2: The CLBA and A National Research Program in Geodesy and GeophysicsCARNEGIE, R.K., Carleton University; FG1: OPAL and LEP: A New High Energy Physics ExperimentCARSWELL, A.I., York University and Optech Incorporated; FH 1CHAPMAN, D., Royal Frie Hospital School of Medicine; FAI: Biomembranes, Basic Science and Future Technology DAHN, J.R., National Research Council; AA3: Lithium Intercala­tion in Layered CompoundsDALGARNO, A., Harvard-Smithsonian Centre for Astrophysics; CCI: Atomic and Molecular Physics in Astrophysical Sources DAUTOVICH, D.P., Ontario Hydro; CF2: Tritium Aspects of FusionDAVIS, J.H., University o f Guelph; FA3: A Physicist’s Model MembraneDIXIT, M., National Research Council o f Canada; CB2: Search for Massive NeutrinosDRAKE, T.E., University o f Toronto; CEI: What do Scattering Experiments Reveal about the Proton-Nucleus Interaction?EGELSTAFF, P.A., University o f Guelph; EA2: Neutron Scattering Studies of Liquids and Dense GasesELLIS, S., University o f Washington; CB3: In Search of Jets EVANS, E.A., University of British Columbia; FA2; Mechanical Calorimetry of Synthetic and Natural MembranesFLEMING, D.G., University of British Columbia; CD2: pSR and Positive Muon Spectroscopy (at TRIUMF)FRINDT, R.F., Simon Fraser University; AA1: Intercalation of Transition Metal DichalcogenidesGEORGALLAS, A., McGill University; FA4: Theory of Phos­pholipid Monolayers and BilayersGOWER, A., University o f Victoria: CH3: Women in Physics: Why Not?GREYTAK, T.J., Massachusetts Institute o f Technology; AE2: Experiments on Spin-Polarised Atomic HydrogenHARDY, J.C., AECL, Chalk River Nuclear Laboratories; AGI: Superallowed /8-decay: Weak Interaction Studies at High Precision

HESSER, J.E., Dominion Astrophysical Observatory; AC2: Star- lab: An International Observatory in Earth OrbitHUTCHEON, D.A., TRIUMF — University o f British Columbia; FC1: Radioactive Capture at Intermediate EnergiesJOHNSTON, THE HONORABLE DONALD J„ Minister of State, Economic Development and Science & Technology; Opening AddressKIRCZENOW, G., Boston University; AA2: Models of the Struc­ture of Graphite Intercalation Compounds KIVELSON, S.A., State University of New York; CA3: Solitons of Fractional ChargeLEE, D.M., Cornell University; AE3: NMR Induced Recombina­tion and Free Induction Decay Studies of Spin Polarised HydrogenLEIBBRANDT, G., University o f Guelph; CA1 : Aspects of Soliton BehaviourLEVINE, S., Manche··' «^'niversity; FEE The Electrical Double Layer and ColloicCa^articlesLLEWELLYN, E.J., University o f Saskatchewan; AC4: Spectro­scopy without a SpectrometerMacLEOD, J.M., Herzberg Institute of Astrophysics — NRC: CC3: Long Chain Carbon Molecules in Interstellar SpaceMacNABB, G.M., Natural Sciences and Engineering Research Council; FH4MARTIN, J., IPP Scientist, University o f Toronto; FG2: Canadian Participation in HERAMcCONNELL, J .C, York University; CC4: Atomic and Molecular Processes in Planetary AtmospheresMcGEER, Patrick DM1McKEE, J.S.C., University o f Manitoba; CE2: The Case for P.A.U.L.I.McKEON, D.G.C., University of Western Ontario; AB2: Some Applications of the Renormalization Group in Particle PhysicsNAGLER, S.E., I.B.M. — T.J. Watson Research Center; CA2: Solitons, Propagating Walls, and Neutron Scattering in One Dimensional Magnetic SystemsO’BRIEN, R.N., University of Victoria; FE2: Membrane Processes and Permeable SurfacesOVENDEN, M.W., University of British Columbia; CH2: Social Issues in Canadian Physics ClassroomsPATE, B.D., TRIUMF — University of British Columbia; AH2: PET: Applied Nuclear Physics and Chemistry at TRIUMF/UBCPEPIN, H„ INRS — Énergie, Université du Québec; ADI: Supra- thermal Electron Transport in Laser Produced PlasmasPINTAR, M.M., University o f Waterloo; FB3: Rotational Tunnel­ing of Atomic Groups in Solids: A Review of Experimental Techniques in the Energy Range 10 10 to 10 !eVPLAVEC, M.J., University o f California: EA3: Strongly Inter­acting Binary Stars: Freaks or Rosetta Stones?PORKOLÁB, M., MIT. and Plasma Fusion Center: CF1: Lower Hybrid Current Drive on TokamaksPRENTICE, J.D., University of Toronto; FG3: New Results on b quarks from the ARGUS CollaborationREDHEAD, P.A., National Research Council Canada; FH2REEVES, E.M., Spacelab Flight Division — NASA; AC1: Space Optical Systems of the Coming Decade

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RICHARDSON, H., Dominion Aslrophysical Observatory — NRC; AC3. Design of Earth Viewing Space Optics: Auroral Imager; Chlorophyl and Airglow SpectrographROBERTSON, B., University o f Regina; CHI: The Science Council Study on Science Education and Its RecommendationsROBERTSON, L.P. and STENTON, D.E., University of Victoria; DBI: Workshop on Use of Microcomputers as Data Acquisition Systems in the Physics ClassroomsROSTOKER, G„ University o f Alberta: CH4: More Canadian Technological Applications in High School Physics?RUDAZ, S., University o f Minnesota: CBI: Grand Unification and SupersymmetrySANTHANAM, K.S.V., Tala Institute o f Fundamental Research: FE3: Electrochemistry at Polymer Covered ElectrodesSEAQUIST, E.R., University o f Toronto; FFI: The Impact of a Continental Array on Current Problems in Radioastrophysics

SMITH, Stuart L., Science Council o f Canada; EH3STROM-OLSEN, J.O., McGill University; FB2: Metallic Glasses: The Simplest Type of Metal?SZÖGHY, I.M., Université Laval; AFI: Prompt and Radiogenic X-rays from Heavy Ion ReactionsTIMUSK, T. and NG, H.K., McMaster University; FBI: Far Infra­Red Properties of the (TMTSF);X Compounds at Low Tempera­tureTURNER, B., National Radio Astronomy Observatory; CC2: Mole­cules and Probes of the Physics of Star-Forming RegionsUNRUH, W.G., University of British Columbia: AB4: Black Holes, Archimedes and the Second Law of Thermodynamics; EAI: Quantum Noise and Gravity Wave DetectionWORTIS, M., University o f Illinois; ABI: Introduction to the Renormalization Group Method

Listeners, Speakers, and Session Chairmen Special Instructions for Timed Papers

The papers will be timed in order to make it possible for listeners to transfer from one session to another.

LISTENERS1) Please arrive at a lecture room promptly before the next paper is to begin.2) Leave a session unobtrusively, preferably either during or at the end of the question and answer period.

SPEAKERS1) Make your slide projection arrangements before the start of your session.2) Be ready to start your talk on time.3) Pace your talk to end well before the next talk begins: about 3 minutes for a contributed paper and about 10 minutes for

an invited paper.4) Answer questions and perhaps comments as completely and briefly as made necessary by the response of the audience.5) Obey your chairman’s instructions.6) Most important, practice giving your talk before the meeting. Remember, you are the ambassador of your depart­

ment and institution, and you will be judged by your audience.

CHAIRMEN1) Ciet to the session room about ha lfan hour before your session begins. Check that all needed projection and auxiliary

equipment are present and operational. Check that your speakers are present.2) Start each paper right on time.3) Make sure each speaker stops talking well before the next paper begins.4) Keep the question periods interesting, lively and productive. Read over the papers in your session beforehand. II

necessary, prepare comments and questions.5) Do not let any discussion period get out of hand, either on the speaker's or the questioners' side.6) If no one appears to give a paper, then either close the session until the time of the next scheduled speaker or else use the

time imaginatively, perhaps begin a discussion of earlier papers.7) Linder no eireumstanees may the order of giving the papers differ from that given in the program, even though you

may, in your wisdom, see a better arrangement than that determined by the Program Committee.

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PROGRAM SUMMARY/RÉSUMÉ DU PROGRAMME

The letter code of the session, the starting time, the location and the topics of each session are given in order. Sessions will be held in the Eliott Building unless otherwise indicated. (The personal names are those of invited speakers).

SUNDAY, JUNE 26

9:00 Gold Room CAS CouncilCadboro

15:00 Green Room CAP CouncilCadboro

19:30 Theatre Opening Ceremony: The Honorable Donald J. JohnstonSUB

MONDAY, JUNE 27

AA 9:00 168 Intercalation Compounds: FRINDT, KIRCZENOW, DAHNAB 9:00 060 Theoretical Physics Symposium: WORTIS, McKEON, BOAL, UNRUHAC 9:00 062 Optics in Space: REEVES, HESSER, RICHARDSON, LLEWELLYNAD 9:00 162 Laser Plasmas I: PEPIN, CAMPBELLAE 9:00 167 Spin-Polarised Atomic Hydrogen: BERLINSKY, GREYTAK, LEEAF 9:00 061 Nuclear Physics I: SZÖGHY, BUCHINGERAG 10:35 061 Nuclear Physics II: HARDY, ADELBERGERAH 9:00 160 Industrial and Applied Physics in British Columbia: BURBANK, PATE

13:30-16:30 POSTER FESTIVAL — PART 1

BA 136 Surfaces and Layered MaterialsBB 136 Biophysics/LiquidsBC 136 μ$Κ, Positron AnnihilationBD 144 Atomic and Molecular PhysicsBE 129 Surface ScienceBF 129 Optics and LasersBG 129 Aeronomy and Space PhysicsBH 139 Physics and SocietyBJ 128 Industrial and Applied PhysicsBK 128 Instrumentation and Experimental Techniques

16:30 ANNUAL MEETINGS OF CAP DIVISIONS

061 Division of Aeronomy and Space Physics060 Division of Optical Physics062 Division of Theoretical Physics160 Division of Industrial and Applied Physics162 Division of Surface Science

19:30 062 Open Discussion — Formation of a Canadian Institute for Theoretical Astrophysics

21:00 144 Overview of VLSI for the 80’sMacLaurin

21:00 166 Meeting of the Advisory Board, CAP Theory Institute (Board Members only)

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TUESDAY, JUNE 28

CA 9:00 168 Solitons: FEIBBRANDT, NAGFER, KIVEFSONCB 9:00 162 Particle Physics I: RUDAZ, DIXIT, EFFIS, ASTBURYCC 9:00 167 Atomic and Molecular Processes in Astrophysical Sources: DAFGARNO, TURNER, MacLEOD,

McCONNEFFCD 9:00 060 Nuclear Physics III — Spectroscopy and Applications: CAMERON, FFEMINGCE 10:35 060 Nuclear Physics IV — Scattering and Accelerators: DRAKE, McKEECF 9:00 061 Fusion Physics I: PORKOFAB, DAUTOVICHCG 10:45 061 Fusion Physics IICH 9:00 062 Physics Education: ROBERTSON, OVENDEN, GOWER, ROSTOKER

11:00 062 Annual Business Meeting of the CAP Division of Physics Education

DA 13:30 167 Astronomy and AstrophysicsDB 13:30 128a Physics Education Workshop (Moved lo Wednesday 13:30, Room 139)

13:30- 16:30 POSTER FESTIVAL — PART II

DC 136 Magnetic Properties of SolidsDD 136 Phase Transitions, Lattice Dynamics, Low Temperature PhysicsDE 139 Optical and Electrical Properties of SolidsDF 139 Medical and Biological PhysicsDG 139 Education and TrainingDH 128 Plasma PhysicsDJ 129 Particle PhysicsDK 129 Nuclear Structure, Reactions and ScatteringDF 144 Intermediate Energies

16:30 ANNUAL MEETINGS OF CAP DIVISIONS

167 Division of Atomic and Molecular Physics168 Division of Condensed Matter Physics060 Division of Nuclear Physics162 Division of Particle Physics061 Division of Plasma Physics

WEDNESDAY, JUNE 29

EA 8:30 MacFaurin CAP/CAS Plenary Session: UNRUH. EGELSTAFF, PLAVEC144

FA 13:00 168 Biophysical Membranes: CHAPMAN, EVANS, DAVIS, GEORGALLASFB 13:00 060 Organic Superconductors, Metallic Glasses and Rotational Tunneling: TIMUSK, STROM-OLSEN.

PINTARFC 13:00 062 Nuclear Physics V — Intermediate Energies: HUTCHEON, BRYMANFD 13:00 061 Laser Plasmas IIFE 13:00 162 Surface Science: O’BRIEN. SANTHANAMFF 13:30 167 Canadian Long-Baseline Array: SEAQUIST, CANNONFG 13:00 160 Particle Physics II: CARNEGIE, MARTIN, PRENTICE, BLACKMOREFH 16:00 MacFaurin Manpower for R & D in the 80’s: CARSWELL, REDHEAD, SMITH, MacNABB

144

19:00 167 Open discussion on STARLAB21:00 060 CAP Council

THURSDAY, JUNE 30

9:00- 160 Associate Committee on Astronomy17:009:00- 166 CLBA Planning Committee17:00

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CAP-GAS Congress Program 1 9 8 2 ^

Programme du Congrès ACP

SUNDAY, JUNE 26,1983GOLD ROOM, CADBORO COMMONS BLOCK

9:00-17:00 Meeting of CAS Council / Réunion du Conseil de la SCAChairman/President : V, Gaizauskas

SUNDAY, JUNE 26, 1983GREEN ROOM, CADBORO COMMONS BLOCK

15:00-17:00 Meeting of CAP Council / Réunion du Conseil de l'ACPChairman/President: A.R. Crawford

SUNDAY, JUNE 26,1983THEATRE, STUDENT UNION BUILDINGChairman: B.P. StoicheFf

19:30 Opening Ceremony-

Welcoming Remarks:

H.E. Petch, President University of Victoria

V, Gaizauskas, President Canadian Astronomical Society

A.R. Crawford, President Canadian Association of Physicists

Address :

The Honorable Donald J. Johnston, Minister of State Economic Development and Science & Technology

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MONDAY, JUNE 27,1983 INTERCALA TION COMPOUNDSROOM 168Chairman: J.C. Irwin

9:00AA1 Intercalation of Transition Metal Dichalcogenides

R.F. Frindt, Szánon ïKUbQA U niveAbitlJ

A brief overview of intercalation of the transition metal dichalcogenide layered compounds will be presented, along with some recent work on staging, island formation and island motion for Ag inter­calated T1S9.

9 : AO AA2 Models of the Structure of Graphite Intercalation Compounds

G. Kirczenow, B oston UnlvQAAlly

10:20AA3 Lithium Intercalation in Layered Compounds

J.R. Dahn and W.R. McKinnon, V lv iA iO n 0 i C h w l i lA y , HatlOYiaZ RoMKUick C o u n c il

We will describe experimental techniques for investigating the intercalation of lithium in layered compounds. We will show how simple electrochemical measurements (using intercalation batteries) yield information about lithium order-disorder transitions, the formation of staged structures and even the number of stacking faults present in layered compounds. The results of recent experiments on LixTaS2 will be used to illustrate the techniques.

MONDAY, JUNE 27,1983 THEORETICAL P H YSIC S SYM PO SIU MROOM 060Chairman: W.J.I.. Buyers

9:00AB1 Introduction to the Renormalization Group Method

M. Wort is, U n lv & u lty o& J l t l n o l6

9:40AB2 Some Applications of the Renormalization Group in Particle Physics

D.G.C. McKeon, UyU,\)OJOxL ty o& OJeAtoAn OntaAlo

10:20 Break

10:40AB3 Nuclear Science in the Early Universe

d .h . Boái, Sünön FxjZ6eA UniveA6-Lty

It has been more than a decade since the Big Bang model of the early universe was used to predict the abundance of 4He produced in the first few minutes after the singularity* Times even earlier that this epoch take one to, and beyond, temperatures and densities which are currently under investigation in the collision of relativistic particles. This lecture will review some of the phase transitions which may have occured at these very high densities and temperatures. Included will be descriptions of the effects of symmetry breaking in gauge theories, the quark to hadron transition, and possible liquid to gas transitions of nuclear matter.

11:20AB4 Black Holes, Archimedes and the Second Law of Thermodynamics

w.G. Unruh, UnlvoAAÂXy o& B>Utc6k Columbia

16

MONDAY, JUNE 27,1983 OPTICS IN SPACEROOM 062Chairman: R.W. Nicholls

9:00AC1 Space Optical Systems of the Coming Decade

E.M. Reeves, Spacelab F t i g h t Vtvtáton-NAS A HejxdquaAteM

9:45 AC 2 Starlab: An International Observatory in Earth Orbit

J.E. Hesser, Vom inton A ó tio p h y ó tc a t Ob^oAvatony

Starlab is a tripartite proposal from NASA, Canada, and Australia to put a lm Ritchey Chretien telescope in Shuttle orbit for direct photography and long-slit spectroscopy. The telescope, to be built by Canada, would give diffraction limited images over a 0.5 field for wavelengths > 250 nm. Photon-counting, signal-generating, detectors would be used over the wavelength range 115 nm to 1.2 μ. Canada would integrate the telescope and scientific instrument package (an Australian responsibility), for delivery to NASA which has promised two six-month platform missions and one or two Shuttle-attached shake-down missions starting in 1991. In 1982 August, Australia committed AS3.337M for Phase B studies of the instrument package and Canada currently contributes some $200k + 1.5 man years/year. The direct imaging field proposed for Starlab is at least 1 0 0 x larger than that of Space Telescope (ST) and would provide an important wide-field survey complement. Starlab will also be able to undertake several programs of fundamental importance in astrophysics and cosmology which would be impossible with ST.

10:30 Break

10:45 AC 3 Design of Earth Viewing Space Optics: Auroral Imager; Chlorophyl and Airglow Spectrograph

H. Richardson, Dominion K&txophyiiaxl Ob&vwatotiy - NRC

11:30AC4 Spectroscopy without a Spectrometer

E.J. Llewellyn & I.C. McDade, U niveAiity of, Saikutchm in

The absorption of radiation has been used for many years to measure the concentration of absorbers in the path. In the atmosphere a similar technique has been used with the solar disk as the radiation source. However, the measurements in this case are long path observations and must be differentiated to obtain local concentrations. Recently in the Canadian Space Research program a number of experiments have been proposed to measure in-situ minor constituent concentrations using resonant scattering and absorption. The use of resonance lamps in the atmosphere is much more complicated than in the laboratory and in the case of oxygen is further complicated by the differing absorption in each component of the triplet. However, an additional major difficulty in the space application is presented by the relative velocity of the lamp to the medium. For typical rocket velocities the line center can be shifted by almost the Doppler width but this fact can be used to derive additional information about the atmosphere. In this paper the use of resonance lamps is discussed in detail and their application to a Doppler spectrometer outlined.

MONDAY, JUNE 27,1983 LASER PLASM AS /ROOM 162Chairman: A. Offenberger

9:00ADI Suprathermal Electron Transport in Laser Produced Plasmas

H. Pepin, INRS-EneAgie., U n iv z u i t í du. Quebec

9:45 AD 2 The Role of Wavelength in Laser-Driven Inertial Fusion

E.M. Campbell, Lauüíncí LiveAmom National Laboha.toh.y

Laser wavelength plays an important role in the physics of laser-driven inertial confinement fusion. Laser-plasma coupling, energy transport, radiation physics, and hydrodynamics are all strongly influenced by the wavelength of the laser. In this presentation, we will summarize our experimental and theoretical understanding of the effects of wavelength in laser-plasmas. In addition, recent experiments which used the 10 kJ, 0.525 pm Novette laser to test the physics of submicron light interaction in large plasmas will also be discussed.

17

9:00AE1 Recent Work on Spin-Polarised Hydrogen

A.J. Berlinsky, U n iv e A il ty of, B tU tl ih Columbia

9:45AE2 Experiments on Spin-Polarised Atomic Hydrogen

T.J. Greytak, H a a a c h a ie t t s T n & ttfu te o f T echnology

MONDAY, JUNE 27,1983 SPIN-POLARISED A TOMIC HYDROGENROOM 167Chairman: J.W. McConkey

10:30 Break

10:45AE3 NMR Induced Recombination and Free Induction Decay Studies of Spin Polarised Hydrogen

D.M. Lee, Cornell U vU veU ltlJ

Studies of spin polarised hydrogen gas in a magnetic field of about 8 tesla have been performed with nuclear magnetic resonance and sensitive pressure gauge techniques at temperatures below 0.5 K. Atomic hydrogen densities as large as 10*' atoms per cm3 have been detected. Free induction decay signals have been directly observed, with sample densities as small as 10ll* atoms per cm3 giving substantial signals. Wall recombination into molecular hydrogen is inhibited by coating the sample chamber walls with a superfluid ‘‘He film. With these techniques, measurements of recombination rate constants and nuclear spin relaxation rates have been carried out.

♦Support provided by joint Army Research Office - National Science Foundation Grant DMR-7822204 and DMR-8211508.

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9:00Prompt and Radiogenic X-rays from Heavy Ion ReactionsI.M. Szöghy, UniveM<ct£ Laval

The identification of reaction products from the fusion-evaporation process in particularly difficult due tg the onset of fast beta decay. Even the direct observation of the residues - emerging near 0 from the target and detected after a long flight time - offers no information on the first nanoseconds. Prompt γ -rays from highly excited residues are mainly statistical and structureless, thus providing information only on their multiplicity. As a result, the prompt X-rays - partly from vacancy production during the reaction but mostly from internal conversion of prompt γ-rays - represent a valuable information: the production yield of residual elements. The observation of these X-rays and their distinction from radiogenic ones is discussed in detail. To be useful, their yield has to vary smoothly with excitation energy and mass of the reaction product. In this respect, the trend of KX-ray yields from primary fission products is most supportive.

9:40AF2 Probing the Nucleus by Laser Spectroscopy

F. Buchinger, HcGiLl U n iv e /U ity

Nuclear ground state properties such as spin, moments and the change of the charge distribution with neutron^number are obtained from measurements of the hyperfine structure and the isotope shift of optical spectra. The introduction of laser techniques to optical spectroscopy and the development of on-line isotope separators which are able to produce high intensity beams of unstable nuclei, now allow more systematic studies of an element over an extended series of isotopes. We present here, as an example of recent progress in the field, the work of the laser spectroscopy groups of the ISOLDE mass separator of CERN where over two hundred different isotopes of 13 elements have so far been studied.

MONDAY, JUNE 27, 1983ROOM 061Chairman: B. Cujec

10:25 Break

NUCLEAR PH YSIC S I: HE A VY IONS ORDINAR Y AND EXO TIC

MONDAY, JUNE 27, 1983 ROOM 061Chairman: W. McLatchie

10:35AGI Superallowed β-decay: Weak Interaction Studies at High Precision

J.C. Hardy, AECL, Chalk HiveA Nucleon. LabonotoAi&r

Under selected circumstances the nucleus can act as a versatile laboratory for testing the properties of fundamental forces. In particular, the weak force is responsible not only for nuclear beta decay but also for the decay of the muon and certain modes of hyperon decay; consequently, precision measurements of the decay between 0+ nuclear states can be used to test the conservation of vector current (CVC) and the universality of weak interactions. Recent experimental advances have led to a considerable improvement in the precision of these nuclear measurements. Experiments will be described in which relative Q-values are determined to ±150 eV, and lifetimes measured with isotope-separated sources to about ±0.03%. The resultant ft values will be used to establish the validity of charge-dependent-mixing calculations and ultimately to extract the vector coupling constant. Implications will be drawn for CVC, universality and the Vu(j quark mixing element.

11:20AG2 The Parity Non-Conserving Nuclear Force

E.G. Adelberger, U n iv e M ity W orkington·

NUCLEAR PH YSIC S II: WEAK INTERACTIONS

The weak interaction between nucleons induces a very small parity non-conserving (PMC) component in the short-range nuclear force. Since the weak force does not respect the isospin symmetry there is no simple connection between the FNC interaction in the n-n, n-p and p-p systems. The development of high-precision accelerator-based techniques for experiments in the MM system and in light nuclei has made it possible to place experimental constraints upon the relative strength of the PNC force in the n-n, n-p and p-p systems. The results are in accord with predictions based on the quark model of hadrons and the standard model of the weak interaction. My talk vili emphasize the reasons for choosing particular nuclear transitions, the experimental techniques employed, and the '‘tricks'1 used to reduce nuclear structure uncertainties in the extraction of the parameters of the PMC MU force.

19

9:00AH1 Industrial Physics at CTF Systems Inc.

M.B. Burbank, CTF Slj&toxMi JnC.

The environment of the industrial laboratory can offer a number of interesting opportunities for research and development within physics related disciplines. The paper will discuss various projects in which CTF Systems Inc. has been involved over the past 10 years. The projects may be roughly grouped into four major areas: ultrasonics, SQUID magnetometry, superconducting magnets, and computer automation. Various developments within these ultrasonic areas have been: transducer developments for measurement of wall thickness of small diameter tubes, sensitive transducers for head-on detection of small cracks in steel, and piezoacoustoelectric phase insensitive ultrasonic detectors. SQUID instrumentation for the high resolution detection of magnetic field changes has been CTF's major area of interest. Work in this area has involved a vertically integrated capability in SQUID sensors, composite liquid helium dewars, high speed/ wide dynamic range SQUID electronics and various data acquisition and signal analysis software developments. This capability has been applied to the development of various biogradiometer, rock magnetometer and geomagnetometer commercial systems. Still within the field of cryogenic engineering, but within the domain of high field applications, CTF Systems Inc. is involved in the development of superconducting magnets and dewars for the Canadian Maglev Program. Many systems developed by CTF are computer automated. Some examples are: systems for measurement of corrosion in naval boiler tubes, automated rock magnetometers, and an automated gantryfor biomagnetometer systems. In all cases development projects are oriented towards practical applications with a view to commercial exploitation wherever possible.

MONDAY, JUNE 27,1983ROOM 160Chairman: R. Hoff

9:45AH2 PET: Applied Nuclear Physics and Chemistry at TRIUHF/UBC

B.D. Pate, TRIUMF - UniveM'itij 0& BSbCtibh Columbia

Positron Emission Tomography (PET) is a modern imaging technique which allows the measurement of organ physiology in an alert and comfortable human subject. A tomograph to the PETT VI design has been constructed at UBC/TRIUMF for brain research. The performance of the tomograph is discussed, as is the production of positron-emitting radionuclides at the TRIUMF CP-^2 cyclotron, and their synthesis as PET scanning agents. The first applications of the UBC PET scanner have been in the study of movement disorders (and particularly Parkinson's disease), dystonia, cerebral hemodynamics, and Alzheimer's disease.

INDUSTRIAL AND APPLIED P H YSIC S IN BRITISH COLUMBIA

10:30 Break

TECHNOLOGICAL INNOVA TION B Y YO UN G PHYSIC IS TS

Results of the Division of Industrial and Applied Physics Competition for the Selection of Innovative Young Physicists will be announced and the individuals selected will have the opportunity to present a short description of their work.

20

MONDAY, JUNE 27, 1983

13:30-16:30 Poster Festival-Part I Festival de séances de démonstration-Première partie

ROOM 136

SURFACES AND LAYERED M ATERIALS

BAI Reactive Sputtering of A]L in Ar/N0 and Ar/0o Atmospheres.* J. AFFINITO, R. McMAHON, M.J. BRETT and R.R. PARSONS, University of B.C. - In reactive sputter­ing the glow discharge is found to be unstable in the regime of partial target coverage because the chemical reactions between the reactive gas and the target surface are coupled to the gettering action of the sputtered metal film via the reactive gas partial pressure. This coupling leads to positive feedback cycles which results in either a completely covered target and high reactive gas partial pressure or a bare target surface with low reactive gas partial pressure. We have found that control of the target voltage allows control of the discharge in the region of partial target coverage for target-reactive gas systems in which target coverage is dominated by ion plating from the sputtering current as opposed to chemisorption from the reactive gas. A model is developed which allows for these two mechanisms and is in good agreement with experiments performed with an A1 target in Ar/(>2 (chemisorption dominant) and Ar/N2 (ion plating dominant) atmospheres. The model allows calculation of film composition from the discharge characteristics.

*Supported by NSERC Grant No. 67-0132

BA2 Some Properties of Vacuum Deposited Zn„P~ Films.* U. VON SACKEN and D.E. BRODIE, (GW P ) ^ f - Waterloo Campus - Zinc phosphide is a promising semi­conductor for use as the absorber in thin film solar cells. Polycrystalline films have been preparedin an oil-free high vacuum system by vapor deposition. The conductivity, optical absorption, and morphology of Ζη-,Ρο films prepared under various deposition conditions has been studied in an attempt to optimize their properties.

*Supported by NSERC.

tGuelph-Waterloo Program for Graduate Work in Physics.

BA3 E f f e c t s o f S u r f a c e R o u g h n e s s o n A t t e n u a t e d T o t a l R e f l e c t i o n S p e c t r a o f A g Films.A. P i n a r d , F . E . G i r o u a r d a n d V . V . T r u o n g , D e p t , o f P h y s i c s - M a t h . r U n i v . d e M o n c t o n — T h e K r e t s c h m a n n ^ 1) c o n f i g u r a t i o n , c o n s i s t i n g o f a p r i s m - m e t a l - a i r a r r a n g e m e n t , w a s e m p l o y e d . M e a s u r e m e n t s w e r e p e r f o r m e d f o r f i l m s o f 5 2 . 5 n m m a s s t h i c k n e s s w i t h i n c r e a s i n g s u r ­f a c e r o u g h n e s s . The. a n g u l a r s p e c t r a , o b t a i n e d f o r p - p o l a r i z e d l i g h t o f w a v e l e n g t h o f 6 3 2 . 8 nnv h a v e s h o w n a m a r k e d d i s p l a c e m e n t o f t h e r e f l e c ­t i o n m i n i m u m to l a r g e r a n g l e s a n d a b r o a d e n i n g o f t h i s s t r u c t u r e w i t h i n c r e a s i n g s u r f a c e r u g o ­s i t y . T h e s e f a c t s c o m p a r e w e l l w i t h c a l c u l a ­t i o n s f r o m m u l t i l a y e r e d t h i n f i l m s y s t e m . In s u c h s y s t e m , w e i n t r o d u c e d a c e r m e t l a y e r to r e p r e s e n t t h e r o u g h n e s s at t h e m e t a l / d i e l e c t r i c i n t e r f a c e . T h e e f f e c t i v e d i e l e c t r i c c o n s t a n t o f t h i s l a y e r w a s c a l c u l a t e d f r o m a n e f f e c t i v e m e d i u m t h e o r y .

. K r e t s c h m a n n , . F h y s . , 2 4 1 , 313 (1971) .

BA4 Electrical^and Optical Properties of a-Si:C.* C.J. MOORE and D.E. BRODIE, (GWP)2t, Waterloo Campus - Amorphous silicon-carbon alloys have been produced in a high vacuum system (base pressure vl.5 x 10- - Pa). Thin films were deposited using a resistance heated source. Some electrical, optical and structural properties of the samples have been studied and these results will be reported. These films appear to have potential for use in thin film devices.

*Supported by DSS 01SX-31155-2-2718.

^Guelph-Waterloo Program for Graduate Work ir Physics.

BA5 Thermal Expansion, Ultrasonic Velocity and Attenuation Measurements in TiS2< T i S e ^ a n d TiSp. SS e l. 5» Μ. H. JERICHO and A. M. SIMPSON, Dalhousie University,A. CAILLE, Université de Sherbrooke, and Y. LEPINE, Université de Montreal. - Measurements have oeen made of the velocity and attenuation of ultrasonic plate mode waves in TiS2, TiSe2 and TiSo.5Sei.5 between 4 K and 300 K. TiSe2 exhibits large anomalies associated with the occurrence of a charge density wave transition near Tc = 200 K. Measurements of the expansion coefficient and of the a-axis uniaxial stress dependence of Tc have also been made, and these measurements, together with other data in the literature, are discussed in terms of the Ehrenfest relationships. The temperature depend­ence of the velocity in TiSe2 below T c is accounted for by an anharmonic contribution and an electron-phonon contribution which reflects the opening up of energy gaps on the Fermi surface by the charge density wave. Above Tc» the velocity changes are found to be affected by fluctuations over a wide temperature range and it is suggested that these fluctuations are associated with the phonon mode near the L point of the Brillouin Zone softening as Tc is approached.

BA6 Ground State Properties o f Rare Ga» Mono­layers Adsorbed on Graphite.* N.D SHRIMPTON andB. BERGERSEN, Department o f Physics, University o f British Columbia and B. JOQS, Department o f Physics, Simon Fraser University.- We analyse a nuntoer of possible periodic superlattice configurations of a rare gas monolayer on graphite. The solutions are obtained by an analysis of the Fourier conponents of the distortions from an average hexagonal configur­ation. Our model js a generalization of a previous continuum approach , to allcw for inclusion of an­harmonic effects and corrections due to the discrete­ness of the lattice.

Shiba H., J. of Phys. Soc. Japan 48,211 (1980)

*Supported by NSERC.

BA7 Long-Wavelength Phonons in Metallic Layered Stj^ucture^. W. G. McMULLAN and J. C. IRWIN, Physics Department, Simon Fraser University, and J. L. FELDMAN, Naval Research Laborato r y , W a shington , P .C. -

A valence force field lattice dynamics model has been used to investigate the long wavelength phonons in a number of layered-structure metals. Expressions have been obtained in closed form for the zone center phonon frequencies in terms of six parameters, four of which are utilized. Results obtained from Raman-scattering experiments on 2H-NbS2 , 3R-NbS2 , 2H-TaS2 and 2H-TaSe2

have been used to evaluate the model parameters for each compound. This model has also been used to assist in the interpretation of Raman spectra obtained from Ag~ intercalated 2H-TaS2 . In this case the zone boundary phonon frequencies of the pure compound are obtained from the full dispersion curves and compared to the observed zone-folded phonons of the intercalated compound. Finally a thermally induced, reversible interpolytypic transition between 2H-NbS2 and 3R-NbS2 has been observed.

BA8 Lattice Dynamics of AgxTiS, by Raman Scattering. K. K. BARDHAN and J. C. IRWIN, Physics Department~Simon Fraser University - A careful investigation using Raman scattering of Titanium t isulphide intercalated with silver (AgxTiS2 ; 0<*<.4?) revealed more structure in the zone center normal modes than hitherto reported^)·It has been possible to identify those modes which are present irrespective of the composition of silver and hence could be attributed to arise from the inplane zone-folding. Further consequences of staging will be discussed. Zone-folding will be discussed in a concrete fashion using the results of a lattice dynamical calcu­lât ion.

^R. Leonelli, M. Plischke and J. C. Irwin,P R L . 45, 1291 (1980).

BA9 De Haas-van A l phen Effect of Stage I SbCls - HOPG Compound.* H. ZALESKI, P. UMMAT and W. R. DATARS, McMaster University - Highly Oriented Pyrolytic Graphite (HOPG) was intercalated by submersing 5 mm x 3 mm x 0.2 mm pieces in SbCl5 at a temperature of 220 C for four days. X-ray diffraction showed pure stage 1 with an identity period Iç of 9.40 Â. The de Haas-van Alphen (dHvA) studies showed one dominant dHvA oscillation with a frequency of 1205 T and a cyclotron mass m*/m0 = 0.28. There were laso two weaker oscillations with frequencies of 1107 T and 1025 T. This frequency spectrum is much simpler and more reproducible than higher stages of the same compound in which the intercalant is thought to consist of numerous ions and molecules. The results are therefore useful for comparison with band structure theories of simple intercalated compounds.

* Research supported by the Natural Sciences and Engineering Research Council of Canada.

BA10 Structural Transitions in A g vT i S , . G. JACKLE and J. C. IRWIN, Physics Department, Simon Fraser Uni­versity - Calorimetric experiments have been carried out on Ag-intercalated powders of TiS2 . No evidence of the intercalate order-disorder transition at 260K is found.A strong peak has been observed at about 445K, however, for all AgxTiS2 samples with ,15<*<^45. The results of X-ray diffraction and electron microscopy experiments carried out in these compounds in the same temperature regions are also reported. In particular, an X-ray diffraction study of the intercalate order-disorder transition has been carried out and the results are compared to similar data obtained previously from intercalated single crystals.

ROOM 136

BIOPH YSIC S/L IQ V ID S

BB1 a Monte Carlo Simula tion of Bilayers of Satu­rated Phospholipids containing Cholesterol T. L00KMAN, D.A P INK,1 N. JAN, M.J. ZUCKERMANN* and F. DE VERTEUIL*. Theor. Phvsics Inst , St. Francies Xavier University, Anrignnish, NnvaSrntia ;lnH*Physics Dept., McGill Univer­sity, Montreal, Quebec. - We have used Monte Carlo techniques to study equilibrium properties of a 2-di­mensional lattice model with nearest neighbour interac­tions, of a lipid bilayer containing cholesterol. Sites of a triangular lattice can be occupied by either lipid chains, which have 3 states (ground g, intermediate I, excited e) available to them, or by a cholesterol mole­cule possessing a single state. We assume that choles­térols interest attractively with lipids in state I and repel those in states g and e. Both the Glauber and Kawasaki approaches are used together with an energy barrier to lateral displacement Results will be pre­sented for phase diagrams, thermodynamic quantities and mean square displacements <r^> as a function of temper­ature and concentration, and compared to studies of DPPC-cholesterol bilayers. Work supported by NSERC of Canada and University of Virginia.

^Presently at: Dept, of Pharmacology. UVA. Ch'ville.VA

BB2 NMR Investigation of Molecular Dynamics in Wet Cellulose. J. WALLACE, F. KAKULE, A R SHARP andH. PEEMOELLER, Dept of Physics, Univ of New Brunswick - The temperature dependence of the NMR spin-lattice and spin-spin relaxation times of protons and deuterons were investigated in hydrated cellulose samples. Measurements were made at a resonance frequency of 30 MHz for both nuclei and at temperatures ranging from 360°K to 140°K. The data can be adequately described using a 3-phase model. At room temperature physical exchange occurs between two of these phases at an exchange rate that is intermediate between that for fast and slow exchange The molecular dynamics of the water and cellulose molecules and the significance of magnetic coupling between the water and cellulose protons will be discussed.

BB3 Study of Protein - Water Interactions usinq the NMR Line Shape - Relaxation Correlation ApproachF. KAKULt, H. PEtMUtLLER and A .R. Sharp, Dept, of Physics, Univ. of New Brunswick - The behaviour of the recovery of the longitudinal magnetization in wet lysozyme was investigated by combining the line shape-relaxation correlation approach with the selective inversion of the magnetization. All measurements were performed at room temperature and at a frequency of 40 MHz The results conclusively show that at this temperature the lysozyme protons and the water protons are strongly coupled and that the water is the major relaxation sink in this sample. Magnetization transfer rates between the lysozyme and water are derived and used to illucidate the cause of the apparent non exponential longitudinal recovery curves often observed in hydrated protein systems.

BB4The 9 GHz Complex Permittivity of Water at 293 K .*

G. McAvoy and H.A. Buckmaster, Dept, o f Physics, University of Calgary - The complex permittivity of water at 9 GHz has been remeasured using a new instru­mentation system. This redetermination has resulted in improvement in the accuracy by a factor of at least 20

22

for the permittivity and of 6 for the loss. It is found that €' = 62.26(4) and = 31.57(5) for water at 293 K. These values are compared with those reported in the literature. Details of the instrumentation system will be g ive η .*Supported by a NSERC research grant.

BB5 NMR Line Shape-Relaxation Correlation Study of Molecular Dynamics durine Cement Hydration and Setting.J.C. MacTAVTSH, L.J. SCHREINER and M.M. PINTAR, (GWPp, Waterloo Campus^ - With the two dimensional NMR method it is possible by a graphical analysis of the proton magnetization recovery along the recovery time axis at high magnetic fields, or of the magnetization decay at low fields, to resolve the heterogeneous free induction decay into components, thus correlating relaxation to line shape, whenever the relaxation times of the components differ substantially.

With this method the proton magnetization of cement paste was resolved into three distinct components in a nondestructive way. The formation and evolution of Ca(0H)2 crystals, of micropore water and of gel phase was monitored simultaneously and continuously. It will be proposed that the new information supports strongly the diffusion model of hydration.

tGuelph-Waterloo Program for Graduate Work in Physics.

BB6 E l e c t r o n i c S t a t e s in L i q u i d and A m o r ­p h o u s Fe . * L.E. B a l l e n t i n e , S.K. B o s e and J.E. H a m m e r b e r g , D e p t , o f P h y s i c s , S .F .U . ,B u r n a b y ,B . C . V 5 A 1S - It has o f t e n b e e n a s s u m e d that e l e c t r o n i c c o n d u c t i o n in l i q u i d and a m o r p h o u s t r a n s i t i o n m e t a l s is d o m i n a t e d by a s m a l l n u m b e r o f m o b i l e s t a t e s , w h i l e the m a j o r i t y of the s t a t e s a r e p r a c t i c a l l y i m m o b i l e . To t est the v a l i d i t y of s u c h a s s u m p t i o n s we h a v e c o m p u ­ted the e l e c t r o n i c d e n s i t i e s of s t a t e s and s p e c t r a l f u n c t i o n s f o r m o d e l s of l i q u i d and a m o r p h o u s Fe. T h e s p e c t r a l f u n c t i o n s , w h i c h m a y or m a y not h a v e s h a r p p e a k s , g e n e r a l i z e the c o n c e p t of b a n d s t r u c t u r e to d i s o r d e r e d p h a s e s . We f i n d t h a t i d e n t i f i a b l e s b a n d s and d b a n d s e x i s t , a l t h o u g h t h e y are not s h a r p . T h o u g h the s s t a t e s a r e m o r e m o b i l e t h a n the d s t a t e s , the c o n d u c t i v i t y is d o m i n a t e d by d s t a t e s b e c a u s e of t h e i r m u c h g r e a t e r d e n s i t y .

BB7 Determination qf_ Electron-ion Pseudopotentials for Liauid Metals from Structure Factor Data. C.DHARMA-WARDANA, G. AERS and ROGER TAYLOR, National Research _Council of Canada - A method of inverting a given structure factor of a liquid metal using a hypernetted-chain equation containing bridge diagram contributions Is presented. The method proceeds from a trial ion-ion potential constructed from a non-local pseudopotential which Is optimised to reproduce the experimental structure factor to high accuracy. The resulting pseudopotentials and calculated physical properties of several liquid metals will be presented.

BB8 Brillouin Asymmetry Induced by a Temperature Gradient. R. PENNEY, H. KIEFTE AND M. J. CLOUTER, Memorial U. of N fld. - Recently a number of theoretical predictions have been made concerning the nature of fluctuations in fluids about simple nonequilibrium states. Such analyses have been undertaken using linear fluctuating hydrodynamics, nonlinear response theory and kinetic theory with the same general result that when a

fluid is brought out of equilibrium by a steady temper­ature gradient an asymmetry in the intensities of the two Brillouin peaks results. This is due to broken time reversal symmetry. The effect, however, becomes measur­able only for high temperature gradients and very small scattering angles 1°). Unfortunately the only ex- perimentsl to test this prediction were carried out under conditions where the (water) sample dimensions were small compared to the mean-free path of the acous­tic waves. The effect was observed but agreement with theory was poor. In the present work a larger sample was used to minimize the finite size effects. The re­sults show good agreement with theoretical calculations and boundary effects are clearly evident.

^Beysens, D . , Garrabos, Y. and Zalczer, G . , Phys. Rev.Lett. 45, 403 (1980).

ROOM 136

μ SR, PO SITRO N ANNIHILATION

BC1 Muon Spin Relaxation Studies of Extremely Concen­trated Paramagnetic Solutions, KENNETH E. NEWMAN, KIM M. ADAMSON-SHARPE , JEAN-CLAUD BRODOVIi’CH AND PAUL W. PERCIVAL, TRIUMF and Chemistry D eptartm e n t , Simon Fraser University - Nuclear magnetic resonance studies of para­magnetic ions in solution have been extremely important in contributing to our understanding of both structural and dynamic aspects of electrolyte solutions. However, due to the large relaxation effects observed, studies are limited to very dilute solution. The positive muon is an elementary particle whose chemistry reflects that of the proton and like the proton, it has spin 1/2 and hence an associated magnetic moment. In aqueous solution, the muon substitutes the proton predominantly and using particle physics counting techniques, one can measure the muon magnetic relaxation rates analogous to those obtain­able by conventional nuclear magnetic resonance. Relaxa­tion rates between ΙΟ^-ΙΟ' s“ * are accessible which are typically those exhibited by very concentrated solutions of paramagnetic ions. The great utility of this tech­nique is the ease with which one can vary the applied magnetic field, thus allowing ready evaluation of correlation times.

BC2 Atomic Capture Ratios for Muons :.n Oxides.* S. STANISLAUS, F. ENTEZAMI, D. GARNER and IT. F . MEAS D A Y , University of British Columbia - The atomic capture ratios for u” in oxides has been remeasured using the lifetime technique. The results are somewhat different from our earlier values^, but more consistent with the mesic X-ray measurements. For the new data, more infor­mation was obtained on the carbon background, and the time t = 0 was defined more precisely. It has been noticed that the capture ratio depends monotonically on density, whereas the Z dependence is periodic. This effect will be discussed.

Suzuki, T. et al., Phys. Lett. 95B, 202 (1980).

*Supported by the Natural Sciences and Engineering Research Council of Canada.

BC3 Spin R e l a xation in YRh,,B, and SmRh,B,*. E.J. ANSALDO**, D.R. HARSHMAN, J. BREWER, TRIUMF & U B C , C.Y. HUANG, LASL***, K. CROWE, S.S. ROSENBLUM, LBL***. _ The relaxation behaviour of the u+ SR signal has been studied in YRh^B^ (non-magnetic superconductor below Tc *11.2 K) and SmRh^B4 (superconductor below Tc*2.7 K and antiferromagnetic below Τ ν *0.9 K ) . Two exponentially relaxing signals were found in the latter at temperatures

T<Tfj. For Tn <T<4 K the signal is a single exponential with a mild critical behaviour. For both S mRhMB M, at T£30 K and Y R h ^ , at 11.2<T<100 K, the relaxation has a shape (Kubo-Toyabe) typical of stationary random dipolar fields acting on the muon.

*Supported by NSERC, Canada**0n leave from the Univ. of Saskatchewan.***Supported by the U.S. DOE.

BC4 Behaviour of M uonium on Silica S u rfaces*. D.R. HARSHMAN, J.H. BREWER, M. SENBA, TRIUMF & U B C , R. KEITEL, D ept, of Phys., U of E rlangen-Nurnberg, E.J. ANSALDO**. - The behaviour of muonium on the surface of finely

divided silica powder (mean grain diameter 70 angstroms) has been studied as a function of the surface concentration of hydroxyl groups. The temperature dependence of the Mu relaxation rate in transverse field was measured for sam ples prepared with 0%, 50% and 70% of the surface hydroxyl groups removed over the temperature range 4K < T < 300K. The relaxation rate shows a distinct maximum at 25K and a minimum at about 16K as the concentration of surface hydroxyls is reduced. A three- state non-equilibrium model describing the surface diffusion, trapping and desorption of muonium from the silica surface is used to interpret the data. In addition, gas adsorption Isotherm studies on the silica samples were performed with ^He at 6K concomitant with measurements of the dependence of the muonium relaxation rate on the percent surface coverage.

*Supported by NSERC, Canada.*0n leave from U of Saskatchewan.

BC5 Muonium Formation In Oxide Insulators: SÍO2, Ge00 , Sr~T10? , ZrSiO^ and T ToJT D.P. SPENCER, D.G. FLEMING, J.H. BREWER AND M. SENBA, TRIUMF and Depts. of Chemistry and Physics. U. of British Columbia. Vancou­ver - Searches have been conducted for Mu In various oxide Insulators in predominantly crystal environments. We have not been able to detect any Mu in either SrTIO^, ZrSiO^ or TÍO2, but there is a tiny signal (~2%asymmetry) in both a fused sample and In a hexagonal single crystal, but no signal in a tetragonal crystal. The hexagonal form Is the same as quartz, and Indeed one would at least naively expect SÍÚ2 and GeO^ to produce similar amounts of Mu. In TiC^there Is a 100% signal but in both SrTiÛ3 and ZrSiO^ there is a loss in muon asymmetry. The most complete data has been obtained in SrTlO^, which undergoes an antiferroelectric phase tran­sition at ~30 K. In fact we observe a minimum In the amplitude at this temperature but no muonium. In quartz Itself, long the prototype solid for copious Mu forma­tion (now in fact revealed to be clearly anomalous be­haviour) we have searched for the 29Si super-hyperfine Interaction at low temperatures In a zero field. There is a hint of a signal and results of our current data analysis will be presented.

BC6 Muonium in Single Crystals of Ice.P.W. PERCIVAL, J .- C . RR0D0VITCH, S . LEUNG andK.E. NEWMAN, TRIUMF and D e p t . of Chemistry, S F U . - We have studied muonium in single crystals of H 2O and D 2O over a wide range of temperatures. All previous studies of Mu and H in ice have been with polycrystal1 ine sam­ples. We discovered a two-frequency precession signal at low fields where degenerate transitions are expect­ed*. The phenomenon is just that found by Brewer et al. in quartz^ and is due to a previously unknown aniso­tropy of axial symmetry in the muonium hyperfine inter­action. This interpretation was confirmed by orienta­tion dependence of the frequency splitting and observa­tion of a single zero-field frequency. By analogy with the quartz results we postulate that Mu diffuses along the c-axis channels of the ice lattice. H is expected

to behave in the same way, but there is no analogous data. Accordingly, we have undertaken a thorough study of muonium spin relaxation rates as a function of temperature in both H2O and D2O crystals.

P.W. Percival et aj., Chem. Phys. Lett. 93 (1982) 366.J.H. Brewer et al., Hyperfine Interactions 8 (1981)375 and 405. ~~

BC7 Perturbed Directional Correlation Studies of Cd-111 Gamma-rays in Gallium. G.R. DeMILLE, D.L.LIVESEY , and G.J. GYAPONG, Dept, of Physics, U.N.B., Fredericton - Time differential PDC measurements on the CD-111 gamma-rays emitted following the electron capture decay of In-111 in gallium metal indicate that, when the sample is suitably annealed, the indium atoms occupy a substitutional site in the host α-Ga lattice. The measured quadrupole interaction frequencies give for the electric field gradient (uncorrected for antishielding effects) at the substitutional site V zz = 6.84 x 102 - V/m2 at 300 K with an asymmetry parameter η = (Vxx -Vyy) / V 2Z = 0.210, consistent with other determinations. Measurements at 77 K confirm the expected T1*3 depend­ence for V zz. A second component in the perturbation factor observed for some samples is consistent with an interstitial indium atom in the relatively open a-Ga structure in which the radioactive atom appears to rotate freely within the host lattice. In one sample a much lower interaction frequency is observed which seems to arise from an amorphous form of gallium exhibit­ing some local structure suggestive of 3-Ga.

BC8 Vacancy Formation Energy In Thorium by Positron Annihilation. S.M. KIM, J.A. JACKMAN and W.J.L. BUYERS, Atomic Energy of Canada Limited. Chalk River, D.T. PETERSON, Ames Lab·. Iowa State University - We have carried out measurements of the temperature dependence of the positron annihilation peak coincidence rate In thorium between 20°C and 1460°C. A very gradual S~shaped rise due to positron trapping at vacancies was observed above 700°C. The peak rate did not change across the fee to bcc phase transition at 0 1345°C, Indicating saturation trapping at this temperature. A standard trapping model analysis of the data, with certain constraints on the trapping parameter, indicates that ct-thorium has a vacancy formation energy Ef of1.28±0.23 eV. The value agrees with “ 1.25 eV obtained from the seml-empirlcal threshold temperature method. In addition, since positron trapping In 0- thorium Is already saturated at β 1345°C we also deduce that the vacancy formation energy In 0-thorium Is equal to or smaller than that in orthorium. A slight decrease In peak rate has been observed between 20°C and 240°C and this may be associated with the nitrogen impurities.

BC9 Anisotropic Positron Annihilation in Single Crystalline. J.A. JACKMAN, S.M. KIM and W.J.L. BUYERS, Atomic Energy of Canada Limited, Chalk River - Thepositron annihilation peak coincidence rate has been measured from 100 K to 660 K in single crystals of zinc oriented to observe momentum distributions In the [1010] and [0001] directions. In addition, full angular corre­lation curves were measured at 100 K, 340 K and 600 K for both orientations. The peak coincidence rate exhibited an anisotropy that peaked at the threshold temperature for vacancy formation (400 K). Above this temperature the momentum distributions became more Isotropic as positrons were trapped at vacancies. The angular corre­lation curves at 340 K showed that the smearing near the Fermi momenta Is much larger than that expected from the positron thermal motion, and is consistent with positron localization In a region 12 Â in diameter. At tempera­tures above 600 K, where saturation trapping occurred, a

24

positive slope to the peak count rate versus temperature was observed. Its inclusion in the trapping model enables an improved estimate of the vacancy formation energy, Ef- 0.59 ±0.05 eV to be obtained, independent of crystal orientation.

ROOM 144

ATO M IC AND MOLECULAR P H YSIC S

BDl Stable Variational Calculations with the Dirac Hamiltonian.* W. E. BAYLIS and S.J. PEEL, University of Windsor - Relativistic one-electron problems fre­quently suffer from variational instability associated with the absence of both upper and lower bounds to the eigenvalues of the Dirac Hamiltonian H^. Such insta­bility is trivially avoided if the square H ^ is used rather than H to find energy eigenstates and eigenva­lues. There are then no spurious roots, and true energy bounds and reliable wave functions are readily obtained. Sample calculations for H-like systems are presented.

* Supported by Natural Sciences and Engineering Research Council of Canada.

BD2 New Line Identifications in the Neonlike

Atoms* SIDNEY 0* KASTNER, U. of British Columbia -5 5 5Improved classifications of 2p 3p - 2p 3s and 2p 3d -

2p^3p transitions are presented, particularly for the

line pair 2ρ^3ρ(^>0 ) “ which has been

misidentified in the literature. The forbidden magnetic

dipole transition 2p ^3s (^Pq - *-,j $ recently

identified in Fe XVII as a far ultraviolet coronal line,

is further located in Ca XI, Cr XV and Kn XVI as the

origin of three observed coronal lines.

BD3 z Dependence_of O s c i l l a t o r S trengths in the Be, A1 and Ga isoelectronic sequences.* K. AASHAMAR, U . ofOslo, T.M. LUKE and J.D. TALMAN, U. of Western Ontario - A study of the Z dependence of oscillator strengths has been made for the Be, Al, and Ga sequences using the Multiconfiguration Optimized Potential M o del.1 In the latter two sequences, we consider transitions from the2P ground state to * 2S and 2D excited states. Owing to the plunging in energy of certain levels as Z increases, there are strong variations in the mixing coefficients leading to irregularities in the Z dependence of the os­cillator strengths. In the Be sequence, a relativistic calculation of the "2s2 1S e -2s3p'/P 1°" intercombination line shows a strong but smooth Z dependence owing to the increasing singlet-triplet mixing with increasing Z. For each sequence, the present work will be compared with recent experiment and other theory.

♦Supported by the Norwegian Research Countil for Science and the Humanities, Nordita, and NSERC, Canada 2K. Aashamar, T.M. Luke and J.D. Talman, J. Phys. B 12, 3455 (1979).

BD4 Radiation Damping in the Pilot Wave Interpretation of Quantum Mechanics.* M.C. ROBINSON*, C.E. AVELEDO,L.A. LAMEDA, and D. BONYUET-LEE, Departamento de Fis ica, Universidad de Oriente; Cumanà, 6101, Venezuela - To avoid the internal contradiction in the pilot wave inter­pretation inherent in the assumption of a changed parti­cle moving in a closed orbit without radiating, it is proposed that the wave functions, ψ„(τ), corresponding

to stationary states, be real , implying that the particle is stationary. If the effect of radiation damping is included, the Hamiltonian contains the nonlinear term,

iHt /2 d^£n[4'{r,t)/lF*(r,t]/dL't resulting in the stability of the stationary states. The underdamped normal vibra­tions obey Bohr's frequency condition.

*0n sabbatical leave, Physics Department, McGill Univ.

BD5 Beam-foil spectroscopy of fourth and fifth row elements.* E.H. PINNINGTON, W. ANSBACHER, J.L. BAHR,P. MEENAKSHI and J.A. KERNAHAN, Physics Department, University of Alberta - A program to study the spectra of fourth and fifth row elements excited by the beam- foil interaction has been underway for several years. Currently the elements gallium, germanium, krypton, tin and zinc are being studied, with particular emphasis on ions which are members of the C u l , Z n l , Agi and Cdl isoelectronic sequences. Radiative lifetimes obtained from beam-foil decay curves are used to derive absorp­tion f-values for the resonance transitions of the ions in these sequences. It is known that the reliability of the f-values so obtained can be adversely affected by cascade-repopulation of the upper state involved in the transition being studied. In this paper we discuss experimental and analytical methods for minimizing this potential source of error.

•'Supported by N.S.E.R.C. and the Province of Alberta.

BD6 Etude du fer, du cobalt et du nickel par la spectroscopie d'ions rapides. C. JACQUES, J.-P. M O ­REAU et E.J. KJNYSTAUlAS, univ. Laval, Québec - Nous avons fait l'étude des ions métalliques, ter, cobalt et nickel, par la spectroscopie d'ions rapides. Des faisceaux d'ions de quelques dizaines de nanoampères ont été obtenus par la pulvérisation cathodique du canal de sortie de la source radiofréquence dans le termi­nal d'un accélérateur Van de Graaff. Nous avons m e ­suré des spectres de fer, de cobalt et de nickel hautement ionisés dans l'ultraviolet lointain, 150 I 310 8 et 1260 à 1700 8 . Seize vies moyennes ont également été mesurées dans le Fe IV-VII, trois dans le Co VI-VIII et deux dans le Ni VII-VIII. Nous comparons nos résultats avec d'autres mesures.

BD7 Collision-Induced Absorption of H,_in the First Overtone Region. E. VAN NOSTRAND and S.P. REDDY, Memorial U. of Nfld.- Spectra of collision-induced absorption of normal H„ in the pure gas at /7, 201 and 295 K in the 2-0 region were recorded with c 2 m absorption cell for gas densities in the range 160 to 360 amagat. From the measured integrated absorption coefficients, the binary and ternary absorption coefficients have been determined. Analysis of the experimental profiles, carried out with the available theoretical matrix elements of the quadrupole moment, polarizability and its anisotropy, shows that the calculated intensities are systematically too high. Reduction of the matrix elements of the quadrupole moment by a factor 0.68 for the av=2 transitions gives a satisfactory agreement between the calculated and observed profiles. Spectra of the double transitions, Sj(J)+S,(J) and which fall on the high

wavenumber wing of the main transitions were also recorded in the pure gas at 77 K for gas densities in the range 640 to 940 amagat. Separation of these transitions from the underlying wing of the main transitions enabled us to obtain a measure of the contribution of the anisotropy of the polarizabi1ity.

BD8 Emission Spectra of CN in the Vacuum Ultra­violet. K.P. HUBER, Herzberg Inst, of Astrophys., Nat. Res, Council of Canada - High resolution emission spectra from a radio-frequency discharge through streaming Dure HCN have been studied in the region 1800-2100 A. Of several new transitions the most inter­esting ones originate in three previously unidentified 2Π vibronic levels; they provide clear evidence for a strong homogeneous perturbation of the higher D2J1 levels by a more strongly bound state, probably Η2Π. The new analyses confirm the results of ab initio calculations^ which predict the existence of no more than two 2J1 electronic states, in addition to A2J1, at energies of less than 8 eV.

H.F. Schaefer and T.G. Heil, J. Chem. Phys. 54, 2573 (1971).

BD9 Infrared Absroption in Proton-irradiated Solid Hydrogens. R. L. BRUUKS, M. SELEN, J. L.HUNT, J. R. MacDONALD and J. D. POLL,Dept, of Physics, Univ. of Guelph, J. C. WADDINGTON, Deüt. of Physics, McMaster Univ. - infrared absorption spectra in the fundamental band have been acquired for ^ a n d HD with the sample irradiated by 15 MeV protons. Ionization of the sample by the beam causes additional spectral features to appear and these have been studied as a function of beam current and sample temperature in the range of 4.2 to 10 K. The presence of trapped electrons, inferred from these studies, has been confirmed by observing the direct infrared spectrum of such electrons. The time scale for growth and decay of the spectral features is a sensitive indicator of the mobility of ions and trapped electrons in the sample, and is strongly temperature dependent. The technique may have application in a range of molecular solids as a method of providing detailed information concerning ions and electrons in insulators

BD10 Very-high-resolution study of Fine & HyperfineStructure in N ?·* . S.D. ROSNER, T.D. GAILY, & R.A.HOLT*j

of Physics, U. of Western O n tario - The fine and hyperfine structure of 1‘,N 2+ and N 2* have been studied using Doppler-tuned laser fluorescence spectroscopy. Observation of many rotational lines in the (0,1) band of the B 2Zu+ - X2Ig+ first negative system gives spin- rotation and magnetic hyperfine constants which are in very good agreement with ab i n i t i o calculations, and resolve discrepancies discussed in the context of an earlier preliminary measurement. A laser-rf double resonance study of the X-state fine and hyperfine structure will also be discussed with special reference to measurement of the electric quadrupole coupling constant in lt*N2+ .

Currently on leave at the Clarendon Laboratory, U. of Oxford, Oxford 0X1 3PU, U.K.

S.D. Rosner, T.D. Gaily, & R.A. Holt, Phys. Rev. A26, 697 (1982).

BD11 Dipole Moment of the FO Radical.A.R.W. McKELLAR, Herzberg Institute of Astrophysics,N« R .C.C., Ottawa - It has long been a puzzle as to why the FO molecule could not be detected by means of microwave or gas phase electron resonance spectroscopy even after extensive study of the related group VI-VII diatomics (CIO, BrO, SF, SeF, e tc.). The recent observation^ of a strong vibrational spectrum of FO using laser magnetic resonance (LMR) demonstrated that production of the radical in the gas phase was not especially difficult, and suggested that a small permanent dipole moment might be responsible for the absence of rotational or EPR data. By applying a moderate (1.4 kV/cm) electric field while observing saturated absorption signals in the LMR spectrum, it has now been possible to measure the dipole moment.The values obtained are amazingly small (0.004 D for v = 0 and 0.025 D for v = 1 ) and thev fully explain the previous lack of success in observing spectra in the microwave region.

A.R.W. McKellar, Can. J. Phys. 57, 2106 (1979).

BD12 Temperature Dependence of Collision Induced Absorption in Nitrogen.* A. ANDERSON, I.R. DAGG,N.W.B. STONE, (GWP)4·, Waterloo Campust andL.A.A. READ, Wilfrid Laurier University - The far infrared collision-induced absorption spectrum of gaseous nitrogen has been accurately measured over the temperature range 227-343°K. A special emphasis has been placed on acquiring consistent data in the low frequency range below 60 cm“ ‘. This has been accomplished by using microwave cavity techniques, a far infrared laser system, and Fourier transform interferometric spectroscopy. The results, which have been analyzed using a recent theory of quadrupole induction, provide an improved value for the quadrupole moment, which is constant over the temperature range investigated.

♦Supported by NSERC of Canada.

tGuelph-Waterloo Program for Graduate Work in Physics.

Far Infrared Spectra of Methanol and Methyl- amine.* R.M. LEES and M.S. MALGHANI, Physics Dept.,U. of New Brunswick - Analysis will be presented of the far infrared spectra of C H3OH and CH3NH2 from 50 - 125 cm-l, obtained at 0.005 cm“ l resolution on Dr. J.W.C. Johns' Bomem Fourier transform spectrometer at the Herzberg Institute of Astrophysics. The Q branches in the CH3OH spectrum have been assigned in the ground torsional state for K values from 5 to 11, and the corresponding R branches up to J values of typically 30. Various Q and R branches have also been assigned in higher torsional states. For CH3NH2, most of the R branches with K from 7 to 14 have been identified for A a and E a torsion-inversion symmetries, and extrapolated to give Q-branch origin frequencies. Results of filtered least-squares fits to molecular and distortion- al parameters will be reported.

*Work supported by NSERC.

BD14 Lvman and Werner Band Excitation of .* K. BECKER, W. VAN WIJNGAARDEN and J.W. McCONKEY,"Phys_J.cs Department, University of Windsor - The Lyman (Β^Σ -+ Χ^Σ ) and Werner (C^n* - Χ^-Σ+ ) emissions of have bee$ studied in a crossed el§ctron~gas beam arrangement using a Seya-Namioka 0.5 m monochromator to disperse the resulting radiation. Absolute cross-sections and

26

their variation with incident electron energy over the range threshold to 500 eV have been obtained. Cascade effects have been considered in detail.

* Supported by the Natural Sciences and Engineering Research Council of Canada.

BD15 Diffusion inélastique d'électrons lents sur les

molécules CO, et SO,.* .D. ROY, B. LECLERC, J. DELWICHE+ et M.-J. HUBIN-FRANSKIN', CRAM et Univ. Laval - Nous avons récemment réalisé une série de mesure de pertes d'énergie d'électrons dans les gaz de C02 et S02 , au moyen d'un spectromètre électronique de haute résolution. En particulier dans C02 , nous avons étudié les séries de Rydberg qui se manifestent dans la bande d'énergie 11-14 eV, convergeant vers la première limite X 2Π π . En plus des bandes de Rathenau "fortes" et "larges" entre 11.5 eV et 13 eV, nous observons les séries "principale 1" et "mineure 1", et une troisième dont le premier mem­bre est situé à 12.307 eV. D'autre part, lorsque l'ex­citation se produit à une énergie voisine du seuil, une nouvelle série se manifeste, dont le premier membre se­rait à 11.142 eV. D ’après le défaut quantique, il s'a­girait d'une orbitale du type ηρσ ou ηρπ, impliquant une transition interdite par la symétrie. Des résultats se­ront aussi présentés pour S02 .

* Subventionné par le Fonds FCAC et le CRSNG/NSERC.

t Adresse permanente: Univ. de Liège (Belgique).

BD16 The Valence Shell and Chlorine 2p Electronic Spectra of HCI by High Resolution Electron Energy Loss * 1 2Spectroscopy*. S. DAVIEL and C.E. BRION, Dept, of Chemistry, U . B. C._j_ Vancouver , B.C. , Canada. - The design and operation of a new, differentially pumped, high resolution electron energy loss spectrometer^ will be described. Using this Instrument the valence shell electronic spectrum of HC£ has been obtained,2 from 5-19 eV at 3 KeV impact energy with an energy resolution of0.035 eV and a scattering angle of zero degrees. The chlorine 2p (L2 3) excitation spectrum2 has also been measured from 1$9-213 eV at a resolution of 0.11 eV. An interpretation of these spectra will be presented. More recent measurements and also the design of a new position-sensitive detector for this spectrometer, comprising microchannel plates and a phosphor screen with fibre-optic coupling plate to a photodiode array will be discussed.

1 S. Daviel, C.E. Brion and A.P. Hitchcock, to be published.

2 S. Daviel, C.E. Brion, to be published.

* Supported by NSERC

BD17 Measurement of Orbital Electron Momentum Distri­butions by Binary (e,2e) Spectroscopy. K.T. LEUNG andC.E. BRION, Dept, o f Chemistry, U. of B .C., Vancouver, B.C. Canada - A high momentum resolution binary (e,2e) spectrometer [1] is used to measure valence shell binding energy spectra and individual orbital electron momentum distributions for the noble gases [1], H 2 [2], F 2 , CF^ and C02 [3]. The momentum distribution (ψ2(ρ)) provides a sensitive test for SCF wavefunctions and a direct experimental "view" of individual orbitals. The techni­que shows considerable promise in experimental quantum mechanics. Computer generated density maps and 3-D orbital visualization of theoretical wavefunctions in both position and momentum space are used to interpret the results and to develop understanding of chemical bonding in momentum space. The process Η + H — ► H 2 is

studied by means of density and density difference maps in momentum space as a function of internuclear separa­tion. Binary (e,2e) measurements for H2 1σ are also compared with results from Compton scattering [4].

[1-3] K.T. Leung and C.E. Brion, to be published.[4] J.S. Lee, J. Chem. Phys. 66, 4906 (1977).

BD18 Scattering of A toms from Overlavers. JEREMY M. HUTSON and CAREY SCHWARTZ, Department of Chenistrv, U. of Waterloo, Waterloo, Ontario N2L 3G1 CANADA - We have performed accurate close-coupling calculations for the elastic scattering of a He beam from a monolayer of Xe on the (0001) face of graphite, using realistic atom- surface potentials based on pairwise additivltv and the known He-Xe pair potential. Good agreement with the experimental data of Bracco et al. is found ::or both diffractive scattering and selective adsorption resonances. The sensitivity of the resonance data to small changes in the potential has been investigated; in particular, the surface scattering data distinguish clearly between two pair potentials which both reproduce the gas-phase data well. The possibility of obtaining information on many-bodv contributions to the atom- surface potential will be discussed.

BD19 A New Improved Interatomic Potential for Ne-Ar. R.A. AZIZ, (GWP ) 2 , Waterloo Campust - Literature interatomic potentials for the Ne-Ar interaction are critically assessed insofar as their ability to predict dilute gas bulk properties (virial and transport coefficients) and microscopic properties (differential and total collision cross sections). A new improved interatomic potential of the HFD-C type is proposed.

fGuelph-Waterloo Program for Graduate Work in Physics.

BD20 yt Charge Exchange and Muonium Formation in Vapors, D.J. ARSENEAU, D.M. GARNER, D.G. FLEMING AND M. SENBA, TRIUMF and Dept, of Chemistry. U. of British Columbia - It has long been of interest to measure the residual polarization of incident positive muons that thermalize in vapors either as muonium (PM ) or in dia­magnetic environments (Pp) in order to compare with (proton) charge exchange data and with the corresponding fractions seen in liquids.1 From the charge exchange model we would expect essentially 100% Mu formation in all cases. The results are dramatically different from those in liquids; in all the vapors studied except CCl^, Pf«j ~90% vs. ~20% in liquids and correspondingly Pp ~10% in the vapors vs. ~60% in the liquids. In addition, there is no "missing fraction" P^ in vapors (at moderate pressures) whereas Pp ^20% in most liquids. These data suggest that a radiation "spur model" or its variants should be considered as a likely possibility to explain the liquid phase results.2

*Y. Ito et. al., Can J. Chem. 5Ő, 2395 (198C).2P.W. Pereivel, J. Chem. Phys. 72, 2901 (19S0).

BD21 if* Molecular Ion Formation and Reactivity in Gases. TJ.G. FLEMING, M. SENBA, D.M. GARNER, D.J. ARSENEAU, AND R.J. MIKULA, Dept, of C hemistry and TRIUMF. U. of British Columbia - As a consequence of its slowing down processes, the positive muon thermalizes in either a paramagnetic (as muonium) or diamagnetic environment.The fraction of muonium formed, f^, can easily be identi-

fled from its precession signal, but the diamagnetic fraction, f , is not so easily characterized and may be composed of free muons (unlikely), μ-1" molecular ions or muonium bound in a molecule. Recent studies at TRIUMF in a Neon moderator have revealed the presence of two relax­ations of the diamagnetic signal in the presence of trace amounts of added X e , a fast (X~5ys_ 1 ) and a slow signal (λ~.OSys"*1 ), the fast relaxing signal being due to ther­mal muonium formation from a NeMy+ molecular ion. On the other hand, there is no fast relaxation seen with either added CH^ or NH^ even though both are exothermic for Mu formation. This suggests an ion-molecule cross-section about 5x larger than the classical Langevin limit, which in turn suggests the importance of muon tunneling, the first time that such a process has been at all charac­terized.

BD22 The Missing Fraction of Muon Polarization in Gases. E. TURNER, M. SENBA, D.J. ARSENEAU, D.G. FLEMING AND D.M. GARNER, TRIUMF and Dept. of Chemistry. U. of British Columbia - Observation of muonium and diamag­netic muon signals in numerous gases at a variety of densities indicates that any specific properties of the gas itself have minimal effect on the magnitude of the missing polarization. Instead, the missing fraction scales with valence electron density and disappears in the limit of high pressure. Thus the lost fraction is identified with depolarization of the by its hyper­fine interaction in muonium as it undergoes charge ex­change with the moderator; the time spent in this regime can be related to the valence electron density. In the absence of a correlation function, the polarization can be averaged over the whole time spent as Mu during cyc­lic charge exchange. Total polarizations determined this way are in qualitative agreement with those deter­mined experimentally. More sophisticated calculations reveal the same trends. Results obtained in a variety of molecular gases ( ^ , C H ^ , l^O, MeOH , CgHj^, c - C g H ^ and TMS) will be presented.

BD23 Temperature Dependence of the Spin Exchange Cross Section of Muonium with Q g in ^:he Range 88K to 478K. M. SENBA, D.M. GARNER, D.J. ARSENEAU, AND D.G. FLEMING, Dept, of Chemistry and TRIUMF. U. of B ritish Columbia - Our group at TRIUMF reported earlier a study of the temperature dependence of the spin exchange re­actions of Mu with O 2 and NO in the range 295K to 4 7 8K,1 We have now extended the measurement with O2 to a low

temperature region of 88K to 296K. From 135K to 296K, the bimolecular rate constant kj(T) was found to vary according £0 the relative velocity of the colliding species, T^, which indicates that the spin exchange cross section of MU-O2 is temperature independent in this range. The value of k^CT) at 296K is in excellent agreement with our earlier study.1 However, it was found that below 105K and above 400K, kj(T) tends to have stronger temperature dependences (Tn , with n>l/2). This deviation from T''2 behaviour can be attributed to the velocity (energy) dependence of the spin exchange cross section. Possible Isotope effects in the spin exchange process will be discussed.

^ . J . Mikula, D.M. Garner and D.G. Fleming, J. Chem. Phys. 21, 5362 (1981).

BD24 Meso Molecular Effects in the Hydrogen Isotopes observed by π~ Nuclear Capture.* K.A. ANIOL, D.F.MEASDAY, M.D. HASINOFF, H.W. ROSER, A. BHAGERI, F. ENTEZAMI, C. VIRTUE, Dept, of Physics, U B C , J.STADLBAUER, Dept, of Chemistry, U B C , M. SALOMON, D. HORVATH, TRIUMF, B.C. ROBERTSON, Dept, of Physics, Queens Univ. - It has been known for some time that the

probability for stopped to be captured by protons in a compound depends quite strongly on the chemical state of the hydrogen1. In measurements made with stopped tt~ in an equal mixture of H 2+ D 2 and in pure HD we have seen that the ir- are captured by protons more frequently in the h 2+02 m ^xture than in the molecular form. Let W be the probability for the π- to be captured by the protons in the gas. Then our results show W ( H2+ D 2)/W(HD) = 1.19 i .02 independantly of pressure between 6 atmospheres and 90 atmospheres.

*D. Horvath, Radiochemical Acta, 28, 241(1981).*Supported by NSERC.

BD25 On the Models of Coulomb Capture of Negative Particles. DEZSŐ HORVATH* 4 FARROKH ENTEZAMI, TRIUMF & The University of British Columbia. - Various models of atomic capture of negative mesonic particles are tested against 321 experimental Coulomb-capture ratios measured on binar systems: gas mixtures, alloys and simple compounds. The comparison has shown that the general agreement between theory and experiment is not satisfactory. We tried to improve on the models via introducing adjustable parameters to be estimated by fitting the experimental data. The predictions of the model proposed by Schneuwly, Pokrovsky and Ponomarev (SPP) 1 are closest to the atomic capture ratios for alloys and compounds while the data measured in gas mixtures are better approximated by the empirical formula of Vasilyev et. a l 2.

1H . Schneuwly, V.N. Pokrovsky, L.I. Ponomarev, Nucl.Phys. A312 , 419(1978).2V.A. Vasilyev, V.I. Petrukhin, V.E. Risin, V.M. Suvorov,D. Horvath, Dubna Report JINR-R1-10222, 1976.*0n leave from Central Research Institute for Physics, Budapest, Hungary.

BD26 Ionization of hydrogen a toms by positrons D.A.L. PAUL, Physics Dep t ■, Univ. o f Toronto M5S 1A7, and M. SCHULZ, Hauptstr ■ 128. 6701 M eckenh e i m . West Germany - The ionization of H atoms by positrons has been studied using the plane-Coulomb and Coulomb-Coulomb Born appro­ximations, the fivefold differential cross section

d '.is obtained for incident positrons of 100 eVdL d d _ r

in a number of cases showing that the angular distribu­tion is strongly dependent on the effective charges which are used in the Coulomb-Coulomb approximation. The cross sections integrated over all angles are less sen­sitive to the charges and lead to interesting results when the outgoing positron energy is low. This type of result has a direct bearing on the understanding of energy degradation of positrons which are introduced in­to atomic gases, for example from a radioactive source. The differential cross section do/dE decreases as - x/k

e + at very low values of k+ , where k is the wave number of the outgoing positron and λ is a constant.This latter result contrasts strongly with the thres­hold law for ionization by electrons.

BD27 A Fourier Transform Treatment of the Ouantum Mechanical Two Level System in an Applied Electric Field - Single Field Case.* T. GRINDLAY,

J. MIZIAt, (GWP)Ztt, Waterloo Campus - Fourier transform techniques are used to obtain an approximate expression for the response of a quantum mechanical two level system to a small monochromatic applied electric field. A comparison with the results of a numerical integration of the differential equations shows that the approximation

28

Is equally satisfactory close to and far from resonance. The method is easily extended to two or more applied fields.

*Supported in part by the NSERC of Canada.

ÍPresent address: Physics Department, Queen's University

ttGuelph-Waterloo Program for Graduate Work in Physics

ROOM 129

SURFACE SCIENCE

BEI Oxidation Processes on CdSe and Se Electrodes. W . K SEARS and S.R. 10RRISON, Energy Research Institute, Simon Fraser University - Measurements of hole capture by various aldehydes, organic salts, and alcohols were performed on CdSe and Se-coated CdSe. It was found that CH2O and (CH0)2 ate oxidized by reacting with photopro- duced holes from the valence band of n-type CdSe and then re-injecting electrons into the conduction band (a process known as current doubling). This, however, only occurred in basic solution. It was also found that the photodecomposition of CdSe In neutral solution proceeds as a current doubling reaction. These processes occurred just as readily with the Se layer and It is concluded that photoproduced holes are easily trans­ferred from the CdSe to the Se surface. Possible mechanisms for these reactions will be presented.

BE2 LEED fine structures and surface characteriza­tion*, J.-M. BARIBEALTand J.-tï. CARETTE, Département de physique et Centre de Recherches sur les Atomes et les Molécules (C.R.A.M.), Université Laval, Québec, Canada G1K 7P4. Low energy I-V curves of the specular beam on W(001) and W (110) at several angles of incidence and azimuthal directions have been measured. In these spec­tra sharp intensity fluctuations are observed. They are related to an interference process involving pre­emerging diffracted beams trapped between the substrate and its potential energy barrier. High resolution mea­surements of these LEED fine structures are used to de­termine accurately the shape of the surface potential barrier of these surfaces. These spectral features are also studied on oxygen and hydrogen covered surfaces.It is found that qualitative information on the struc­ture of the adlayer can be obtained by looking at the changes it induces on the fine structures line shape and intensity.

*Supported by NSERC and by les Fonds F.C.A.C.

BE3 Structure and Dynamics of Physisorbed Layers Studied with Atomic Beam Scattering. L. Danielson, l.H.Lins, M.Mengel, G.Scoies* and U.Valbusa**, The Centre for Molecular Beams and Laser Chemistry, Univ. of Waterloo, H.Jonsson and J.Weare, Dept, of Chemistry, Univ. of Cal itorn i a . San Diego. - The full potential of atomic beam scattering from surfaces is only now being realized. Unlike other surface diffraction probes, we show that it is possible to accurately calculate diffraction peak intensities as well as peak positions. We present measurements of H atom scatter­ing from Xe and Kr layers on graphite. This is a useful test case since the atom-surface potential can be constructed under the assumption of pairwise addi­tivity. The diffraction intensities are obtained by performing accurate close-coupling calculations, and compared to experiment after convoiuting for the spread

of beam velocities and the finite dimensions of the beam and the detector. The dynamics are studied through the temperature dependence of the scattering, using the Debye-Waller model.

*Guelph-Waterl00 Program for Graduate Work in Physics **Physics Dept., Univ. of Genova, Genova, ITALY

BE4 Oxveen-Induced Phase Transitions on Pt(100),K. GRIFFITHS, T . E . JACKMAN, J.A. DAVIES, andP.R. NORTON, Atomic Energy of Canada Limited, Chalk River, Ontario - Two new surface phases on Pt(100) Induced by the adsorption of oxygen atoms under various conditions are reported. Using Rutherford backscat- terlng (RBS) and nuclear microanalysis (NMA), we have shown that 0.077x101-5 Pt atoms cm“ 2 are displaced signi­ficantly (by 0.025 nm) from their bulk-like positions at an O 2 coverage of =0.64. This phase transition Is associated with a very complex LEED pattern and unusual adsorption/desorption kinetics. Adsorption of O 2 onto the clean (lxl) surface at 300 K produces a (3x1) LEED pattern which Is associated with the second phase transition. This phase is also characterized by large Pt atom displacements, involving 0.50x10^5 atoms cm“^. Removal of a small portion of the oxygen from the satu­rated surface to 0.4 monolayers also gives rise to a (lxl) LEED pattern but with a high background Intensity (observed at 660 K ) . RBS Indicates that this surface Is the same as that which gives rise to the (3x1) LEED pattern described above. Increasing the temperature further results In a gradual reversion to the hex phase.

BE5 Hysteresis In a C0-Induced Pt(100) Surface Phase Transition. T.E. JACKMAN, K. GRIFFITHS, J.A. DAVIES, and P.R. NORTON, Atomic Energjr_of Canada Limited, Chalk River, Ontario - The clean surface of Pt(100) Is recon­structed to a hexagonal ("hex“ ) phase. Rutherford back- scattering was used to detect the temperature at which the removal of the reconstruction began as the crystal was cooled in a background pressure of CO (I.e. the adsorption process). This transition was completed after lowering the temperature by less than 5 K from the first appearance of the (lxl) phase. In order to ini­tiate the reverse (lxl) hex transition (in the same background pressure of CO), the Pt(100) crystal had to be heated to a much higher temperature than was the case when cooling, thus giving rise to a large hysteresis loop. The absolute coverage of CO during each phase was measured using the nuclear microanalysis technique.These results will be discussed in terms of «1 recently proposed model for the surface phase transition.

ROOM 129

O PTICS AND LASERS

BF1 Visible to Mid-Infrared Electromechanical Modulator^ at 20 kH2. D. VINCENT and G. OTIS, Defence Research Establishment, Valcartler - We have designed,built and tested an achromatic modulator that uses a torsion bar scanner as the active element. The light beam is brought to focus at the scanner by an off-axis parabolic mirror and then recollimated by a second Identical mirror. The angular deviation Introduced by the scanner mirror Is converted to linear translation by the second parabolic mirror. This linear translation across an output aperture (circular or rectangular) yields amplitude modulation. The full- beam width and divergence may be as large as 6 mm and 10 mrad. By proper off-setting of the beam, the modulation frequency can be changed from f to 2f. Modulation depths greater than and harmonic

distortion less than -10 dB have been obtained. With the chrome-gold coatings used, the total transmission of the modulator is 60% at 0.633 pm and 86% at 10.6 pm.

BF2 Optical Resonators with Gaussian Reflectivity Mirrors: Misalignment Sensitivity*7 N. MCCARTHY and P. LÂVlüNt, INRS-Energie, Umversvte du Québec, Varennes - The problem_of~the misaligned optical resonator with a Gaussian reflectivity mirror is analytically solved. It is shown that the fundamental mode remains a Gaussian beam which propagates along a tilted axis in the misa­lignment plane. The exact analytical solution yields simple expressions that characterize the misalignment sensitivity of the resonator. The use of a Gaussian reflectivity mirror in a misaligned optical resonator is shown to be advantageous in many aspects.

* Work supported by the Defense Research Establishment, Val cartier.

BF3 Modèle théorique du comportement d'une mince couche d'huile sous l'effet d'une^ irradiation infra­rouge*. FERNAND LEDOYEN, M. CORMIER, LLCMR, Département de physique, Collège militaire royal de Saint-Jean - Des couches d'huile ont été utilisées1 pour réaliser l ’holographie en infrarouge. Nous avons mené une étude théorique pour déterminer les phénomènes physiques qui interviennent lors de l ’enregistrement de l ’hologramme. Nous avons entrepris ce projet de façon à isoler les facteurs physiques importants et ainsi, à pouvoir amé­liorer les caractéristiques du milieu enregistreur, v.g. la sensibilité, les temps de réponse et de relaxa­tion. Le modèle définitif, interprète les résultats expérimentaux^ de façon semi-quantitative, i .e q u ’il nécessite l ’ajustement de certains paramètres dont les valeurs sont encore inconnues.

M. Cormier, M. Blanchard, M. Rioux et R. Beaulieu,Applied Optics, 17, 3622 (1978).

*Subvention CRDev 3610-371

«BF4 Optical Tunnelling or Else? S.L. CHIN, GY.

FARKAS+ P. GALARNEAU and F. YERGEAU. LROL, U. Laval - It is normally expected that the probability of multipho­ton ionization of atoms and multiphoton electron emis­sion from a metal surface by a not too intense CO2 laser (hv = O.II7 eV) is too small to be observable. Yet we have recently observed both ionization of Xe, Kr atoms and electron emission from a gold surface using a 4 ns CO2 laser pulse at ~ 1 012W/cm2 and ~ 109W/cm2 respecti­vely. Theory of optical tunnelling [1] requires an in­tensity a few orders of magnitude higher in both cases. Puzzle? Yes, indeed! We attempt to give a reasonable interpretation.

[l] Keldysh, L.V. , Sov. Phys. JETP, 2_0, 1307 ( 1965) -

* Supported b y NSERC and le Fonds FCAC of Quebec.

+ On leave (1982-1983) from the Central ResearchInstitute for Physics, Hungarian Academy of Sciences.

BF5 Single Pulse Detection of Self-focusing of a CO2 Laser Pulse in SF6 using Bistability.π P. GALARNEAU, S.L. CHIN, MA XING-XIAOt GY 7 FARKAS and F. YERGEAU.LROL, U. Laval - We experimentally show that self- focusing of a CO2 laser pulse in a polyatomic gas (using SF6 as an example) during multiple photon interaction can be detected by observing the single pulse bistabi­lity character. The validity of this method is discussed.

* Supported by NSERC and le Fonds FCAC of Quebec.

+ On leave (1982-1983) from the University of Science and Technology of China, Chinese Academy of Sciences.

BF6 Losses of phase conjugate resonators. M. PICHE, P.A. BELANGER and C. PARE, LROL, U. LAVAL - The direc­tional behaviour of power losses in aberrated multi­aperture optical resonators with one or two phase con­jugate mirrors is investigated through integral equa­tions and the reciprocity theorem. In a resonator with one phase conjugate mirror, the losses of a mode travelling from the conventional mirror to the phase conjugate mirror are shown to be larger than the losses of the counterpropagating mode. In a resonator with two phase conjugate mirrors, the losses along each direction are found equal. Experimental implications of those theoretical results will be discussed.

ROOM 129

AERO NO M Y & SPACE PH YSIC S

BG1Arctic Haze. R.M. Hoff and L.A. Barrie, Atmospheric Environment Service - Since the 1960‘s, a noticeable increase has been observed in haze in the Arctic during winter and spring months. The phenomenon is now be­lieved to be due to the importation of man-made sulphate and carbonaceous aerosols to the Arctic from mid-lati­tudinal sources. As part of an international project between the US, Canada, Denmark, Norway and England, three stations to monitor the haze have been in oper­ation in the Canadian Arctic since 1979. Results from that network show a 40 fold increase in sulphate in winter over summer at these Arctic sites. Light scat­tering measurements of the haze are consistent with the interpretation that sulphate aerosol reduces visibility and some possible sources for the aerosol are examined.

BG2 TemDoral Variations in the Night-Time Hydroxyl Vibrational Population D istribution. D .N.TURNBULL,U. of Western Ontario - Relative populations of the vibrational levels v=2 to v=9 of the hydroxyl radical have been determined from observations of the Δν=2,3 and 4 sequences of the vibration-rotation bands in the night airglow using a Fourier transform spectrometer. The results indicate that the population distribution is not constant: population of the upper levels lower by a factor of two than that found in other studies has been observed. An attempt is made to explain the variability in terms of the height of the emitting layer.

30

BG3 Twilight Lithium Enhancements at Victori a . B ■C. following Rocket Releases of Lithium Vapour at Poker Flats. Alaska.* H.M. SULLIVAN, University of Victoria.

Strong twilight Lithium emissions were observed at Victoria, B.C. following two rocket releases of Lithium vapour in the height range 310 km down to 90 km, and one point release at 1200 km, at the Poker Flats Range near Fairbanks Alaska. The first two releases, which took place during early morning twilight on April 15 and April 16, 1982 were followed by emission intensities of approximately 375 rayleighs after 3 days; the point release, which took place during the morning twilight of April 20, 1982, was followed by a similar enhancement after 11 days.

*Supported by N.S.E.R.C. and University of Victoria.

ROOM 139

A ST R O N O M Y AND A STRO PH YSIC S

BH1 Radio Patrol of the Northern Milky Way, A.R. TAYLOR* and P.C. GREGORY, UBC - We have carried out a survey of the galactic plane for variable sources at λ=6 cm. An area of over 500 square degrees was searched, with 3* resolution, for variations on time scales of a few days (short-term) and one year (long-term). Twenty- three new variable sources have been discovered in the first 40% of the data, and 18 sources are probably variable. About 50% of the variables exhibit short-term variations. Evidence suggests that these sources are primarily galactic, with Lr in the range 10d -10J erg/ sec; similar to known X-ray binary systems such as Cyg X-3, SS 433 and Sco X - l . Extensive follow-up observa­tions have been carried out for only one variable (GT0236+610). This source is periodic, undergoing a radio outburst every 26.52 days, and is identified with a B0 star which is also an X-ray and probable γ -ray source. The long-term variables are probably extraga­lactic. The survey data also provide the most sensitive catalogue to date of discrete radio sources in the galactic plane; complete to '70 mjy and including sources as weak as 20 mjy. Sixteen stars, of predominantly B spectral type, are co-incident with catalogue sources.

*present address, U. of Toronto

BH2 Precessine Jet Model For the Supernova Remnant G109.1-1.0, P.C. GREGORY and G .G . FAHLMAN, UBC - We propose that the central X-ray pulsar in G109.1-1.0, designated IE 2259+586, ejects two oppositely directed precessing jets or beams, which give rise to the observed radio structure. The radio emission is interpreted as synchrotron emission from electrons accelerated at the interface of the jets with the walls of the SNR. Thus the observed intersecting arcs of radio emission represent the trace of the precessing jets on the supernova remnant walls. The precession axis is inclined at 37 degrees to the line of sight and the precession cone half angle is 55 degrees. The observed large scale X-ray jet in G109.1-1.0 is found to coincide in position with the precession axis as was found for the X-ray jets from SS 433.

BH3 GL 618 - The M issing Link B etween Red Giants and Planetary Nebulae? SUN KWOK, H.I.A. Ottawa - GL 618 is an infrared object discovered in the US Air Force Sky Survey and has been found to possess the properties of red giant envelopes and young planetary nebulae. High angular resolution (0V07) radio observations by us have uncovered a compact ionized region of size OV4xO'.'l embedded in the infrared source. The bipolar morphology of GL 618 is suggested to be

the result of an anisotropic density distribution in the circumstellar envelope of its red giant progenitor. The central star of GL 618 is estimated to have a mass of 0.8 M@ and is now rapidly evolving to the planetary nebula stage.

BH4 A Search for a Ma2n etic Field Associa ted With a Large X-Ray Rine. N.W. BROTEN, J.M. MACLEOD, and J. P. VALLÉE, Herzberg Institute of Astrophys ics, National Research Council of Canada, Ottawa, Canada. - Spurred by a report of the detection of a possible giant X-ray -emitting ring in Gemini-Monoceros, we have searched for evidence of the presence of an enhanced magnetic field which might be associated with this ring. We have made observations of the linear polarization of background radio sources at a wavelength of 2.8 cm with the 46-m telescope of the Algonquin Radio Obser- vatoryi1), and 20 cm, 18 cm, and 6 cm with the NRA0 Very Large Array in New Mexico(*·) . From this data, rotation measures have been computed for sources shining through the ring, to compare with these sources along lines of sight adjacent to the ring.

(*) The Algonquin Radio Observatory of the Herzberg Institute of Astrophysics is operated by the National Research Council of Canada as a national facility.(a ) The U.S. National Radio Astronomy Observatory is operated by Associated Universities, Inc., under contract with the U.S. National Science Foundation.

BH 5 Observa t i on s Spectrales et Modelage Physique de l ^ b jet Sharpless no. 121. J.P. VALLÉE, Section d ’a stronomie. Institut Herzberg d 'astrophysique, Con­seil national de recherches du Canada, Ottawa, Ont. - La nature exacte de l'objet no. 121 dans le catalogue de Sharpless(1959) a donné lieu à une controverse v i ­ve, puisque quatre interprétations ont été offertes à partir des observations passées (1. région HII ioni­sée; 2. nébuleuse planétaire; 3. restes de supernova; 4. objet proche superposé sur une radiosource extra­galactique). De nouvelles observations de cet objet ont été faites à l'Observatoire Algonquin de radioas­tronomie au Lac Traverse, Ont.(·) aux longueurs d'on­de de X 2,8 cm et de 9,0 cm, et des raies d'émission ont été aperçues. Leur analyse a permis un choix en­tre ces quatre interprétations, ainsi que le modelage physique pour en obtenir les paramètres physiques de base (densité, température, etc) et dynamiques (âge, puissance, etc). Des observations aux ondes optiques seront nécessaires pour parfaire notre étude.

(') L'Observatoire Algonquin de radioastronomie, de l'Institut Herzberg d'astrophysique, est opéré par le Conseil national de recherches du Canada.

BH6 CO D istribution Along the Southern Galactic Plane. W.H. McCUTCHEON, Univ. of B . C ., B.J ROBINSON,R.N. MANCHESTER, and J.B. WHITEOAK, C.S.I.R.O. — The Southern galactic plane, in the ranges 294e <_ Í, < 358°, ~0?075 b <_ 0?075, has been surveyed in the J = 1-0 line of ^2C0 with a sampling interval of 3' arc. The variation of radial velocity with longLtude shows well defined terminal velocities whose locus matches fairly well rotation curves determined from HI and CO observations along the northern galactic plane. Over certain ranges of longitude, absence of CO emission near the tangential velocity is more apparent in the southern observations and strongly suggests that there are arm-like structures in the CO distribution. In particular, the southern portion of the HI 3.5 kpc expanding arm has a clearly defined CO counterpart.The radial distribution of CO from the galactic centre displays two pronounced peaks - a sharp peak near R = 3.5 kpc and a broader peak centred near R = 7 kpc.

Northern CO data shows only a broad peak, centred near R = 6 kpc. Using a standard model of the Galaxy, we identify much of the CO emission with sections of spiral arms.

BH7 Limits to Interstellar SiN

P.A. FELDMAN, H.E. MATTHEWS, M.B. BELL, and G.HERZBERG, H.I.A., OTTAWA, and S. SAITO, Y. ENDO, andE. HIROTA, Inst. Mol. Science. Okazaki. Japan - Observations have been made with the Haystack 37-m radio telescope of the N=1*0, J-l/2+1/2, F-3/2+3/2 and N=l+0, J=3/2+l/2, F-5/2+3/2 transitions of silicon nitride in Orion KL, Sgr B2, IRC+10o216, TMC-1 (HC5N and NH3 peak positions) and in several SiO maser stars. Limits to the abundance of interstellar (and circum- stellar) SiN are derived and compared with theoretical predictions.

BH8 On the Excitation of Water in Ori Mil:* E. N. RODRIGUEZ KUIPER.t Bennett Medical Corp., T. B. H. KUIPER, JPL, Caltech - Statistical equilibrium calcula­tions including photon-trapping have been carried out using the large velocity gradient formalism to model the excitation of water vapour for the range of densities, temperatures, column densities and infrared fluxes which are believed to occur in the vicinity of the Kleinmann- Low Nebula in Orion. These model calculations are used to identify the possible causes for the increase in emission observed in the 183 GHz transition between 1977 and 1980 (see Kuiper et al., this meeting), and to predict intensities for other transitions of water which may be searched for in future airborne and space observations.

* The research described in this paper was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration, t JPL Research Affiliate

BH9 Equilibrium Models of Neutral Atomic Zones around H1I Regions P .E. DEWUNEY and R.5. ROGER, Dominion Radio Altrophysical Observatory, HIA/NRC, Penticton, B.C. - We present equilibrium models of conditions in photodissociation regions beyond the ionization boundaries of HII regions excited by 05-B3 type stars embedded in medium density (10-3000 cm-3) molecular clouds. The atomic zone (region of dissociated hydrogen) is coexistent with the region of ionized carbon since the two processes are controlled by the same UV spectral range (91.2 - 110. pm). The models include, as a function of radius, a simultaneous solution of H-Hz dissociation balance, ionization balance of carbon, hydrogen and sulfur, and thermal balance of several heating and cooling processes. In the atomic zone the dominant heating process, photo­ejection of electrons from dust grains, is balanced by the dominant cooling process, 157 pm 1ine-radiation cooling from col 1isionally excited C+ , yielding temperatures in the range 20K to 200K. Other thermal processes tend to dominate near the dissociation boundary. Observable properties such as total mass, cloud size, column densities of HI and C+, and HI line profiles are calculated.

BHlO Radio Observations of the Gamma-Cygni Nebula, L.A. HIGGS, I.L. LANDECKER, Dominion Radio Astrophysical Observatory, Penticton, B.C. - Observations of the strong radio filaments in the eastern portion of the supernova remnant G78.2+2.1, made at the VLA at wavelengths of 21 and 6 cm, have been combined with lower resolution observations made at Bonn and DRA0.This has enabled the radio structure and spectral index of the Y-Cygni Nebula, an HII region in the midst of the non-thermal SNR filaments, to be mapped. The nature of this unusual HII region will be discussed in relation to these radio observations.

BH11 A Survey of the Cygnus-X Region in the Hlhfea Recombination Line

T.L. LANDECKERDominion Radio Astrophysical Observatory, Penticton - The Cygnus-X region has been surveyed with the URA0 26 m telescope in the H166a recombination line at 1424 ftiz. Angular resolution was 36 arcmin. 123 spectra were obtained on a grid of about one beamwidth. This survey detected emission from the diffuse ionized gas rather than the dense cores of the HII regions studied in other surveys. Comparisons have been made with HI, CO and OH observations. A separation of thermal and non-thermal emission has been effected and electron temperatures derived. The Cygnus-X region is compared with HII regions in other parts of the Galaxy.

BH12

H o l o g r a p h i c S t u d i e s o f t h e P e n t i c t o n

R a d i o T e l e s c o p e s

C. H. C o s t a i n a n d J. A. G a l t

D o m i n i o n R a d i o A s t r o p h y s i c a l O b s e r v a t o r y

I n t e r f e r o m e t r i c t e c h n i q u e s h a v e b e e n

u s e d to m e a s u r e t h e c o m p l e x d i f f r a c t i o n

p a t t e r n s o f t h e a n t e n n a s a t t h e D . R . A . O .

T h e s e m e a s u r e s n o t o n l y p e r m i t p r e c i s e

d e t e r m i n a t i o n s o f t h e r e f l e c t o r s u r f a c e s

b u t a l s o m a y b e u s e d to e x a m i n e t h e p o s i t i o n

a n d t h e p e r f o r m a n c e o f t h e f e e d h o r n s .

R e c e n t s t u d i e s o f t h e 2 5 m a n t e n n a

a n d t h e s y n t h e s i s t e l e s c o p e s a r e d i s c u s s e d .

BH13 A Digital Cross-Correlation Receiver for a Synthesis Radio Telescope

W.F. L0, D. ROUTLEDGE, J.F. VANELDIKElectrical Engineering Dept., Univ. of Alberta, Edmonton

P.E. DEWDNEY and T.L. LANDECKERDominion Radio Astrophysical Observatory, Penticton - A real-time digital signal processor for a synthesis radio telescope is described. The processor accepts video signals of bandwidth 4 MHz, quantizes them to 3 levels, and performs delay equalization, phase rotation, and cross-correlation. The quadrature output is produced very simply in software using a band-limited form of the Hilbert transform. The processor produces four complex interferometer outputs simultaneously, and is capable of producing ten. It is based on a 16-bit microprocessor (Motorola 68000). Maps of the extra­galactic source 3C66 have been made with the new processor, and, for comparison, with a conventional processor. The new processor will be used as the cross­correlator for the 408 MHz continuum channel being added to the DRA0 Synthesis Telescope.

32

BH1Í4 Constraints on the Generalization of Lorentz Transformations to Superluminal Speeds.* L. MARCHILDON and A.F. ANTIPPA, U. du Quebec a Trois-Rivières, and A.E. EVERETT, Tufts U . - In the past fifteen years, several proposals were made to generalize the Lorentz transformations so as to include inertial frames moving faster than the speed of light in vacuum. The equi­valence of these superluminal inertial frames to the ones of ordinary special relativity was then postulated, and is known as the Extended Principle of Relativity.We argue that the set of all coordinate transformations between equivalent frames must form a group. We then investigate the smallest possible groups that include the proper orthochronous Lorentz group together with at least one superluminal transformation. This we do in the two cases of real and complex superluminal trans­formations. Realizing that the minimal groups so ob­tained necessarily include transformations which are clearly not symmetries of known physical laws, we con­clude that the Extended Principle of Relativity is experimentally untenable.

*Supported in part by NSERC.

BH15 The Youne Open C l u ster S tock 16, An Example of Star Formation in an_E_lephant Trunk?, D.G. TURNER, Laurentian University — Stock 16 is a small, 2-pc diameter, sparsely-populated, young open cluster located on the edge of an extensive dust complex in Centaurus, at a distance of 2 kpc. Cluster stars exhibit a complete lack of differential reddening, although they lie very close to surrounding filaments in the dust complex, and there is a peculiar, extended, distribution of faint cluster stars relative to the spherically-distributed bright members. Both features suggest that Stock 16 formed as a consequence of the pinching off and subsequent contraction of the head of a former, elongated, elephant trunk structure which protruded into the edge of the emission nebula RCW 75. The distribution of faint cluster stars is consistent with their origin in smaller dust globules lying near the edge of this expanding H II region. Stock 16 may therefore be an excellent example of low mass star formation from small Bok globules, and of star cluster formation from an elephant trunk structure.

BH16 The Open Clusters NGC 2287 and NGC 2353 M. PIM F i t z g e r a l d and u .l .h .Ha r r i s u . Waterloo and d a u - m k

classification has been determined for over A6 stars in NGC 228/ to the main sequence turn off; a similar but less complete sample has been classified in NGC 2353.In NGC 22ö7 the HR diagram is well defined with a turn­off at B9; it has two Ap stars, a t least one composite, and six bright giant members. In NGC 2353 we have new photoelectric UBV photometry, which shows two distinct sequences strongly suggestive of a substantial binary star population Ap stars are also present in this cluster.

BHl? NGC 5l28-The Globular Cluster System J.E.HESSER DAO,H.C.HARRIS DAO,S,VAN DEN BERGH DAO,G.L.H.HARRIS U N IV.WATERLOO - Spectroscopic, photometric, and star count information for globular cluster candidates near the peculiar galaxy NGC 5128 (Centaurus A) reveal a system of ^ 6 0 0 globular clusters and suggest a dis­tance to the system of ^ 3 M p c . Radial velo­city data for 19 clusters based on VIDICON spectra obtained with the CTIO 4-m telescope allow us to determine a galaxy mass of ^ l . ó x l O 1 (D/5)^?0, and an implied ^ / L v =16 (5/D). The brightest clusters appear to be comparable in size and luminosity to OJCen and the clusters as a whole are redder and probably more metal rich than those in the Galaxy.

BH18 Globular Cluster Systems in Two Field Galaxies. W.E.Harris, McMaster U . , and D.A.Hanes, AAT. - We have detected globular cluster systems around two early-type galaxies, NGC 524 (SO, vr - 2600 km s_i) and NGC 1052 (E2, v = 1400 km s x) , by star counts from lllaJ prime focus plates taken at the CFHT. For NGC 1052 (the only elliptical in the small group HG44) we find (240 *"40) globular clusters to Bj(lim)-tf 24.2. For the especially interesting NGC 524 (a large, face-on, "ringed" SO which is the dominant central member of a compact group), we find (500 i 50) clusters to Bj(lim) * 24.7. In both of these systems we estimate the specific frequency (i.e., number of clusters per unit (Mv®-15) galaxy luminosity) to be S ~ 4, typical of ellipticals in small groups and in the field. Their radial distributions are also discussed.

BHl9 Spectroscopy of Subgiants in NGC 5139 (OJCentauri) J.E.HESSER DAO, R.A.BELL NSF,G.L.H.HARRIS UNIV.WATERLOO, and R.D.CANNON ROE - A complete sample of faint stars in a small area near Ca n n o n ’s photoelectric sequence has now been surveyed. Of the 30 stars most re­cently observed, 14 have velocities inconsis­tent with cluster membership. Thus,a-: the innermost radius where crowding permits the main sequence to be studied, only half of the stars are m embers’ A range in CFe /H3 from a-. -0.5 to -1.5 is seep among the members, with the majority having f F e / H ^ ^ - l · 5. We suspect for the first time that not only is there a geniune temperature range among e volved WC e n stars (as previously found by us and others), but that there may also be a range of metal- licities among subgiants at a given tempera­ture .

BH20 CCD Photometry of NGC2257 in the Large Magellanic Cloud R.D. MCCLURE and J.E. HESSER DAO- The CTIO prime-focus CCD camera has been used on the 4-m telescope to obtain deep B and V exposures. Nine hundred stars have been measured with the profile fitting program RICHFLD at Kitt Peak. The colour-magnitude dia­gram extends to VÎ.24 and clearly reveals the main-sequence turnoff of this very old cluster. Cluster properties inferred from the new data will be presented and discussed.

BH21 A Two-channel A stronomical Photometer; MATTHEWS, J.M., WEHLAU, W.H., & SYMONDS, G. r 7; Dept, of Astronomy, U.W.O. - Sky conditions in southern Ontario are rarely suitable for precise rapid photo­metry using conventional single-channel techniques. To carry out such observations at the University of Western Ontario observatory, a two-channel differ­ential photometer has been built for use with the 1.2 m telescope. Its design offers several advan­tages, including large programme/comparison star separations {up to 45 arc minutes), mechanical sim­plicity, and efficient operation. Preliminary tests of the instrument indicate that photometry cf accu­racy better than 0™01 is attainable even on hazy nights.

BH22 Duration of Totality in U Cephei.C.D. SCARFE AND P.A. DELANEY*7 Climenhaga Ohs'., U. of Victoria - UBV observations of primary minima of the eclipsing system U Cep have been obtained from 1969 to 1981. The duration of totality has been estimated by fitting straight lines to short sections of the light curve before, during, and after totality. The duration

is usually shorter in B light than in V, and always shorter still in U light. For the strongly distorted eclipses of 1974 and 1975 the correlation between the duration of totality and the delay of mid eclipse found previously1 is confirmed. Moreover for these eclipses the slope of the ingress portion is steeper than that for egress, although no such systematic behaviour is apparent for undisturbed eclipses. These phenomena are related to the geometry of U Cephei's primary eclipses and to the distribution of circumstellar material in the svstem.

Crawford, R.C., and Olson, E.C., Pub. Astr. Soc.Pacific 91, 413 (1979)*Present Address: Whiteshell Nuclear Research Estab­

lishment, Pinawa, MB, ROE 1L0

BH23 The UBVRI Light-curve o f FK Comae Berenic e s , STEVEN MORRIS, U. of C. - The rapidly rotating variable star FK Com was observed at Kitt Peak during February, 1981. The resulting UBVRI light-curves have been analysed in conjunction with previously-published light-curves to obtain an improved period of 2.3996 days. The secular changes in the light-curves are discussed in terms of the starspot and the bright accretion spot models which have been proposed for this star.

BH24 JHK Observations of Classical Cepheids and an Improved Calibration of the Infrared Period-Luminosity Relations. D.L. WELCH, F. VíIELAND, C.W. McALARY, R. McGONEGAL, B.F. MADORE, R.A. McLAREN, and Π . Nuegebauer, D . D . 0 ., U. Toronto, C.I.T. - New TDK photometry is presented for sixty-eight galactic classical Cepheids. Full phase coverage observations of twenty-three Cepheids are used to determine IR to optical amplitude ratios. A procedure for recovering mean JHK magnitudes from single-phase observations is described. New JHK period-luminosity relations are reported.

BH25 Photometric Variability of B and A Type Super­Giants . JOHN R. PERCY and DOUGLAS L. WELCH, D . D.O.,U. Toronto - Photometric observations of the following early-type (09-A3) supergiants have been obtained at Kitt Peak National Observatory and/or the University of Toronto: HR 130 (κ Cas), HR 627 (5 Per), HR 641, HR 685 (9 Per), HR 1040, HR 7551, HR 7573, H R 7678, HR 7699,HR 7763 (P C yg), HR 7977 (55 C yg), HR 8279 (9 Cep),HR 8334 (v Cep), HR 8371 (13 Cep), H R 8428 (19 Cep), and HR 8561 (26 Cep). All but HR 7573 and HR 7699 are variable, with a range of about 0*?05. The light curves are irregular, but characteristic time scales or "quasi periods" can be identified. These range from 2-10 times the fundamental radial period in the earliest- type supergiants, to 0 .2-2 times the fundamental radial period in the later-type supergiants. Based on the time scales, the apparent lack of temperature variations, and the proximity to the β Cep and 53 Per stars in the H-R diagram, the variability is most likely due to non-radial pulsation.

Supported by the N.S.E.R.C. of Canada.

BH26 Optical , Microwave and UV Imagery of a Solar Flare. V. GAIZAUSKAS, Herzberg Institute o f Astrophysics, N RCC; M. rT KUNDU and E.J. SCHMAHL, U ^ of Maryland; R.A. SHINE and B.E. WOODGATE, NASA-Goddard SFC. We compare coordinated multi-wavelength observations of a single solar active region which produced a flare of medium strength on 25 June 1980. The build-up phase is well observed in the low corona with the VLA at 6 cm (resolution - 2"), in the transi­tion zone with the UV Spectrometer-Polarimeter on the Solar Maximum Mission satellite operating at the C IV

A1548 line, and in the chromosphere with the Ha-scanning photoheliograph of the Ottawa River Solar Observatory. The filament overlying the magnetic inversion line at the site of the flare is subject to repeated upheavals in the half-hour prior to the sudden onset of hard X-ray emission; it disrupts and ejects material several min before the impulsive phase. Preflare magnetic changes evident in the circular polarization (V) maps at 6 cm are co-spatial and contemporaneous with rising and twisting filamentary strands. No direct evidence has yet been found for permanent or transient changes in photospheric magnetic structures which could have destabilized the filament. Alternative mechanisms are discussed.

ROOM 128

INDUSTRIAL AND APPLIED P H YSIC S

BJ1 A Superconducting Motor for Marine Propulsion.* D.C. BAIRD, J.G. DAUNT, W.E. EDER, H.D. WIEDERICK and L.S. WRIGHT - Royal Military College of Canada,Kingston. Ontario. The high magnetic flux obtainable using superconducting solenoids makes it possible to design electric motors and generators with higher ratios of power:size and power:weight than is possible using traditional methods. We shall describe the design and construction of a superconducting motor which will serve as a scaleable model of a motor suitable for ship propulsion. The motor is of homo­polar type with a double disc of 0.2 m diameter. The motor will operate using a magnetic field of 5 T, an armature current up to 5000 A, speeds up to 2000 rpm and a peak power of 50 kW.

*Supported in part by DND FE320F165.

Canadian Maglev Levitation Magnet Design.A.A. FIFE, CTF Systems Inc. - An industrial program to develop superconducting magnets suitable for high speed Maglev application has been initiated by the Transportation Development Centre of Transport Canada. The first phase involves a design analysis for a superconducting levitation magnet with racetrack coil form and strength 400,000 Ampere turns, operating isothermally at 4.2 K. Various features of the magnet design will be discussed including coil analysis, stress level estimates, coil quench modelling and dewar design.

BJ 3 Detection of Subsurface Defects in A1-PlasmaCoated Samples. S. AITHAL, G. ROUSSET and L. BERTRAND, Ecole Polytechnique de Montreal - In the study of Subsur­face defects in Aluminium plasma coated Aluminium subs­trates, the influence on the photoacoustic signals due to the surface irregularities in the coating has to be first better understood. Such signals are calibrated by various samples with regular surface defects. The beha­vior of amplitude signals indicate the difference in thermal diffusion into the gas layer in contact with the surface defect, and that of the phase signals indicate the difference^in the thermal wave reflection from the surface defect . The comparison between these above re­sults and those obtained with blackened samples (A1-plas­ma coated and with regular surface defects) shows that the effect due to the inherent light scattering by sur­face is negligible on the nature of the photoacoustic signal. In addition, the photoacoustic cell was designed to minimize the background signal from the scattering

34

absorption on the walls and on the window. With these informations in hand we carry out the analysis of Al- plasma coated sample with subsurface defects.

^R.L. Thomas et al, J. Appl. Phys. 51, 1152, (1980).

BJ4 E ffective Emisslvlty of a Diffuse Cylindro-Inner- Cone. R.E. BEDFORD and C.K. MA, NRC - A blackbody radiator in the form of a lidded cylinder with a re­entrant conical base is important in metrology for its very high effective e m i s s i v i t y (ea ). It is used, for example, in m e a s u r e m e n t s1 of the S t e f a n - B o l t z m a n n constant requiring an accuracy in e_ to 1 in 10^. This shape presents computational difficulties because the entire internal surface of the cavity is not visible from all points on the surface. Previous calculations^” of efl have been only approximate (in the form of a truncated series). We present an exact integral equation solution for e& (x) at all p o i n t s x on the cavity wall using methods we developed earlier1*. We integrate the angle factors analytically for the first time, thereby avoiding inaccuracy associated with numerical integration; derive exact values for ea (x) at singular points; and allow for arbitrary distributions of temperature over the cavity.

^Quinn, T.J. and Martin, J.E., Metrologia (in press).^Chu, Z·, Chen, S. and Chen, H . , J. Opt. Soc- Am. 70,1270 (1980).3Berry, K.H., J. Phys. E: Sci. Instrum. 14. 629 (1981). ^Bedford, R.E. and Ma, C.K., J. Opt. Soc. Am. 64, 339 (1974); 65, 565 (1975); 66, 724 (1976).

Development of a Commercial Neutron Activation Analysis Facility at the TRIUMF Cyclotron . H.P. BLOK, Novatrack Analysis Ltd. - At the TRIUMF cyclotron, the interaction of a high intensity beam of 500 MeV protons with a lead target suspended in water produces a moderate neutron flux via spallation reactions. Approximately 50% of these neutrons are moderated to thermal energies thus permitting conventional neutron activation analysis. The Novatrack facility contains three Ge (Li) or Ge detectors and associated multichannel analyzer together with a PDP 11/34 computer for high resolution gamma spectroscopy. Neutron counting equipment is used to measure natural radioactivity in environmental samples. Samples for analysis are primarily of geological origin although a wide variety of sample materials has been analyzed. Elements in highest demand at present include Au, U, W, Ta, As, Sb and the rare earth elements.

ROOM 128

INSTRUMENTATION AND EXPERIMENTAL TECHNIQUES

Polarized 3He Ion Source Based on the 23S i Metas­table State,1 R.J. SL0B0DRIAM, R. LABRIE, R. LAPOINTE,L. POULIOT, J. GIROUX and Y. GAGNON, Université Laval - Laboratoire de Physique Nucléaire - Quebec G1K 7P4 - Ca­nada. - This 3He polarized ion source based on a new i­dea is in development since 1930. We report on the successful production of an intense thermal beam of me­tastables, 6^101 p,sec“ 1sr“ 1, of energies between 0.07 and 0.1 eV - as measured, by using a cold cathode dis­charge enhanced by an axial magnetic field, and the se­paration and focussing of the (F=j m-p=3 ) and (F=3/2 mp=3/2) components with a lh cm variable gap sextupole The atomic beam thus prepared is 95$ polarized in atomic spin, as we have measured deflecting it with an inhomo­geneous dipole field. The final design parameters of the source are now frozen for operation inside the HV

terminal of a CN Van de Graaff but it is of universal use in (+) ion accelerators. Using an adiabatic RF transition the nuclear polarization is enhanced theore­tically to 100$. The intensity should exceed 100 parti­cle - na2.’SJ, S lob odri an, Nucl. Instr. and Meth., 185 (19Ô1)584, & Refs, therein.

2This is about a factor of 50 over the Birmingham Lamb Shift Scheme1).

BK2 Bean Cavity Interaction Study with a High Intensity Pulsed electron GunU ‘ ITTC.D. CHAN, J. McKEO.N and P . .(Γ S1RÖ, IECL, Chalk River Nuclear Laboratories, Chalk River, Ontario, Canada - Excitation of higher order modes by beam bunches with high charge density is a cause of beam energy loss and beam breakup in accelerators. Although significant advances have been made in computer codes for calculating quanti­tatively the interaction between beam and accelerator cavities, experiments are necessary to determine the levels of beam excitation of higher order modes. These experiments require electron sources with high peak current if the behaviour of charged bunches in an electron storage ring is to be simulated. The recently completed pulsed electron gun at Chalk River Nuclear Laboratories produces 5 ns pulses with 10 U electrons per pulse at a duty cycle of 5 kHz. The con­struction and coumissioning of this gun, calculations on the injection of the pulsed beam into the Electron Test Accelerator and beam cavity interaction experi­ments will be described.

BK3 IsoT race P rogress R epo rt. * W. E. KIESER andthe ISOTRACE GROUP, D ep t. o f Physics and D ep t. of

G eology, U n iv . o f To ron to - Assembly and acceptance te s t in g o f th e Tandetron A c c e le ra to r U l t r a s e n s it iv e Mass S pectrom eter are a lm ost com plete and work has begun on th e de m onstra tion o f i t s v a r io u s c a ja a b i l i t ie s in f u l f i l lm e n t o f the developm ent c o n tra c t w i 'h Energy, Mines and Resources and Environment Canada. R esults o f the acceptance te s ts which are la rg e ly based on carbon is o to p e r a t io measurements and r e s u lts o f thedevelopm ent c o n tra c t te s ts w hich in c lu d e work on a wide range o f atoms w i l l be p resen ted . P rogress on the a l l - e l e c t r i c io n source l i n e , th e io n m icropcobe, the n e g a tive ha logen s p u tte r sou rce , the t im e - o f - f l ig h t l in e fo r heavy e lem ent id e n t i f i c a t io n and the on l in e data a c q u is i t io n and c o n t ro l system w i l l a ls o be documented.

* Supported by th e N a tu ra l Sciences and E ng ineering Research C o u n c il and the P rov ince o f O n ta rio (B ILD ).

BK4 X-ray Absorption Studies at S SRL.* E.D. CROZIER, N. ALBERDING and A.J. SEARY, Physics Dept., Simon Fraser U. and R. INGALLS, Physics Dept., U. of Washington - Synchrotron radiation is now available at the Canadian wiggler side station which has been constructed at the Stanford Synchrotron Radiation Laboratory. The first part of this paper will describe briefly the experi­mental facility which uses a double crystal monochroma­tor to provide an intense, collimated, polarized mono­chromatic x-ray beam in the energy range 3kev to 35kev. Our present experiments with this facility involve EXAFS and XANES (X-ray Absorption Near Edge Structure) studies of ordered or disordered systems as a function of temperature and/or pressure. As an example, the second part of this paper will present the results of a pressure-dependent study of bond lengths and Sm valence states in SmS, a mixed valence compound which undergoes an insulator-to-raetal transition under pressure.*

Supported by grants received from NSERC of Canada, and the NSF and NIH in cooperation with the Department of Energy, U.S.A.

BK5 Dispersion - M a tching with a Six-Quadrupole Twister" D .A .HUTCHEON, C . A . MILLER & G . M . STINSON, TRIUMF & Unlv. of Alberta. - A six quadrupole beam twister Is being Installed on beam line 4B at TRIUMF.The system, which rotates beam dispersion from the horizontal into the vertical plane, will be used to dispersion-match the primary proton beam line and the medium resolution proton spectrometer (MRS), ultimately yielding better energy resolution for spectrometer experiments. This unique six-quadrupole twister has a unit transfer matrix between image and object locations and is also physically rotatable to compensate for phase space rotation caused by a solenoid. Details of design and performance will be given.

BK6 Transport of Radio-Isotopes Via a Long A ir Chute. J.J. BURGERJON, Z. GELBART, J. LENZ & H.P. SPRENGER TRIUMF. - “Air Chutes" also known as “pneumatic transfer systems" or "rabbits" are frequently used for fast, remotely controlled, transportation of radio-isotopes.At TRIUMF such systems are used in three locations: at the Thermal Neutron Facility to expose samples for neutron activation analysis, between the 42 MeV Cyclotron and the Radio-Chemistry Hot-Cells and between the Radio- Chemsitry Annex and the Positron Emission Tomography program at the UBC hospital. The latter system Is the subject of this paper because of Its unusual length: 2.5 km. It will be used for the transportation of “ 0. ^®N,1*C and ^®F. ^0 has the shortest half life, 2 minutes,which dictates a maximum combined processing and transportation time of approx. 4 minutes. The system was built In 1982 based on tests done in 1979. The paper discusses the results of initial tests and recent commissioning.

BK7 Matching an Isochronous Cyclotron to a Synchrotron to Provide a High Intensity Injector. R. LAXDAL, M.K. CRADDOCK*, W. J0H0**, G.H. MACKENZIE, J.R.RICHARDSON***, L.C. TENG****, TR I UMF. - Schemes are described for Injecting the ~ 1 0 iJ 23 MHz cw H“ beamIn the TRIUMF 500 MeV cyclotron efficiently Into a 30Hz rapid cycling synchrotron. These Involve extraction of 100-200 turn pulses from TRIUMF followed by a multiturn injection (via H” or possibly H° stripping) Into a DC accumulator ring mounted in the synchrotron tunnel. Several novel features would be required In TRIUMF: an increase in the local turn density by an order of magnitude, extraction of H“ ions (rather than protons), and a pulsed extraction system. Turn compaction can be achieved by perturbing either the magnetic field or the dee voltage locally; the RF method is shown to give better matching to the synchrotron RF buckets. An alternative is to build a small Isochronous storage ring to compact several thousand turns.

*Also at Physics Dept., Univ. British Columbia.**0n leave from SIN.***Qn leave from P hys. Dept-, U. of Calif., Los Angeles. ****Fermilab, P.0. Box 500, Batavia, Illinois.

BKS Beam Optics and Extraction from a 12 GeV Isochro­nous Ring Cyclotron. R. BAARTMAN, R. LAXDAL, R. LEE,G.H. MACKENZIE, T R IUMF. - This paper discusses the toler- ence and operational techniques required by isochronous cyclotrons accelerating protons to kaon and p produc­ing energies. The beam traverses many more imperfection resonances and low order intrinsic resonances than In ex­isting cyclotrons since the isochronous radial tune νΓ*γ. With 25 or 50 MeV/turn, the turns will overlap at the outside and the net accelerating voltage must be flat topped to ensure that all particles make the same number of turns. With these conditions a 1 G imperfecti­on at the final Integer resonance developes 3 mm coherent amplitude; and although some non-linear stretching takes place, a clear space of 0.8 mm permits Insertion of a septum. To preserve 1 mm amplitude the operation Im­

perfection fields at other resonance must be less than0.03 G and 0.02 G/mm. Third order Intrinsic resonances will cause some filamentation and impair extraction effi­ciency, although this can be partialy controlled. The placement of accelerating cavities and means to meet the tolerances above and those imposed by vertical and coupl­ed motion will also be discussed.

BK9 Magnet Sector Design for High Energy Superconducting Cyclotrons. J.I.M. B0TMAN, M.K. CRADDOCK*, C.J. KOST, J.R. RICHARDSON**, TRIUMF. - Pole shape designs are presented which maintain focused and Isochronous orbits In the two stages of a superconducting ring cyclotron kaon factory. The first stage of 15 sectors takes a 100 pA proton beam extracted from TRIUMF to 3.5 GeV. The second stage of 42 sectors continues the acceleration to 15 GeV. The orbit properties have been determined using a median plane magnetic field computed from the current distribution in the coils and in current sheets simulating the saturated steel. The design process and the effects of various factors, Including softness of the field edges, cross-section of the coils and negative field gullies will be described.

*Also at Physics Dept., Univ. of British Columbia.**0n leave from Physics Dept·, Univ. of California at Los Angeles.

BK10 A Fast Hodoscope with dE/dx, time and position informa tion. P 7 BROUWER & M. SALOMON, TRIUMF. - We have designed and built a fast scintillator hodoscope using RCA4552 photomultipliers. Due to their small size, these tubes allow a large packing density and have very fast output signals. The rise time is 0.7 ns and the pulse width Is 20 ns FWHM. 24 scintillators In two planes over an area of 96mm x 96mm with a space resolution of 8 mm In both x and y directions. Preliminary tests with sources and In the Mil secondary beam at TRIUMF indicate a dE/dx resolution of 25%, which together with the time of flight Information would allow good particle identification.The hodoscope Is capable of operating at a total rate of 10® particles per second-

BK11 The TRIUMF TPC Trigger System- R.A. BURNHAM, M. HASINOFF, J-M POUTISSOU, UBC, D . A . BRYMAN, M.J. LEITCH, I NAVON, T. NUMAO, P. SCHLATTER, U of Victoria & TRIUMF, G. AZUELOS, P. DEPOMNIER, J-P MARTIN, R. POUTISSOU, U_ d_e MONTREAL, A .L. CARTER, D. KESSLER, Carleton U, M.BLECHER, K. GOTOW, VPI & SU, M.S. DIXIT, C.K. HARGROVE,H. MES, J.P. LEGAULT, NRC, J.A. MACDONALD, J. SPULLER, TRIUMF, H.L. ANDERSON, R.J. MCKEE, LASL, C.S. WRIGHT, ]J OF CHICAGA. - The TRIUMF TPC Is currently employed In a search for electrons of around 100 MeV/c from neutrinoless p” -*e conversion. The experimental trigger should select events around the momenta of Interest and at the high stopping rates encountered (~10® p“ /sec) ensure that spurious background triggers do not generate excessive dead time. It must also determine the end points of particle trajectories with sufficient accuracy to (a) determine which regions of the TPC should fire and (b) select the time sequence of ionization e~ arriving at the TPC endplane detectors (to exclude out-of-time background). A hybrid system of scintillation counters and wire chambers has been developed to meet these requirements.

BK12 Asymmetric Spectrometers for B-Polarimctry* D. MORRIS and D.A.L. PAUL, Physics D e partment. Univ. of Toronto M5S 1A7 - The objective of this study is to transmit the maximum fraction of the continuous (i- spectrum of a small source onto the entrance of a pola­riméter without change of the longitudinal polarization. The beam must converge on the polariméter in a bundle of

36

at most a few degrees half-angle. Thus the spectrometer must have a short object distance and long image dis­tance. We have studied this problem theoretically for sector spectrometers and experimentally for lenses (see next paper). The sector offers the advantage of easily predictable properties apart from fringing field effects which turn out to be of major importance, and have been approximately calculated. A single sector having a 20° gap has been designed which would have a transmission of1.8% of 4π. A three-gap version could in principle yield 5.4% transmission but presents additional problems in its realization. The spectrometer has an image/object distance ratio of 13 as compared with 1.0 in conven­tional designs.*Supported by NSERC grant //A2224

Two-lens spectrometer for 6 polarimetrv* D. H0LDSW0RTH and D.A.L. PAUL, Physics Department. Univ. of Toronto M5S 1A7 - The two lens spectrometer offers an alternative to the sector spectrometer of the previous paper, but is more easily investigated experimentally than theoretically. We have built a test spectrometer having four essential degrees of freedom which can be varied to optimize the transmission. We use iron-clad magnet coils of 15 cm effective inside diameter. Within the limits of our primary magnet field, the optimized transmission T(% of 4n steradians) increases as the source is advanced through the magnet towards the polariméter, approximately according to T=5.7 exp(z/l0.5) where z is in cm, measured from the position of peak axial field. When the source-image distance is 1.8 m the optimum separation of the peak axial fields of the magnets is 67+1 cm, and it does not matter whether the fields are parallel or antiparallel. The maximum half angle of convergence is 4.1°.*Supported by NSERC grant A2224

BK14 Properties of the Coaxial Coupled Linear Accelerator Structured d.-p. LAbKiL a7v3 d. McKtuWN, AECL, Chalk River Nuclear Laboratories, Chalk River, Ontario, Canada KOJ 1J0 - Standing wave linear acceler­ators usually consist of a series of cylindrical reso­nators coupled together and excited in a TMq jq- like mode from a single location. Better electro­magnetic field stability is obtained when such a system is driven in the π/2 normal mode where alternate reso­nators only couple the rf power. A new accelerator structure has been developed in which cylindrical reso­nators are alternately coupled with coaxial resonators excited in a TEM mode. This chain of two different type of resonators allows electromagnetic fields with different spatial distribution to couple together and produce the structure's fundamental mode. The electro­magnetic mode selectivity of the device reduces significantly the propagation of higher order modes throughout the structure. Its mechanical stability has been studied for high average power use and thermal detuning is less than in a similar structure in which the same electromagnetic mode is used. The coaxial coupled structure is a prime candidate for application in microtrons and in x-ray devices operating in regions of high mechanical stress.

BK15 Low Frequency N o ise in SQUID Biogradiometers.J. VRBA, CTF Systems Inc. - Highly sensitive SQUID biomagnetometers (or rock magnetometers) are often operated in an open laboratory environment. Such devices are usually constructed as 2nd or 3rd order spatial gradiometers in order to minimize the effects of environmental noise. However, even the best devices are subject to "low frequency noise" which limits their resolution. Thus a complete description of this low frequency noise is an important part of any magnetometer specifications. Low frequency noise has been observed in a variety of instruments under varying conditions and its behaviour was described empirically. Inferences as to the origin of the low frequency noise for some instruments are discussed. An analysis of low frequency

noise was used to calculate the expected noise magnitude in a given bandwidth and the calculated result was compared with experimental measurements. Agreement was found to be satisfactory.

BK16 Photothermal Methods Applied to the Measurements of Material Thermal Properties. G.ROUSSET and L .BERTRAND Ecole Polytechnique de Montréal - These methods measure indirectly the periodic variations of the sample surface temperature without contact and without perturbation in the periodic thermal field. They lead to the determina­tion of the sample thermal diffusivity by the study of the temperature frequency dependence of the sample face opposite to the periodic incident illumination. Two dif­ferent detection methods can be used. The photoacoustic detection uses a microphone. The pressure signal depends on the heat diffusion in the gas within the photoacoustic cell and on the sample thermal dilatation . The fre­quency range is chosen to minimize the influence of this second term. The second detection method uses the "mira­ge effect" · The laser beam deflection in the gas layer close to the sample is detected by a position sensor. The resulting signal is proportional to the periodic tempera­ture gradient in the gas and is independent of the sample displacements. We discuss here both the theoritical m o ­del and the experiments results for these two methods.

1. P. Charpentier et al , J. Appl. Phys. 53,608 {1982).2. A.C. Boccara et al , Appl. Phys. Lett.36,130 (1980).

BK17 TntercomDarison of Some Commercially Available Calibrated Temperature Sensors Over The Temperature Range 4 to~293 K .* R.F. HARRIS-LOWE and R . R . TURKINGTON, Royal Military College of Canada, Kingston, Ontario. Temperature sensors were embedded in a special 0FHC copper anchor block mounted in a cryostat enabling temperature variation over the range 4.2 K to 293 K. Three of the temperature sensors tested were supplied commercially: a Silicon Diode; a Platinum ResistanceThermometer and a Germanium Thermometer. In addition we tested two Gold Chromel thermocouples fabricated in our laboratory. Results reveal discrepancies can occur between the calibrated results from different sensors. The Platinum and Germanium Resistance Thermometer calibrations were the most reliable. These calibrations were mutually self-consistent over the calibration range and, within an experimental error of 10 m K , successfully predicted reference temperatures produced by liquid helium and liquid nitrogen at their boiling points. In conclusion we feel that it is inadvisable to rely solely upon one calibrated sensor, even if it is checked at one or two reference points.

*Supported by C.R.A.D. 3610-502.

BK18 An Automated Jkilar Cell I-V Measurement and Analysis System.* R. TURNER, C. MOORE, D.E. BR0DIE,

(GWP) t . Waterloo Campus - A microprocessor- controlled current-voltage measurement system, suitable for the characterization of most junction devices and in particular solar cells, has been developed. The analog supply circuit allows measurement in the range of -10++10V and -0.75Ή-0.75Α under standard operating conditions, and a home-built Intel 8088 microcomputer provides automated control and data collection capabilities. Data may also be transferred to an IBM personal computer, where it can be analyzed for characteristic parameters. The overall system allows for rapid, effective I-V curve measurement and analysis and is particularly salted to laboratory device characterization.

*Supported by NSERC and NRC Canada contract.

tGuelph-Waterloo Program for Graduate Work in Physics

3 7

MONDAY, JUNE 27, 1983ROOM 167Chairman: V. Gaizauskas

16:00 Open Discussion on the Canada - France - Hawaii Telescope

MONDAY, JUNE 27, 1983

TIME ROOM

ANNUAL BUSINESS MEETINGS OF CAP DIVISIONS:

16:30 061 Division of Aeronomy and Space Physics16:30 060 Division of Optical Physics16:30 062 Division of Theoretical Physics16:30 160 Division of Industrial and Applied Physics16:30 162 Division of Surface Science

19:30 062 Open Discussion - Formation of a Canadian Institute for Theoretical AstrophysicsChairman: R..N. Henriks en

21:00 166 Meeting of the Advisory Board, CAP Theory Institute (Board members only)

MONDAY, JUNE 27, 1983 JO INT SESSION:ROOM: MacLaurin 144 VLSI FOR THE 80’S, AND

CAP/CAS 1983 CONGRESS

21:00 - 22:00 Overview of VLSI for the 80’s Speakers (2) to be announced

38

TUESDAY, JUNE 28,1983 SOLITONSROOM 168Chairman: G. Dolling

9:00CA1 Aspects of Soliton Behaviour

g . Leibbrandt, V e p t. o ij M athem atics i S t a t i s t i c s , J n tv e A S t ty o i Guetph

Solitons are stable, extended objects whose importance in the mathematical and physical sciences is generally acknowledged now. After a brief historical introduction, we discuss the mathematical origin of solitons and then illustrate the principal features of these fascinating objects in the context of the sine-Gordon and Liouville equations.

9:50CA2 Solitons, Propagating Domain Walls, and Neutron Scattering In One Dimensional Magnetic Systems

S.E. Nagler, I.B.M. - T.J. illation KeseaAch CenteA

The spin dynamics of one-dimensional magnetic systems exhibit important nonlinear effects. In the presence of an applied field, the large arplitude excitations of the planar ferrcmagnet CsNiF, and antiferromagnet 1Î1MC are sine-Gordon solitons. On the other hand, the spin dynamics Ising-liKe antiferromagnets such as CsCoBr, and CsCoCl, are dominated by the propagation of antiferrcmagnetic demain walls in the absence of a field. The contribution of such excitations to the dynamical spin correlation functions can be directly measured by inelastic neutron scattering. This paper describes the observations of solitons in magnetic chains with emphasis on recent experiments on CsCaBr^.

10:30CA3 Solitons with Fractional Charge

S.A. Kivelson, S ta t e U n tv e n s ity o& Mew Voak, S to n y Baook

There has recently been considerable interest provoked by the suggestion that topological excitations (properly kinks) with fractional charge are the lowest energy charged excitations in commensurate one dimensional Peierls insulators. The origin of this fractional charge, and its meaning as a sharp quantum observable will be discussed. Finally, some prospects for experimental observation of fractional charges are explored.

TUESDAY, JUNE 28,1983 PARTICLE P H YSIC S IROOM 162Chairmen: R. M i g n e r o n

G. Karl

9 : 0 0CB1 Grand Unification and Supersymmetry

S. Rudaz, JniveMtty o& Minnesota

9 : 5 0CB2 Search for Massive Neutrinos

M. Dixit, National Rc& catch Council o£ Canada

10:25 Break

10:45CB3 In Search of Jets

S. Ellis, UvuuviUAíf o{J Wa&kington

1 1 : 3 5CB4 The Discovery of the W Intermediate Vector Bosons

A. Astbury, CERW, Su litzeA ta n d and TKIUMF, Vane.ou.veA

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39

A TOMIC AND MOLECULAR PRO CESSES IN ASTROPHYSICAL SOURCES

9 : 0 0CCI Atomic and Molecular Physics in Astrophysical Sources

A. Dalgarno, HakvaAd-SmltiUOyiian CuntAo, (ok fatkophyAlùA

TUESDAY, JUNE 28,1983ROOM 167Chairman: E.J. Knystautas

Recent studies are described of basic atomic and molecular processes that understanding of astronomical phenomena and attention is drawn to some of certainties and their effects on the analysis of observational data. The include charge transfer of multiply-charged ions, dissociative recombinat and collision-induced dissociation.

are relevant to the the most critical un­processes discussed

ion, photodissociation

9 : 4 5CC2 Molecules as Probes of the Physics of Star-Forming Regions

B. Turner, National Radio k^Viommy ObbWJCutoky

10:30CC3 Long Chain Carbon Molecules in Interstellar Space

J.M. MacLeod, HnkzboAQ institute. 0( kltkOphyblCÀ - NRC

T h e 1o n g - c h ai n c a rb on m 01e c u l e s k 0c n as t h e c y ­ no poiyy n e s (H C N ,n - 3 ,5 , 7 , 9 ,11 )ar e f o u n d i n a gr 0¥ i n g n u m b e r 0 f c o o 1 da rk d u st c 1o u d s i n i n t e r s t e 11 ar s p a c eI n ad d i t i 0n , t h e y a re P r e s e n t i n t h e e x p an di n g m ol e c u 1 a r e n V e 10P e su r r o u n d i n gth e c a r b on s t a r I PC 10 216 . Th e tVO 1a r g es t c y an op o l y y n e s k n ov n , N a n dHC 11N , h a v e n 0t y et b e e n s y n t h e s i z e d i n t e r r e s t r i a 1 lab 0r a t 0r i e s , s 6 w h a t i skn o w n ab ou t t h em i s b a s e d o n l y 0n ob s e r v at i 0n s 0 f t h e i n t e r s t e 11a r s pe c i e s .Pr o p e rt i e s o f t h e 1i g h t e r m e m b e r s of t h e f am i i y . H C 3N , H C 5N a n d H N w i l l b ed i s cu s s e d , an t th ei r u se f u l n e s s a s p r o b e s of m o l e c u l a r c 10u d s w i 11 b e o u t 1 i n e d .Fi n a l 1 y , r e ce π t d et ec t i o n s o f tV0 n e w in te r st e l l ar m o l e c u 1e s V h i c h a re r e l a t e dt 0 t h e c y a n op 0iyy ne s , C H 3 C 3N a n d CH 3C 1."· w il 1 be P r e s en t e d

11:15CC4 Atomic and Molecular Processes in Planetary Atmospheres

J.C. McConnell, Vokk liYilVQJUilty

40

9:00CD1 Nuclear Spin Determination Without Tears

J.A. Cameron, McMcUsteA a n io z M l ty

Proper measurements of the spins of excited nuclear states depend on the interpretation of the angular distributions of radiations. When this is impracticable, model dependent means are used to attribute spin. A novel method of comparing gamma ray spectra from proton capture resonances will be demonstrated. Measures of similarity from signal correlation are treated using statisti­cal classification methods, particularly multidimensional scaling. Examples of successful and unsuccessful spin assignment will be given.

TUESDAY, JUNE 28,1983ROOM 060Chairman: J.A. Kuehner

9:40CD2 y SR and Positive Muon Spectroscopy (at TRIUMF)

D.G. Fleming, U n tv V U ity o£ S n i tU h C oùm bta

Since the discovery of parity violation oyer 25 years ago, the muon (μ~) has been utilized in studies of weak, interaction physics vu -*e vv). More recently, particularly in the last 5 years or so with the advent of the world's "meson factories” (TRIUMF, SIN, LAMPF) the muon has been used as a probe of the basic properties of matter in fields of atomic and molecular physics, solid state physics, chemical physics and physical chemistry, in addition to the well established utility of the negative muon for studies in nuclear physics. This diversity of interest is in­herent in the acronym used to describe this field of "applied" muon physics, uSR, standing for Muon Spin Rotation (or Relaxation, or Resonance), defined in analogy with the more established fields of NMR or ESR. In the interests of time my talk, will focus on the positive muon, which unlike the negative muon, shuns the nuclear charge, thus yielding information of a completely different nature; in particular, it often forms the muonium atom (Mu=P+e“ ) as a consequence of its thermallzatlon processes. Indeed, the positive muon acts in matter just like an ultralight proton (M “ 1/9 M.) and much of the interest in the p+ SR field lies in exploring this unpreceden­ted mass difference; eg, in the study of (quantum) diffusion phenomena in solids and of chemical reaction dynamics in both gases and liquids. In the field of magnetism the positive muon pro­vides what may well be a unique probe of lnterstital spin densities and of dynamic magnetic re­laxation effects, particularly in the study of spin glasses. These and other aspects of current interest in the field of "pSR and Positive Muon Spectroscopy” will be reviewed with particular reference being made to the present programme at TRIUMF.

10:25 Break

NUCLEAR P H YSIC S III: SPECTRO SCO PY AND APPLICA TIONS

TUESDAY, JUNE 28,1983 ROOM 060 Chairman: L. Lessard

10:35CEI What Do Scattering Experiments Reveal About The Proton Nucleus Interaction?

T. Drake, U n iw u L ty o& Toronto

Recently the distorted-wave Born approximation (DWBA) has been used with a density-dependent T matrix to explain the "proton-nucleus interaction" with considerable success. Examples will be presented which include recent University of Toronto (?■,: ') data. The framework of the DWBA will be used to illustrate how (?,p') scattering measurements at TRIUMF (<£p = 200-500 MeV), may well reveal unexpected surprises.

11:20CE2 The Case for P.A.U.L.I.

J.s.c. McKee, UniveAAity of, Manitoba

NUCLEAR P H YSIC S IV: SCA TTERING AND A CCELERA TORS

The preliminary design study of a separated sector cyclotron capable of accelerating polarised and unpolarised light ions_with energy versatility and high intensity has been completed. The energy range is up to 120 MeV for Hg, H*, D and D*, to 60 MeV/η for Z/A of 0.5 (such as Li^ ions), and to 44 MeV/r. for L i7 (polarized and unpolarised). The objective was the construction of a high current and/or high resolution facility for nuclear reaction and polarisation studies. Evidence of the need for such stucies will be presented. Secondary features of the facility will be high intensity neutron beams and high quality polarised neutron beams. It is believed that in the field of light ion studies this machine can perform a unique role because of the beam currents available and the concentration on light ion physics. Irrespective of the inherent importance of the physics to be performed with the machine, the importance of the physics to be performed with the machine, the importance of minimizing cost has not been overlooked.

41

9:00CF1 Lower Hybrid Current Drive on Tokamaks

M. Porkoláb, MIT and Plcum Fui-ion Center

9:45CF2 Tritium Aspects of Fusion

D.P. Dautovich, Canadian Fiúdon Fueli Technology Project, Ontario Hydro

TUESDAY, JUNE 28,1983 FUSION PHYSICS IROOM 061Chairman: B.C. Gregory

In theory there are many possible fuel cycles involving the isotopes of hydrogen, helium, lithium and beryllium. Many of these cycles are free of neutrons and tritium and would permit energy recovery through magneto-hydrodynamic processes and they offer great future promise. The reaction which shows greatest promise for early develooment however, involves tritium and produces neutrons,D + T = ^He + n. This reaction has provided an avenue for Canada through the Canadian Fusion Fuels Technology Project to bring to fusion development, both tritium and the technology that we developed to handle it in the CANDU program. The development of fusion involves development of both the physics, and six major technology areas. These technologies include tritium, remote handling, super conducting magnets, breeding blankets, materials and, safety and the environment. There are some aspects of tritium in all of these apart from superconducting magnet technology. This paper will discuss the tritium aspects of these technologies with specific reference to the opportunities for supplying CANDU tritium for fusion research; breeding blanket development; tritium-material interactions including the first wall; the occupational and environmental aspects of tritium; and tritium handling and monitoring aspects. The presentation will include discussion of technology developed previously in the fission program and current developments underway as part of the Canadian Fusion Fuels Technology Project.

TUESDAY, JUNE 28, 1983 FUSION P H YSIC S llROOM 061Chairman: J. Teichmann

Details of the following papers will be given at the poster session.

10:45CGI Plasma-Surface Interactions and Fusion FuelHandling. A. A. HAA S Z , P. C. STANGEBY and 0. AUCIELLO, Univ. of Tor. Inst, for Aero. Studies - Plasma-surface interactions occurring in magnetic fusion devices lead to accelerated uptake and permeation of hydrogen iso­topes in the walls and to the generation of impurity gases fouling the re-cycle loop. Recent Group work is reviewed in two parts: (a) field work on foreign tokamaks (b) laboratory simulation at UTIAS. The tokamak edge studies employ a new diagnostic: the combined Langmuir probe/bolometer which can measure n e , Te> T £ and edge electric fields in real time. The simulation research includes CH^ production from graph­ite and carbide coatings under electron, H° atom, and combined H°/e impact (synergistic studies). Results of retention of H°/D° in graphite are also reported. New simulation facilities are described: H°-beam sources, a laser thermal desorption facility, a permeation membrane facility, a low-voltage high-current mass- analysed hydrogenic ion accelerator (% 0.1 mA/cm~ @ 300eV), a Molecular Beam Epitaxial (MBE) unit.

11:10CG2 STOR-M for Heating S tudies. A HIROSE, 0. MITARI and H.M. SKARSGARD, Univ. of Sask. - Design details of STOR-M tokamak are given. The principal parameters are major radius 46 cm, minor radius (plasma) 12 cm, tor­oidal magnetic field 12 KG (360 KJ bank), OH current 75 KA (q=2.5), and turbulent heating current 100 KA.An iron-core transformer (0.2 V ’sec) will be used to drive OH current. The image field of plasma current due to the presence of iron-core transformer can amount to 50% of the vertical magnetic field required for equilib­rium. During turbulent heating (50 ysec), the vacuum chamber (4 mm stainless steel) will act as a shell. Toroidal field coils (16 in total) are supported by a stainless steel shell structure, the scheme similar to that employed in TEXTOR. Because of high voltage turbulent heating, special toroidal breaks consisting of ceramic rings have been designed.

^Sponsored by NSERC.

42

TUESDAY, JUNE 28,1983 P H YSIC S EDUCA TIONROOM 062 Chairman: W. Brouwer9:00-11:00

THE FUTURE OF PHYSICS TEACHING IN CANADA- A Panel Discussion on the Science Council of Canada Study on Science Education -

The Science Council Study on Science Education has developed a number of position papers on possible future trends in Canadian science classrooms. These position papers have been widely discussed across Canada and reactions to these discussion papers are currently being analyzed by the Study Committee. Recommendations regarding the future of science teaching in Canada should be forthcoming during the spring and summer of 1983. The Physics Education Division of CAP hopes to prepare a position paper on the future of physics teaching in Canada and hopes that today's panel discussion and audience reaction will contribute to such a position paper.

CHI The Science Council Study on Science Education and its Recommendations.B. Robertson, UvU.veA6l£y 0& RzgA.nCL

CH2 Social Issues in Canadian Physics ClassroomsM.W. Ovenden, U uL ve/U lty 0& BsU£i&h Columbia.

Glen Aikenhead, in his Discussion Paper for the Science Council of Canada,focussed on science-related social issues (such as the use and interpretation of breathalizer readings in driving offences), and the misunderstandings and false expectations of science; on the part of administrators and the general public. He proposed the general use of a course on "Different Ways of Knowing" in which the strengths and limitations of science would be disussed within the wider context of other knowledge-systems,such as philosophy and religion.From his experience, he claimed that such material could be presented suc­cessfully in Grade 10.Problems arise in meshing such a course into a structured education in science, both at high school and university. A science student should leave his introduction to the philosophy of science until a later stage in his education, go that its significance may be more deeply apprec­iated.There are other types of science-related social issues: e.g. social pressures & sanctions which determine the direction of scientific research; the fundamental 'ethical’ position involved in doing science; etc.There is need to introduce, both at high school and university, considered and unbiassed teaching about science; but there is an inevitable tension between this requirement and the need to teach science itself.

CH3 Women in Physics: Why Not?A. Gower, U nlveA A lty ojJ V ic to r ia

C h 4 More Canadian Technological Applications in High School Physics?G. Rostoker, UtiLveA&lty ofa klbQJvtCL

One often hears complaints that science is taught at the elementary and post-secondary school levels in a fashion which gives students no immediate feeling for the applications in real life of the material which they are being taught. In this talk, it will be acknowledged that modern course material might well be usefully injected into the curriculum for students in the elementary and secondary school system which would accentuate the usefulness of the information they are being taught vis à vis the Canadian environment. It would be a mistake, however, if this new information were to reduce the amount of time the students spend learning how to use the scientific method and how to operate with the mathematical tools utilized by natural scientists. It will be suggested that, of the many changes that must occur in the school and home environments to make the acquisition of an education in the sciences a desirable commodity, alteration of the curriculum to incorporate more information on Canadian technological applications should rate a low priority in the minds of the planners of our education system.

11:00 Annual Business Meeting of the Division of Physics Education

43

TUESDAY, JUNE 28. 1983 ASTR O N O M Y AND ASTRO PH YSIC SROOM 167Chairmen: D.R. Bochonko

E.R. Seaquist

13:30DAI

Deep CCD Photometry of the Globular Cluster M4.

Harvey B. Richer and Gregory G. Fahlman, University of British Columbia.

A colour-magnitude diagram of M4 has been constructed from CTIO CCD frames reaching to V=24. From this data we discuss the fundamental parameters for this globular cluster.

13:45DA2 The Globular Cluster System in NGC 4594 (The

Sombrero Galaxy) . W.E.Harris, M cMaster U ., H.C.Harris, McMaster U ., and G.L.H.Harris, U. Waterloo. - The luminous, edge-on Sombrero galaxy, a classic Sa system, has an extensive globular cluster population and provides an exceptional opportunity to study key aspects of cluster systems in disk galaxies generally. We have carried out star counts on a deep CTIO 4-m V plate, down to V(lim)^i 23.1 and from 1 to 20 arcmin around NGC 4594. The averaged counts give an exceptionally well defined radial profile for the cluster system, which accurately matches the distribution of halo light (I ~ γ “*) except for the innermost (r<- 2 arcmin) ring. Additional counts on a deep U plate which penetrate further into the nuclear bulge confirm a deficiency of clusters there by a factor of ~ 1.5 to 2 with respect to the halo light, and indicate that this may represent a real difference between these two types of halo stellar populations. The total counted cluster population brighter than Vs=23.1 is (1200±100), yielding a specific frequency (i.e. number of clusters per unit halo luminosity) of S = 2.5 ±0.5, virtually independent of the assumed distance. This S-value is a factor of 2 lower than for a typical elliptical galaxy.

.14:00D A3 Observations of the Nuclear Region of NGC2903

ZORÁN NINKOV UBC - it was first noticed by Morgan (PASP 1958) that a significant subfraction of Sb galaxies exhibit complex or hot spot structure near their nucleus. Probably the most outstanding example of this phenomenon is NGC 2903 which has about 5 very bright regions clustered around the position of the nucleus. CCD observations of this interesting nuclear region will be presented as well as IUE spectra of the hot spots.

14:15DA4 FIELD COLOR-MAGNITUDE DIAGRAMS

IN THE LARGE MAGELLANIC CLOUD Eduardo Hardy and Daniel Durand

Université Laval, Québec

We have used profile-deconvolution techniques to construct a faint very rich (~18,000 stars) color-magni­tude diagram in the Large Magellanic Cloud bar. Analy­sis of the morphology of the diagram combined with core­helium-burning models for the clump red giants indicate that : (1) Stellar formation is an ongoing process, (2) an old population II is not a significant contributor to the bar and, (3) the bulk of star formation may have started as late as one billion years or as early as three billion years ago.

A similar diagram for nearly 30,000 stars was cons­tructed in the periphery of the LMC 9 Kpc away from the center and it is used to compare the population struc­ture there with that of the bar and with that of other regions.

14:30

183 GHz Water Line Variation in Orion:* T. B. H. KUIPER, D. F. DICKINSON, M. J. KLEIN, P. N. SWANSON, P. ZIMMERMAN, JPL, C a ltech - Airborne observations of the 3(1,3) - 2(2,0) transition of water vapour in the direction of Ori MCI in February, 1980, showed an increase of nearly a factor of two and an apparent red- shift of approximately 2 km/s compared to the profiles observed in 1976 and 1977. We attribute this to the appearance of a new component at a velocity of 12 km/s with respect to the local standard of rest. The new component also has broad wings which were found in the previous observations and in other molecular lines observed from this source. A possible connection between this increase and the dramatic increase of the 7.5 km/s feature in the 22 GHz profile observed in the fall of 1979 is explored. Implications for the previous estimates of the abundance of water in the Orion molecular cloud complex will be considered.

* The research described in this paper was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

14:45DA6 Radio Brightening of HM Sagittae

C.R. PURT0N, n.R.A.O., Penticton, Sun KWOK and P.A. FELDMAN, H.I.A., Ottawa - Radio data for the peculiar emission-Iine star HM Sge are presented which illustrate the brightening seen at all frequencies during the epoch 1977-80. The radio data are compatable with a model based on interacting stellar winds (Kwok, Purton and FitzGerald, Ap. J. 219, L125, 1978). The model does not give the distance unambiguously. Model parameters chosen to match the optical observations of Wallerstein (PASP 90, 36, 1978) yield a distance of -380 pc, but luminosity arguments suggest a distance of ~2 kpc.

15:00

_ DA7 Star Formation Regions - their GalacticDistribution Assessed from New OH Maser SurveysJ * L· Caswell and r ,f . Haynes , lsiro Radiophysics, Epping, Australia - Certain varieties ot oh masers are— intimately associated with regions of recent star formation. They are especially useful probes of galactic structure because (i) obscuration is negligible in the microwave band where they emit (ii) many have high luminosities permitting detection to the edge of the galaxy (iii) their radial velocities provide distance measurements. Here we use new OH surveys from the Parkes radio telescope, that cover much of the galactic plane, to determine the distribution of star formation regions as a function of distance from the galactic centre. We find (i) an enhanced density between 5 and 8 kpc from the centre (ii) an enhanced density near the centre itself (R< 1 kpc) and (iii) a small but appreciable density extending beyond the solar circle.

15:15DA8 A New Look at Pulsar Statistics. SERGE PINEAULT,

Université Laval - The distribution, in galactic longi­tude and z distance, of the periods and period derivati­ves of the full sample of over 300 pulsars are analysed. It is found that subsamples of different galactic longi­tude range and mean height above the galactic plane have statistically significantly different distributions. On the basis of these results, a mean vertical velocity of

44

motion is estimated for pulsars as a whole and the possi­ble relevance of selection effects on both distributions is discussed.

15:30 Break

15:45DA9 Measurements of Magnetic Fields in Late-Type

Dwarfs , DAVID F. GRAY, Univ. of Western O n t . - Direct * Vmeasurements of stellar magnetic fields will help us tie together the phenomena of rotational braking, mass-loss, chromospheres, coronae, star spots, magnetic cycles, and dynamo generators. I have measured Zeeman broaden­ing in the orange spectral region of several G and K stars. The observed broadening is a small fraction of the turbulence and rotational broadening. I will show why, in such cases, it is not possible to obtain the distribution of field strengths, and even the simpler case of disentangling a characteristic field strength from the fraction of the stellar disc covered by that strength field is itself a sizeable challenge. A technique will be described which employs the leverage of several spectral lines directly in the Fourier transform domain. M a tched pairs of lines are not required. Random errors in the amount of Zeeman broad­ening can be as small as + 10%. Magnetic fields are seen in dwarfs cooler than G8. For example, ε Eri (KOV) shows a field of 950 + 85 gauss, assuming a purely longitudinal field covers the full stellar disc.

16:00DA10 Spectropolarimetry of the Semi-Regular Variable

V C V n , MICHAEL S. JEWISON, L.A. TOMASZEWSKI, J.D. LAND- STREET, U . W . O . - Spectropolarimetric observations have been made of the SRa variable V Canum Venatoricum. The percentage polarization in the blue-visual spectral region is observed to vary from l%-2% at maximum light up to as much as 8%-10% near some (but not all) minima. Very large variations in percentage polarization across the TiO bands are present during episodes of maximum polarization. As the star approaches minimum polari­zation these variations tend to disappear. The polari­zation is interpreted as resulting from scatterers that are well mixed with absorbers in the outer atmosphere of the star, at least during episodes of high polari­zation.

16:15DA11 Recogn ition of the Scientific Work of Balfour

Currie and Frank Davies, J. E. KENNEDY, U. OF SASK. - A plaque, to be mounted in the Physics Building, University of Saskatchewan, will be unveiled in the fall of 1983 to honour the outstanding scientific work of Balfour Watson Currie and Frank Thomas Davies while they were stationed at Chesterfield Inlet during the Second International Polar Year, 1932-33. Their field measurements, followed by a careful reduction of the data on the aurora borealis, geomagnetism and the Arctic atmosphere added significantly to the basic understanding of these phenomena. Recently, some of their observations and findings have been re-examined and it is now possible, in retrospect, to perceive clearly the importance of their work. In this paper, an assessment will be made of the contribution of Balfour Currie and Frank Davies to the knowledge of the above related fields, arising from the program carried out during the Second International Polar Year.

16:30DAI2 A Recalibration of the H t Absolute Magnitude

Relation With High Signal-to-Noise Reticon Spectra C.G. MILLWARD ancT G.aTh. WALKER UBC - High signal-to- noise Reticon spectra of 71 of the brightest members in the Pleiades, Alpha Persei, NGC 2244, NGC 2264, the Ursa Major cluster, Orion OBI, Cepheus 0B3, and Cygnus 0B7 have been used to recalibrate the Hr absolute magnitude relation. The calibration has been zeroed with early A-type stars with reliable trigonometric parallaxes, visual binaries composed of an early- type primary and a late-type secondary, and eclipsing binaries with well determined dimensions. The zero point stars have also been used to help define the shape of the relation. The new empirical calibiation is applicable to luminosity classes III-V and has a mean probable dispersion of +0.28 mag. No spectral type corrections are necessary. The present calibration averages 0.1 mag. fainter than the Balona $ Crs.mpton (1974) calibration and averages 0.4 mag. fainter than the Blaauw (1963) calibration over the spectral range 06-B1. Exact stellar spectral types are not needed when using the new calibration. The Hr distance modulus found for NGC 2244 (11.07) is in excellent agreement with other determinations.

16:45DA13 Collision-Induced Absorption in the Far

Infrared Spectrum of Titan. J. D. POLL and J. L. HUNT, Univ. of Guelph, D. GOORVITCH, Ames Research Center, R. H. TIPPING, Air Force Geophysics Laboratory - We have investigated the effect of collision-induced absorption in the far infrared spectrum of Titan. After a review of the procedure for the theoretical calculation of the N2 translation-rotational spectrum, new results for the temperature range of 70 to 120K are reported. These are used as input data for a simple atmospheric model in order to compute the far infrared radiance, brightness temperature, and spectral limb function. This source of opacity alone is not capable of explaining the Voyager results. When the collision-induced methane is included, the results are in closer agreement In the range between 200 and 300 cm“ ^, suggesting that a more complete treatment of collision-induced absorption including particularly CH^-N2» N2-H'. and H2-H2 results, may provide sufficient opacity to reduce or obviate the need for opacities due to clouds or aerosols in order to explain the observed spectra.

17:00DA14 The Cyanogen Bands of Comet Halley. J.B. TATUM

and E.C. CAMPBELL. John L. C limenhaea Observatory, University of Victoria - The profile of the 388.3 nm CN band, excited by the Swings fluorescence process, is calculated for Comet Halley for every half-day from 200 days perihelion to 200 days postperihelion, using high- resolution wholedisc solar irradiation spectra supplied by Kitt Peak National Observatory.

17:15DA15 Orbital Elements of 93 Leonis. A.H.BATTEN,

W.A.FISHER, J.M.FLETCHER and G.HILL Dom. Astroihys. Obs. (H.I.A.) Victoria- High-dispersion spectrograms have been used to revise the orbital elements of 93 Leonis, a spectroscopic binary with a composite (A+G) spectrum.A subtraction technique has been developed that enables the early-type spectrum to be measured for the first time, thus providing values for the velocities of both component stars. Minimum masses of the stars are about O.9m0 and 1.Om0 , the G-type star being tie more massive. Positions of the components in the H-R diagram are consistent with an evolutionary age of 109 years, and an initial composition Y=0.2, 2*0.01.

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TUESDAY, JUNE 28, 1983 P H YSIC S EDUCATION WORKSHOPROOM 128a

13:30DB1 u se 0 f Microcomputers as Data Acquisition Systems in the Physics Classrooms.

L.P. Robertson and D.E. Stenton, ünÀ.VÇA6Cty 0& Và,cX oHajX

The workshop will emphasize the use of a microcomputer in a data acquisition system. A brief summary of the concepts of digital and analogue input to and output from a microcomputer will be given followed by a demonstration of a number of microcomputer based data acquisition systems. Examples will be selected from high school physics experiments. Participants should have a working understanding of a microcomputer operating system and a high level language (BASIC preferred). Enrollment will be limited to 20 people and the workshop is primarily directed to teachers of senior high school physics.

There will be a registration fee of $15 to cover the cost of resource material supplied at the workshop.

This workshop moved to Wednesday, June 29, 13:30. Room 139

TUESDAY, JUNE 28, 1983

13:30-14:30 Poster Festival-Part II Festival de séances de démonstration-Deuxième partie

ROOM 136

MAGNETIC PROPERTIES OF SO LID S

DC1 Paramagnetic to spin-glass transitiontemperatures in Cdv Zn..Mn7T e . T. DONOFRIO, G. LAMARCHE, A. MANOOGIAN and J.C. WOOLLEY, Physics Department, University of Ottaw a , Ottawa, O n tario - We report on the low field magnetic susceptibility of Cdx ZnyMnzTe where x + y + z = 1 in the range 4.2 < Ί < 100 K. For Mn concentration .25 - z - .70 these alloys show a paramagnetic behaviour above, and a spin-glass one, below a critical temperature Tc characteristic not only of the Mn concentration z, but also of the C d , x and Z n , y contents. We found Tc to increase smoothly as (x, y) passes from (1 - z, 0) to (0 , 1 - z) for fixed z as follows: for z = 0.30, T c varies from 7.1 to 9.5 K, for z = 0.40, from 12 to 15 K and for z = 0.6 from 27 to 30 K. Our data for x = 0, for y * 0 and for x = y fit separately a phenomenological relationship proposed recently by Escorne et alV^' where log Tc is expected to scale with

^M. Escorne, A. Mauger, R. Triboulet and J.L. Tholence, Physica 107B, 309 (1981).

D C 2 Magnetostriction in the Spin-density-wave Phase of MnSi. E. FRANUS-MUIR, M.L. PLUMER, V. PLUZHNIKOV andE. FAWCETT, Dept, of Physics, U. of Toronto - Results of using a capacitance method to measure magnetic-field- induced strains at 4.2 K in the cubic metallic compound MnSi will be presented. The anomalous behaviour of magnetostriction along [100] and [ill], for a variety of field directions, can be interpreted as resulting from field-induced changes in the helical spin-density-wave which exists below 29 K. For example, the anisotropy found in the low field (H ^ 1.5 kOe) behaviour arises from a wavevector and spin reorientation occuring for H I J [100] but not for H | J [ill]. The anomaly at the critical field, Hc n, 6.4 kOe, where there is a phase transition to a field-induced ferromagnetic state, is quite pronounced when H || [110]. This work corrobor­ates and extends previous experimental1»2 results and agrees with existing theory3.

Fawcett, J.P. Maita, J.H. Wernick, Intern. J. Mag­netism, 1, 29 (1970).2M. Matsunaga, Y. Ishikawa, T. Nakajima, J. P h . Soc. Japan, 51, 1153 (1982).3M.L. Plumer, M.B. Walker, J. Phys. C., 15, 7181 (1982).

46

Magnetoresistance of PrBc and NdBs.* NAUSHAD ALI and S.B. WOODS, Dept, of Physics, U. of Alberta - The magnetoresistance (m.r.) of single crystals of ΡτΒβ and NdBg has been measured in magnetic fields up to 3 Tesla in the temperature range from 4 to 20 K. Both compounds become anti-ferromagnetic at low temperatures. The Neel temperature T^ of PrBg is 6.99 K and of NdBé is 7.74 K. In the anti-ferromagnetic temperature range the longitudinal and transverse m.r. are positive for both compounds. Immediately above T^ all except the transverse m.r. in PrB6 become negative although within our range of temperature both m.r. components become positive once again in NdB6. The results clearly show an anisotropy in m.r. that decreases with increasing temperature. The anisotropy will be discussed in terms of anisotropy in the interaction between conduction electrons and f-electrons on the rare-earth sites.

*Supported by NSERC.

D C 7 Conduction Electron g-factors in Ru and Os*. V.E. STARTSEV, Institute of Metal Phvsics. USSR Academy of Sciences, P.T. COLERIDGE and Ϊ . Μ . TEMPLETON,Division of Phvsics, NRC, E. FAWCETT, C. MUIR, and J.M. PERZ, University of Toronto - De Haas van Alphen oscillations have been analysed to deduce g-factors in the hexagonal transition metals Ru and Os. The values for orbits normal to [OOOl] on analogous ellipsoids centered on the line LM are 1.75±0.12 and 1.34±0.07, respectively. The more marked suppression of the g-factor in Os, where spin-orbit coupling is stronger, is consistent with recent theoretical studies1 .

^A.H. MacDonald, J. Phys. F: Met. Phys. 12, 2579 (1982)

*Supported by NSERC.

DC4 Transport Properties of Dilute Rare-Earth-Yttrium Alloys.* NAUSHAD ALI and S.B. WOODS, Dept, of Physics, U. of Alberta - The temperature dependence of resistivity and thermoelectric power has been investi­gated in the temperature range of 2 to 30 K. The magne­tic properties1 of these alloys vary from either Rondo or spin-glass2 behaviour to antiferromagnetic ordering at low temperatures depending on the concentration and nature of the rare-earth impurities. We have also done magnetoresistance (transverse as well as longitudinal) studies in a magnetic field up to 3 Tesla. Magneto­resistance is thought to give some information about the antisymmetric scattering between conduction electrons (K) and magnetic f-electrons for impurities with non­zero orbital angular momentum (L=^0) . Anisotropy in magnetoresistance is thought to be mainly due to quadrupolar K-f interaction above magnetic ordering temperature.

Hurd, C.M., Contemp. Phys., 23, 469 (1982).2Ford, P.J., Contemp. Phys.. 23, 141 (1982).

♦Supported by NSERC.

Spin Rotational Invariance and Spin Waves in Itinerant-Electron Ferrqnaqnets.* A.J. PINDOR and A. GRIFFIN, University of Toronto - We discuss the general conditions under which the transverse dynamic spin sus­ceptibility x^_ obtained in the SCF approximation satis­fies spin rotational invariance (SRI). We use a sum r ule1 which relates SRI to the existence o f zero fre­quency spin waves (Goldstone mod e s ) . W e prove that for on-site electron-electron interactions, SRI is indeed satisfied if χ+_ is calculated using the SCF single­particle Green's functions. However, when interactions of finite range are allowed, the SCF equations may not preserve SRI. For a very sinple model of a bounded ferromagnetic metal with on-site interactions and a surface at vhich the electrons specularly scatter, we show that one can achieve SRI. However, in contrast to previous w o r k 1, the resulting spin waves are found to be identical to those of the bulk. In particular, Wg'vq 2 for q ^ O , where q (| is the wavevector parallel to the surface.

‘Guntos,G. and Griffin, A., Surface Science £1, 669 (1980).

♦Work supported by NSERC.

D C6 Solitary wave in deformable Heisenberg ferro- magnet with an easy plane. R. CÔTE and A. CAILLE, Uni­versité de Sherbrooke.- The coupling between acoustic phonons and magnons in a one-dimensional ferromagnet is studied through a dipole-dipole interaction term. It is shown that the non-linear equation of motion obtained can support solitary wave solution under certain restric­tions on the applied field and coupling constant. Appli­cation to the case of CsNiF„ ferromagnet is presented.

Electron Spin Resonance and Crystallography of(Cd, Mn )(Te, Se ) Alloys. S. CHEHAB, B.W. CHAN,1-x x 1-y yA. MANOOGIAN, G. LAMARCHE and J.C. WOOLLEY, Physics Dept. , Univ. of Ottawa - Polycrystalline sampJ.es of the alloys were prepared by a melt and anneal technique. Equilibrium conditions were investigated by standard Debye Scherrer x-ray powder photographs. Hence the various fields of the phase diagram were found and values of lattice parameter determined for the CdTe and CdSe single phase fields. ESR measurements of linewidth ΔΗ as a function of temperature below 300 K were made on the Mn^+ ions of the alloys covering the range of single phase cubic and hexagonal behavior.For x > 0.2, ΔΗ was found to increase with decreasing T, reaching a maximum at a critical temperature T. which is associated with transition to a spin-glass state.For x - 0.2 a different effect occurs and a critical temperature at T < 10 K is observed. Various plots of Tc versus the composition variables were made. The variation of ΔΗ with T could be fitted to the expression ΔΗ = A{TC/(T - T c)}a , and it was found that the o values were close to 0.33 for all the single phase samples.

DC9

The Temperature Dependence (11-293 K) of the Spin Hamil­tonian Parameters Describing the 9 GHz EPR Spectra of Gdi+ Impurity Ions in Y (OH) 3 Monocrystals.H.A „ Buckmaster, V.M. Malhotra and J.M, Bote1er, Dept. of Physics, University of Calgary. - The temperature dependence between 11 - 293 K of the spin Hamiltonian parameters g|f , g^, B2 o, BU0 ' Bb0 anc B 6 6 describing the 9 GHz EPR spectra of Gd3 + impurity ions at C3 symmetry sites in diamagnetic Y (OH) 3 and paramagnetic Eu(OH) 3 monocrystals is reported, it is found that the temperature dependence of B2o and B 4 0 is cubic whereas B5 0 and Βββ are temperature independent. The temper­ature dependence of g and gA permits the nearest-neigh­bour and next-nearest-neighbour paramagnetic interac­tions for Eu3+ ions to be estimated.

1 MALHOTRA, V.M. AND BUCKMASTER, H.A., CAN. J. PHYS.6 0 , 1573 (1982).

*Supported by a NSERC research grant.

DClO Optically Detected Magnetic Resonance in A gBr*. l.J. BOOTH and C . F . SCHWERDTFEGER, Physics Dept., Univ. of B.C. - Observations of optically detected magnetic resonance (ODMR) in AgBr with isoelectronic iodine im­purities is reported. The photoluminescence spectrum of AgBr:I at 4K exhibits two broad emission bands centered at 4900 Â and 5700 A. The 4900 Â luminescence is due to isoelectronic bound excitons at iodine impurities, while the 5700 Â emission is thought to arise from exciton recombination at clusters of silver atoms. A weak iso­topic ODMR signal from the 5700 Â band with a g value of1.8 has been reported.1 The present measurements reveal two signals one at g = 1.81 and a weaker resonance at g = 2.07. The angular dependence and possible origin of the new resonance will be discussed. No ODMR signal associated with the 4900 Â band was observed.

^Hayes W., Owen I.B. and Walker P.J., J. Phys. CIO, 1751 (1979).

*Suppported in part by NSERC of Canada.

DC 11 Spin-Reorientation Induced Soft Mode in MnSiM.L.PLUMER and V V.TARASENKO*, Dept, of Physics, U. of Toronto - The results of using a phenomenological model of spin-lattice relaxation, based on a Landau-type free energy, to describe the interaction of ultrasonic waves and the helical spin-density-wave in the cubic metallic compound MnSi will be presented. The mean-field theory is used to make predictions of anomolous behavior in the sound velocity and sound attenuation near th^ magnetic-field induced wavevector (Q) and spin (sJ q ) reorientation phase transition1 (H -1.5k0e). Arising from a linear çoupling of the order parameter (the angle between Q and H) and shear strains in the free energy, a structural-phase-transition associated soft mode, Cui* (ω-Η))-*0 , is predicted to occur at H-H^·.

1Plumer, M,L. and Walker, M B . , J ( Phys. C 14, 4689 (1981).

*On leave from the Institute of Radio Engineering and Electronics, Academy of Sciences of the USSR, Moscow.

DC12 Radiation Effects of Protons on Samarium-Cobalt Permanent Magnets. E.W. Blackmore, TRIUMF. - At TRIUMF the use of rare-earth cobalt (REC) permanent magnet quadrupoles as the first element in a secondary channel has been studied as a means of increasing the solid angle acceptance of the channel. The anisotropy and other properties of oriented samarium-cobalt magnets can be utilized to produce a high-gradient quadrupole field in an extremely compact magnet. Although many properties of REC material have been measured, little is known about the effect of radiation on the magnetic behaviour. As the TRIUMF appliations require the magnets to operate in a high radiation environment it was considered essential to study this effect. This paper describes the results of exposing samples of samarium-cobalt to a beam of protons .

ROOM 136

PHASE TRANSITIONS, LATTICE DYNAMICS,AND LO W TEMPERATURE P H YSIC S

DD1 Jahn-Teller Peierls Distortion in PrCiLq, D.R. TAYLOR, Queen ’s U , Canada, R.M. MÓRRA and R.L ARMSTRONG, U. of Toronto, Canada. - PrCS,3 is believed to undergo a cooperative Jahn-Teller phase transition1 at 0.4 K, but as yet the low-symmetry phase has not been identified directly. The dominant interaction is an XY pseudospin coupling between nearest neighbour Pr ions which form chains parallel to the hexagonal axis. We have carried out a symmetry analysis of all commensurate phase trans­itions associated with an irreducible representation of the C 6^ space group. The observed continuous splitting2 of the CÜ NOR line into two equal components below 0 4 K is compatible with only two low-symmetry phases: a zone- centre C 1^ structure and a zone-boundary (OO^) C ^ struc­ture , Arguments based on the known interactions and on susceptibility measurements1’2 imply that the low- symmetry structure is C 1^, which retains threefold Pr site symmetry but has alternating long and short Pr-Pr separations along the chains. Hence the phase transition in PrCSi.3 is not the expected ordering of the transverse moments but a pseudospin Peierls distortion

1. J.P. Harrison, J P Hessler, D.R Taylor, Phys Rev. B14, 2979 (1976).

2. J .H . Colwell et al, Phys. Rev 181, 842 (1969).

D D2 Application of Correlated-Effective-Field Theory to the Analysis of Transverse Susceptibility and Critical Behaviour in the Uniaxial Ferromagnet LiHoFi,. J H PAGE, S.R.P. SMITH*, and D.R. TAYLOR, Queen's U . . Canada. —In LiHoF^ the electric susceptibility, which is trans­verse to the magnetic susceptibility, exhibits a sharp cusp at T c which cannot be explained by simple mean-field theory. To interpret our results we have used correlated- effective-field (CEF) theory with a simplified form for the interaction we find that it gives an excellent description of the data over a wide range of temperatures. We have also applied our CEF model to an analysis of critical behaviour in LiHoF^ by re-examining the precise order-parameter data of Griffin et a l..1 Over the tem­perature range of the data, the CEF model gives a fit of comparable quality to that obtained using renormalization group (RG) theory1. Thus the experiments of Griffin et al. do not clearly establish whether the critical exponents in LiHoF^ have a logarithmically-corrected mean-field form as predicted by RG theory with a marginal dimen­sionality of 3, or whether the critical behaviour is ultimately classical, as predicted by the CEF model.

*Permanent address: University of Essex, Colchester, U.K. 1. J A. Griffin et al., Phys. Rev. B22 4370-8 (1980)

DD3 F i r s t and Second O rder M agnetic Phase T r a n s i t ­io n s in Terbium and D ysprosium * . D. A. TINDALL, D a l- hous ie U. and M. O. STEJ.NITZ, S t. F ra n c is X a v ie r U. - Recent re n o rm a liz a t io n -g ro u p c a lc u la t io n s by Barak and W alker^ have suggested th a t th e Neel t r a n s i t io n ( h e l i ­c a l a n tife rro m a g n e t-to -p a ra m a g n e t) in the heavy ra re e a r th m e ta ls shou ld be a f i r s t o rd e r phase t r a n s i t io n . As ou r p re v io u s w ork2 has shown, th is seems to be the case in holm ium. However, we have re c e n t ly made h ig h

48

resolution (1 part per million) thermal expansion measurements on the a-, b- and c-axes of terbium and dysprosium which indicate that the Neel transition of each of these metals is second order.

^Z. Barak and M. B. Walker, Phys. Rev. B25 1969 (1982). 2D. A. Tindall, M. 0. Steinitz and M. L. Plumer, J. Phys. F (Metal Physics) ]_ L263 (1977) .

♦Supported in part by NSERC.

DD4 Superposition of Spontaneous Strains at the *>rro/Paraelec+ric transition on Lattice Imperfection- and Crystal Defect-Related Strains in T . G.S. H .H . SCHLOESSIN, U.of Western Ontario, London, Canada - Sets of x-ray transmission topographs (Lang method), each set taken from one single crystal of T.G.S. (Triglycine sulphate), below, at, and above the Curie temperature, are shown to illustrate the effects of the spontaneous strains on existing strains due to crystal defects, impurities and lattice imperfections. Each set employs several projections with different Bragg-reflecting planes. The spatial relationships between the defect orientations, reciprocal lattice vectors, displacement vector, polarization vector and wave vector are ex­plained in accompanying pole diagrams. The lattice- strain producing defects, identified with the images, include dislocations, stacking faults, impurity inclusions and strain lobes due to crack tip stresses. Traverses across some of the images, in the form of intensity scans, allow some semi-quantitative analysis of the strain magnitudes. Some of the image exposures were obtained with the application of electric or temperature gradients across the crystal with sub­stantial components normal to the Bragg planes.

DD5 Pair Potentials and the Bonding Energy of d-band Metals. A.H. MACDONALD and ROGER TAYLOR, National Research Council of Canada - A method for decomposing the bonding energy of d-band metals into a sum of pair­wise interactions between transition metal ions is presented. The dependence of these pair-potentials on the configuration of the ions is examined by evaluating them for several perfect crystals (sc, bcc, fee and hep). The results indicate that the pair-interactions are not extremely sensitive to the ionic configuration and suggest that the practice of parameterizing the variation of total energy at constant volume in terms of configuration-independent central pair-potentials may have some physical basis.

DD6 Raman and Infrared Spectra o f CrystallineCyanogen.* A. ANDERSON, B. ANDREWS, J.W. LEECH and B.H. TORRIE, (GWP) Waterloo Campust - Results from a Raman and infrared study of solid cyanogen, C 2N 2» at 18K are reported. The intramolecular vibrational region is characterized by multiplet structure of the fundamentals, and the lattice region by an unusually large number of peaks. Principal features are assigned by a group theoretical analysis based on the centrosymmetric orthorhombic structure, with 4 molecules per unit cell. Observed translational and librational frequencies and intensities are compared with lattice dynamics calculations, based on a rigid molecule harmonic model, using Lennard Jones atom-atom potentials.

♦Supported by NSERC of Canada.

tGuelph-Waterloo Program for Graduate Work in Physics.

DD7 Raman and Infrared Spectra of theTrihalomé thanes7* A. ANDERSON, B. ANDREWS, O.S.BINBREKt and B.H. TORRIE, (GWP)2, Waterloo

Campus+ - Recent results of spectroscopic studies of the low temperature solid phases of the trihalomethanes, CHF3, CHCI3, C HBr3 and CHI 3, will be presented, with emphasis on the far infrared and Raman lattice spectra. In those cases where the structure is known, (CHCI3, CHBr3, CHI 3), the spectra will be shown to be consistent with the group-theoretical predictions. The implications of the observed spectra for the possible structure of CHF3 will be discussed. Tentative assignments of the observed spectral features will be given, based on symmetry, frequency and intensity arguments.

♦Supported in part by NSERC of Canada.

tOn leave from the University of Petroleum and Minerals, Dhahran, Saudi Arabia.

+Guelph~Waterloo Program for Graduate Work in Physics.

DDB Optical phonons in the Ga^In^ ^Se system.*

G. SAINTONGE et J.L. BREBNER, Département de physique,Université de Montréal - Single cristals of Ca In, Se,--------------------------- 0 x l-x 1in the gallium rich and indium rich regions, have beengrown by the Bridgman method. Infrared measurements have been performed and their results show that the sys­tem has a two mode behaviour except for x * 0,98 where only the GaSe- like oscillateur is visible. \ Kramers- Kronig analysis has been done, followed by a curve fit of the factorized model of the dielectric constant.From these calculations, the revelent parameters are eva· luated. A model for the behaviour of optical phonons in alloy systems proposed by Jahne is applied at this stu­dy and finally a review of the criteria for the one mode and the two mode behaviour, applied to the Ga In, Se system, is given.

♦Supported by the National Science and Engineering Re­search Council of Canada and by the Ministère de l'Edu­cation du Québec.

DD9 Heat Transfer between Phonons and Quasi­particles in Dilute ^He-HHe Mixtures - A Size Effect.*F. G U ILLŐN,T J.P. HARRISON and A. S ACH RAJ D A Queen's Univ. - Earlier work had shown reasonable agreement between experiment1 and theory2 for heat transfer be­tween phonons and quasiparticles in bulk dilute liquid ^He-3He mixtures. New results for the heat transfer with sintered metal powder in the sample cel.', will be presented for mixtures containing 0.03%, 0.1°' and 0.3% 3H e . Surprisingly, it was found that heat transfer within the helium not in the sinter was increased signi­ficantly by the presence of the sinter in the cell. The results will be compared with the size effects expected from the boundary scattering of the 3He quas;.particles by the subraicron pores in the sinter.

1F . Gui lion et al., Phys. Rev. Lett. 47, 435 (1981).2T. McMullen, J. Low Temp. Phys. 51, 33 (1983).

* Research supported by NSERC and Queen's University School of Graduate Studies and Research.

^Present address: Northwestern Univ., Chicago.

49

DD1U New Model for Kapitza Re sistance between Liquid ^He and Sintered Metal Powder.T J.P. HARRISON, A.R. RUTHERFORD*and M.J. STOTT. Queen's U n i v . - Heat trans­fer between liquid ^He and sintered micron and submicron metal powder heat exchangers is anomalously large near 1 mK. In the past this has been attributed to magnetic coupling. An alternative model has been investigated.It is postulated that at low temperatures the dominant vibrational modes of the sinter are localised oscilla­tions of the powder particles with a constant density of states. The high frequency limit is equal to the low frequency limit of Debye phonons in the small particles. The total number of modes is 3 x number of particles.The ^He is treated as a Fermi liquid in a box the size of a pore with each box a quantum oscillator · Hoc _ is transferred to the helium by the shaking of the box. Applying the Fermi Golden Rule, a value for the heat transfer has been calculated. It has the correct magni­tude and temperature dependence. A check on the model has been a successful comparison of calculated specific heat with the experimental results for sinters of Pohl and T a i t .^]R. Tait, Thesis, Cornell University (1975).^Research supported by NSERC. *NSERC Summer Student.

DD11 Nonequilibrium Superconducting Processes in Tin Microbridges. R. ESCUDERO and H.J.T. SMITH, (GWP)^t, Waterloo Campus - A new experimental technique to fabri­cate superconducting microbridges of accurately known length is described. These microbridges exhibit non­equilibrium effects and the data from the current-voltage characteristic is compared to the theoretical models of Aslamazov-Larkin^^ and Schmid et al^ ). In general, there is qualitative agreement. The deviation of our

^ C l ^ C O V S * T/TC data f rom the theoretical prediction is

discussed.

(1) Aslamazov, L.G. and Larkin, A.I., JETP A3, 698 (1976).

(2) Schmid, A., Schon, G. and Tinkham, M . , Phys. Rev. B21, 5076 (1980).

fGuelph-Waterloo Program for Graduate Work in Physics

DD12 Reduction o f A.C. Losses bv Decrease of the Surface Barrier. M.A.R. LEBLANC, and J.P. LORRAIN, Physics Department, University of Ott a w a , Ottawa KIN 6N5- We report on an extensive computational investigation of the effect of the surface barrier on hysteresis losses. These model calculations reveal that the losses can be substantially diminished by lowering the height of the surface barrier. The calculations were carried out for planar (ribbon) and for cylindrical (wire) geometry with the applied magnetic field directed along the surface(s) of the sample and swept between (i) 0 and H n)ax (half-wave cycle) and (ii) -Hmax (full-wave cycle). We examined the behaviour for amplitudes below and above that required for full penetration of the flux disturbance to the center of the specimen. We have explored the phenomena for two extremal types of bulk pinning, namely the Bean-London (jc = ai) and the Kim-Anderson (jc = a0/B) approximations. We have, for simplicity, assumed that the barrier height is field independent and either symmetric (opposing flux entry and exit equally) or asymmetric (opposing flux entry o n ly). Preliminary calculations show that a surface barrier decreasing with magnetic induction B , accentua tes the effect reported.

ROOM 139

OPTICAL AND ELECTRICAL PROPERTIES OE SO LID S

Dkl a Comparison of Pressed Pellets, Electroplated and Single Crystal Cadmium Selenide Electrochemical Solar Cells, K. C0LB0W, S . WESSEL and A. MACKINTOSH, Dept, of Physics, Simon Fraser U . - The spectral res­ponse, I—V characteristics, and voltage dependence of the quantum efficiency are compared for annealed pressed pellets,electroplated and single crystal cadmium sele­nide electrochemical solar cells. The pressed pellets showed an unexpectedly good solar response which we attribute to a relatively low impurity concentration. Physical properties such as density, resistivity and surface morphology were determined and related to solar cell performance via wavelength response, quantum efficiency, and white light current-voltage character­istics = The spectral response indicated a bandgap of 1 7eV Pellets pressed at higher pressure showed an improved quantum efficiency Pressures above 69MPa produced fractures in the pellets. Vacuum annealed single crystals showed unusual spectral response parti­cularly in the présence of simultaneous laser excitation at 638mm, which we attribute to recombination states near the surface.

DE2 Electret-Semiconductor Solar Cell*. A. FILION, M.M. PERLMAN, V. GELFANDBEIN, B. NOIRHOMME, College mi­litaire royal de Saint-Jean. - The Metal Insulator Semiconductor (MIS) type of induced junction solar cell offer several advantages, namely enhanced blue re­sponse, low temperature fabrication processes, higher open circuit voltages and simple processing tech­nology. However these cells which depend on oxide charge are generally unstable. Progress towards con­structing an induced junction solar cell using alter­nate charged materials will be described. This cell is to be made by interfacing a transparent polymer elec- tret on a semiconductor substrate with a MIS inter­digitated rectifying contact on its front surface. The possibility of using Corona charged polymers in order to deplete or invert a semiconductor has been demon­strated using a test structure^. Experiments per­formed in order to cast polymer films on the grating cell will be described.

1-A. Filion and M.M. Perlman, Proceeding of the 16e*1 IEEE Photovoltaic Specialists Conference, San Diego, September 1982.*Supported by D N D , CRAÛ Grant No. 3610-628.

Determination of the Active Laver Temperature Near the Channel of CaAs MESFET's. L. BOURBONNAIS, 0. BER0L0, Communications Research Centre. Ottawa and E. FORTIN, Department of Physics, University of Ottawa, Ottawa, Ontario - A technique is proposed by which the self-heating in the channel of a GaAs field-effect tran­sistor can be determined from the temperature-dependent shift in the optical absorption edge. When the usual d.c. bias cond tions are applied to these transistors, the source-to-drain current causes thermal dissipation due to joule heating within the channel. The increase in channel temperature causes a shift in the optical band gap of the semiconductor. This shift can be obser­ved by measuring either the photovoltage at the gate or the photoconduction at the drain. Using standard spec­

50

troscopic techniques, it has been found that the appli­cation of the drain bias causes a shift in the optical absorption edge because of the joule self-heating. The electric-field dependent shift was found to be negligi­ble. An empirical expression was used to fit the expe­rimental data on five different transistors from four independent industrial sources. This result was then used to calculate the temperatures reached in the chan­nel of the transistor due to self-heating.

DE4 photoluminescence and Optical Absorption Studies of the Effects of Heat Treatment on Cuprous Oxide. C.K. TEH*and F.L, WEICHMAN, Dept, of Phys., U. of Alberta - The annihilation of defects in cuprous oxide has been observed from the photoluminescence and absorption measurements after the sample has been annealed twice with a lower temperature in the second annealing, at a reduced oxygen pressure. From the photoluminescence measurements, the density of these defects are found to decrease exponentially as a function of annealing time as manifested by a reduction in the luminescent intensity. The rate of reduction in intensity is also found to increase with annealing temperature. Since the defects responsible for the luminescence are ascribed to various forms of oxygen vacancies, we believe the decrease in luminescence is due to the precipitation of excess copper centers which are associated with the oxygen vacancies. The short-wave (720 nm) and medium-wave (820 nm) emis­sions, which are ascribed to different types of oxygen vacancies are found to have different activation energies of diffusion.

^Supported by NSERC.

D E 5 High Sensitivity Sub-Nanosecond PhotoluminescenceMeasurements in Semiconductors. T. Steiner and M.L.W. Thewalt, Simon Fraser University - We have assembled an apparatus for measuring photo luminescence decay tran­sients on a ns and ps time scale, while retaining the high sensitivity and dynamic range of photon counting. Synchronously pumped dye lasers provide excitation pulses of 10 - 30 ps width and average powers to 100 mW over the visible and near infrared regions, wi'th the possibi­lity of frequency doubling for ultraviolet excitation.The photoluminescence signal is detected by high infrared (1.2μ) region with quantum efficiencies to 20% and low dark counts (30Hz), enabling us to measure the decay characteristics of transitions with extremely low quantum efficiencies. Some initial applications of this system to measuring short photoluminescence life­time in semiconductors will be discussed.

Transient Photo Luminescence in In and Tl Doped Silicon. S.P. Watkins and M.L.W. Thewalt, Simon Fraser University - Unusual transient photo luminescence results are reported for the isoelectronic bound exciton system in In doped Si. These results provide further evidence for the existence of a new type of bound exciton defect, first exemplified by the recently discovered1 Si:X£ centre. Both of these centres are modelled in terms of an isoelectronic binding site which can exist in either of two non-equivalent config­urations, which are separated by an energy barrier of roughly 20 meV. These are the first reported obser­vations of structural reconfiguration in a bound exciton centre.

1 M.L.W. Thewalt, U.O. Ziemelis and R.R. Parsons, Phys.Rev. B 2 4 , 3655 (1981).

DE7 Electronic Structu re of Ac-row Impurities in Cesium.* G. KENNING and E. ZAREMBA, Queen's U . ,Kingston - Systematic experimental studies of the impur­ities Ag to Xe in cesium have revealed interesting trends in the residual resistivity, magnetic susceptibility and spin-flip scattering cross-section. The trends correlate qualitatively with the position of the atomic 5p level relative to the Fermi level of the host metal. We have performed self-consistent electronic structure calcula­tions for these impurities using the density functional theory within a local density approximation. The detailed scattering phase shift information ar.d electron density distributions allow one to calculate the measured quantities. The qualitative behaviour of the residual resistivity is reproduced however the calculations cannot explain the anomalies observed in those cases for which the impurity has a nearly half-filled p-shell. Some of the discrepancies between theory and experiment can be associated with the incorrect position of the 5p level as obtained in density functional calculations, however the single-particle description of the impurity electronic structure may also be inadequate.

*Supported by NSERC of Canada.

Quantum Oscillations in the Transport Co­efficients of Afl. R. FLETCHER, Queen's Universi t y , Kingston - Detailed measurements on the quant im oscillations in the transverse resistivity (both thermal and electrical) and the thermopower of A£ have been made at fields of up to ÔT in the liquid helium temperature range. The results show that, given the absolute amplitude and waveform of any one of the coefficients, the detailed behaviour of both of the others may be calculated with a precision of a few percent by a phenomenological theory1. The results provide an accurate verification of the well known Mott relation­ship relating thermopower S and resistivity p i.e.S - LeT(dJlnp/d8) , and also pose some interesting questions concerning the role of many body effects in the observed coefficients. Because the theory takes into account only diffusion effects in the thermopower, we conclude that phonon drag plays no appreciable role in the mechanism producing quantum oscillations in AH.

F l e tcher, R . , J. Low Temp. Phys., 43, 363 (l98l).

DE9 Edges and the Quantized Hall Effect. C.Kallin,* Harvard u.■ Cambridge MA - ihe quantization of the Hall conductivity oxy of a two-dimensional electron system in a magnetic field, when the Fermi level lies in an energy gap of extended states, is now well under­stood.1 However, in a finite system, this gap collapsesat the edges of the sample and special consideration must be given to the role of edge states. Edge effects have previously been studied only in the case where there is no resistive loss (o .=0).2 In this paper, edge effects are studied in tne presence of dissipa­tion and also of disorder. The possible role of edge states in actual experiments will also be discussed.

^.B. Laughlin, Phys. Rev. B23, 5632 (1981)."B.I. Halperin, Phys. Rev. B25, 2185 (1982).

* Supported in part by an NSERC Postgraduate Fellow­ship and NSF DMR 82-07431.

DE10 Effects of copper inclusions on the transient photoconductivity of cuprous o x i d e , C.C. TIN*and F.L. WEÏCHMAN, Department of Physics, The U. of Alberta - Transient photoconductivity measurements have been made on three types of cuprous oxide having different defect structures. Studies of the slow components of the photoconductivity decay signals have shown that the values of the trap levels together with the capture cross-sections for the different trapping centers were found to be different for the different types of samples. Preliminary results seem to indicate that the samples containing copper inclusions have smaller capture cross­sections than standard type of cuprous oxide and this difference could be due to the formation of internal Schottky barriers.

*Supported by NSERC.

D E 11 Transient Charge Technique Measurements inStrontium Titanate* D. Kéroack, Y. Lépine and J.L. Brebner, Département de Physique, Université de Mont­real - Electrical measurements using the transient charge technique (TCT) have been made on SrTi03 samples as pure as possible with temperature varying from 100K to 400K. The samples used were highly resistive (n = 10^ cm and p = 10^0 £L cm for T = 300K). An upperbound to the drift mobility has been found (.1 cm 2/v sec for T = 300K) and this mobility is activated at high temperature (activation energy .13eV). Estima­tej of other parameters (trapping and detrapping times are given). The high temperature behaviour (smalInac­tivated behaviour) is discussed in terms of small pol- aron hopping and (or) trap controlled mobility. This analysis is compared to that of Boyeaux et al.l in the case of BaTi03 .

1 J.P. Boyeaux and F.M. Michel Calendini, J. Phys. C12, a 545 (1979).

Supported by the Natural Sciences and Engineering Research Council of Canada and Le Ministère de l'Edu­cation du Québec (F.C.A.C.).

precise form of the structure factor. The present work describes explicit calculations of structure factors for crystalline metals using experimental phonon dis­persion data. The calculated resistivity change for both sodium and potassium is in good agreement with experiment. The calculations also reveal significant detail in the solid structure factor. The relevance of this detail to structural phase transitions in bcc and hep metals is described,

*Work supported by NSERC.

Also of Alcan International Ltd.

DE14 Le role des fluctuations quantiques 1-D dans les conducteurs quasi Ι- P .* C. BOURBONNAIS4· et L.G. CAR0n7 Département de physique, Université de Sherbrooke - Nous étudions l'effet des fluctuations quantiques à caractère unidimensionnel sur l'ordre à longue portée dans les conducteurs quasi-unidimensionnels. Nous utilisons à cette fin le groupe de renormalisation de Wilson sur une représentation intégrale fonctionnelle de chaînes métal­liques faiblement couplées.

* Financé par le CRSNG et le Ministère de l'éducation du Québec.

t Aussi au Laboratoire de physique des solides, Univer­sité de Paris-sud.

ROOM 139

MEDICAL AND BIOLOGICAL PH YSICS

DE12 Suoe rconductivity of Two-dimensional Mercury Compounds.* W. R. DATARS, K. MORGAN and"R.J. GILLESPIE McMaster University - Two new compounds Hg3 Ta F5 and H g3 Nb F5 have been synthesized. X-ray diffraction show that the mercury is in two-dimensional layers rather than in linear chains that occur in Η2^_ r As F^ but have not yet determined whether the mercury is commensurate with the host lattice. Superconductivity in samples of small crystals has been detected by ac susceptibility measurements and is very similar in both two-dimensional compounds. The critical temperature at zero field is 6.4 K and the critical field at 1.3 K is 0.25 T. The critical field - critical temperature relationship has also been determined. The results are compared with theories of two-dimensional and three­dimensional superconductivity.

* Research supported by Natural Sciences and Engineering Research Council of Canada.

DEI3 Hot Solid Structure and Electrical ResistivityA.M. ROSENFELD 1 and M.J. STOTT, Queen's U n i v .- Recently we have proposed a consistent approach to the calcula­tion of resistivity in liquid and crystalline metals near the melting point in terms of the respective structure factors In the absence of experimental structure factor data for hot solids a simple model was adopted to estimate the change of resistivity on melt­ing. Good agreement with experiment was obtained for a number of polyvalent simple metals but not for the alka­li metals for which the theory is most sensitive to the

DF1 Commercial Manufacture of Cyclotron Produced Radio iso topes'.' D. GRAHAM, R. ROBERTSON ancT'l . TREVENA. Atomic Energy of Canada Limited, 4004 Wesbrook Mall, Vancouver, B.C., V6T 2A3 - TRIUMF and AECL entered into an agreement in 1978 to collaborate in the production of cyclotron radioisotopes. At TRIUMF a facility for the irradiation of targets with 500 MeV protons was commissioned in 1980. Procedures for the production of high specific activity copper-67, germanium-68, strontium-82, cadmium-109 and xenon-127 have been developed and the products have been shipped worldwide. Using a CP-42 variable energy negative ion cyclotron supplied by the Cyclotron Corporation and operated by TRIUMF Applied Programme personnel, AECL can produce isotopes such as gallium-67, indium-111 and thallium-201 which are made by direct reactions and which have widespread application in nuclear medicine as diagnostic tools.

DF2 The Production of Positron Emitting Radionuclide on the CP-42 at TRIUMF*. T.J. RUTH, M.J. ADAM, W. GELBART, Y. H0MMA, S. JIVAN & B.D. PATE TRIUMF & Dept, of Pharmaceutical Sciences, University of B ritish Columbia.- The CP-42 is a commercial cyclotron built by the Cyclotron Corporation. It accelerates H“ ions and delivers 11-42 MeV protons down its vaiable energy beam line with beam currents up to 200pA Target designs will be discussed for the production of ^ F , ^ 0, ^ C and ^^Br with beam and target parameters for multi-millicurie quantities of these radionuclides. An entirely new method for the production of ^®F-F2 utilizing a new

52

ta rg e t bombarded by p ro ton s w i l l be d e s c r ib e d · Examples o f some o rg a n ic chem ica l re a c tio n s w i l l a lso be p re se n te d ·

*Supported by grants from NRC, NSERC and B.C. Science Council·

DF3 Low Temperature Magnetization Measurements of Seme Chrysotiles and Human Lung Tissue. D. HUTT, G. STROINK and R. A- DUNLAP, Dept, of Physics, Dalhousie University. - The magnetic properties of several Canad­ian chrysotiles and UICC standard reference samples of chrysotile have been measured at various temperatures between 4.2° K and 300° K. Samples of human lung tissue contaminated by asbestos were similarly studied. The susceptibilities measured at large fields (> .5 T) are due to the chrysotile. It shows a paramagnetic behav­iour at all temperatures measured. The hysteretic prop­erties of the sample are due to magnetite impurities in the form of small granules. The temperature dependence of these properties was observed and estimates were made of the magnetite particle size distribution based on the magnetite superparamagnetic threshold diameter which is temperature dependent. At 4.2° K the magnetite part­icles have no superparamagnetic fraction and estimates of the total amount of magnetite in each sample were made, based on the values of remanence and saturation moment observed at this temperature.

DF4RS

MULTIPHOTON ABSORPTION IN OPTICALLY PUMPED Rb°Ν'. S. HO. Dent, of Physics. Roval Roads Military College. Victoria, B.C. - The experiment consists of a circularly polarized Rb^S Dj light passing through a Rb8S absorption cell to reach a Si photocell which monitors the light in­tensity. Surrounding the Rb vapor cell is a solenoid energized by a sweeping function generator to provide r-f nhotons to the optically pumped Rb vapor. The pumping Di light and the axis of the solenoid are parrallel to the earth's magnetic field. If the rf field has a frequency corresponding to the Zeeman transition, the optically pumped Rb atoms will return to a random population of the ground state Zeeman sublevels causing a decrease in the intensity of the transmitted Di light. Thus, by sweeping the rf frequency slowly through the resonance, the point at which the minimum intensity of Di light occurs may be observed as an absorption line on a X-Y recorder. Multi­ple absorption lines are observed. The highest peak occurs at the correct resonance frequency, the next one at 1/2 of this frequency, and the nth peak appears at 1/n of the resonance frequency. These multiple absorption lines may be explained by multiple rf photon absorption of the optically pumped Rb atoms.

DF5 The Biomedical Program at TRIUMF. L. SKARSGARD,G. GOODMAN, B. PALCIC, G. LAM, D. CHAPLIN, B. DOUGLAS,C. LUDGATE, R. KORNELSEN and R. HARRISON, B . C ^ C a n c e r Research Centre and Cancer C o n t r o l Agency of B.C., Vancouver - Since the Spring of 1982, the patient treatment facility at TRIUMF has been equipped with a system which allows raster scanning with a negative pion beam. The depth of penetration of the pions is adjustable using a range shifter whose operation is coupled by computer control to a patient transport couch which scans in two dimensions at right angles to the beam. With this "spot scan" method it is possible to produce uniform dose regions of a variety of shapes and sizes.

The treatment planning method will be described with the resulting distribution for a typical patient with a pelvic tumour.

About a dozen p a t ie n ts w ith deep-seated tumours have been tre a te d . The response o f norm al t is s u e s agrees w e l l w ith th a t p re d ic te d from e a r l ie r b io ­lo g ic a l experim en ts .

ROOM 139

EDUCATION AND TRAINING

UG1 The University of B r itish Columbia Ph ysics Olympics, MICHAEL J . CROOKS, Dept, of Physics, University of B . C . - A day of contests and other events related to physics has been organized for high school stvdents by the Department of Maths and Science Education with the cooperation of the Physics Department and held annually at UBC for several years. Senior secondary schools throughout B.C. are invited to send teams of tive students and this year 255 students from 35 schools in many parts of the province are expected. The teams take part in seven events during the day with awardífor the winners of each event and a trophy for the team with the high score for the day. The program stimulates many students and their teachers by giving them an opportunity to apply their knowledge of physics outside the classroom. An outline of the organization of the program and descrip­tions of some of the events used will be presented. Pictures taken during this Spring's Olympics will be shown.

DG2 R & D Activity: Science and Technology Grants and Contracts 1976-83. E.J. FJARLIE, Royal Military College - An examination is presented of the grants and contracts awarded to the universities and ind j s try by the Federal government during the period January, 1976, to March, 1983. Graphs are drawn showing the expendi­tures in the current year dollars as well as In 1976 dollars. There are significant increases in expendi­tures since 1978. The activity taking place Ln terms of univers!ty/industry : numbers of contracts, numbers of dollars, Federal government department invalved, and numbers of person-years where available, is aLso noted. Publications of the Ministry of State for Science and Technology have been used to prepare the anal/sis.

DG3 Stopping Power of Silver for 252Cf FissionFragments■* D. DESMARAIS, University of Alberta,J.L. DUGGAN, North Texas State University, and H.L. ADAIR, Oak Ridge National Laboratory. - The purpose of the pre­sent paper is to describe a procedure which could be used by undergraduate students in physics to measure the stop­ping power of silver for 252Cf fission fragments of various energies. The experimental value for the stop­ping power is obtained from the measured energy loss of the fission, fragments for five different thicknesses of silver absorber. The results are favorably compared to calculations making use of semiempirical theoretical formulae developed by Lindhard and revised by Millier.The theory is of such a form that an undergraduate student in physics can easily do the calculations.

DG4 Alpha particle induced inner-shell ionization measurements for the undergraduate laboratory.* D. DESMARAIS, University of Alberta, and J.L. DUGGAN, North Texas State University. - The interaction of alpha particles with low atomic number elements has been studied in an attempt to determine the inner-shell ionization cross section. These cross sections were determined by measuring the characteristic x rays that were produced when a thin aluminum target was bombarded by alpha particles from a 48 MBq 21+ltCm alpha source.The x rays were detected with a Si(Li) x-ray detector whose resolution was 190 eV at 5.9 keV. The efficiency of the detector was determined from standard radioactive sources. The energies of the alpha particles were varied by placing thin Mylar absorbers between the alpha source and the target. The results are favorably compared to a current ionization theory given in such a form that an undergraduate physics major can do the calculations.This experiment is intended as an undergraduate labora­tory experiment in the atomic or nuclear area.

K inetic Theory of the Underdense Region in Laser Created Plasmas. W. ROZMUS, Y. AL-SHIRAIDA, A.A. OFFENBERGER, Dept, of Elect. Eng., Univ. of Alberta - A theory is presented for laser induced processes in underdense plasma (0.3 < n /n < 0.9). Low frequency electrostatic instabilities have been analyzed and thresholds are found to be relatively low(0.05 < V /V <2). Growth rates and saturation , . osc ttje ,mechanisms are discussed. The instabilities can increase absorption, account for high level signals in Thomson scattering experiments and potentially inhibit stimulated Brillouin scattering. For stable plasmas, on the other hand, high levels of fluctuations are found due to Cerenkov emission by particles for pump strength below threshold. A rigorous kinetic theory is derived for such systems. Calculation of the form factor S(k) and absorption coefficient show good agreement with experiment. It is shown that, for a wide range of parameters, enhanced levels of fluctua­tions due to particle discreteness may account for increased collisionality in laser created plasmas (anomalous absorption, thermal transport inhibition) and affect stimulated Brillouin scattering.

ROOM 128

PLASMA P H YSIC S

DHl Ion Trapping and Heating as a Limiting Mechanism for Stimu lated Brillouin Scattering. R. GILES andA.A. OFFENBERGER, University of Alberta - The satura­tion of stimulated Brillouin backscatter in a C0^ laser- plasma interaction experiment is explained through ion trapping and heating. The elevated ion temperatures to 0(ZTe ) as inferred from backscatter reflectivity and spectral measurements are consistent with ion heat­ing leading to convective instability. Further evi­dence for ion trapping and heating came from the insta­bility risetime as measured through backscattered light and ruby laser Thomson scattering off the Brillouin driven ion mode. Ion acoustic wave energy absorption due to ion heating accounts for the long (> 500 ps) riset ime.

Ion_ turbulence in a C0_ Laser Heated Plasma. Y.S. AL-SHIRAIDA, A.A. OFFENBERGER, Dept, of Elect. Eng., Univ. of Alberta, and A.NG, Physics Dept., Univ. ofB.C. - Ion turbulence generated in a CO^ laser heated plasma has been studied using ruby laser Thomson scat­tering. The experiment was motivated by previous evi­dence for anomalous absorption of the C0_ laser radia­tion. As a consequence, the first detailed measurement of the ion fluctuation spectrum, S(k), induced in the plane of the laser electric field by a high intensity focused C0_ laser beam has been made and is reported here. High speed streak measurements of the Thomson scattered light indicate very short duration (^ 1 ns) and fast rise-time (*v 50 ps) features in the enhanced ion fluctuations. A theoretical model for the observed features is discussed in a companion paper .

W. Rozmus, Y. Al-Shiraida and A.A. Offenberger,Kinetic Theory of the Underdense Region in Laser Created Plasmas (presented this conference).

1

DH4 Stimulated Raman Scattering Simulation.A. ALFHEIM, A.J. BARNARD and E. HIOB Dept, of Physics, UBC, Vancouver, B.C. - Forward and backward stimulated Raman scattering has been studied in D by either following particles (representing electrons) or by solving the Vlasov equation, both in the presence of a laserfield. With a uniform plasma and periodic boundary conditions we find that the effective damping of plasma waves is greatly increased at higher irradiances, as energetic electrons are trapped in the waves; these electrons must be treated relativistically. For hot plasmas, forward scattering dominates and produces faster electrons. Our procedure is being extended to deal with a laser beam propagating into a density ramp.

DH5 B a c k s c a t t e r O b s e r v a t i o n s in a C O ; L a ser Gas Jet E x p e r i m e n t . * J . E . B E R N A R D , J. M E Y E R , H. H O U T M A N , δ . Ill L K 0 , G. M c I N T O S M , a n d R. P 0 P I L , U B C A h i g h i n t e n s i t y ( * 5 *10* ^ / c m 2 ) s h o r t p u l s e T ^ n s ) C O 2 l a s e r b e a m has b e e n f o c u s s e d o n t o a l a m i n a r n i t r o g e n gas j e t t a r g e t to p r o d u c e a s u b c r i t i c a l p l a s m a w i t h an e l e c t r o n t e m p e r a t u r e of the o r d e r o f 1 KeV. O b s e r v a t i o n s o f the b a c k s c a t t e r e d l i g h t at ω 0 a n d 3/ 2ω υ b a v e b e e n m a d e . T h e b a c k s c a t t e r at ~ w 0 , a t t r i b u t e d to s t i m u l a t e d B r i l l o u i n s c a t t e r i n g (SBS) has b e e n t e m p o r a l l y r e s o l v e d o n a s u b - n a n o s e c o n d t ime s c a l e a n d s p e c t r a l l y r e s o l v e d u s i n g a m o n o ­c h r o m a t o r and i m a g e d i s s e c t o r . At the h i g h e r i n t e n s i t i e s the S B S o f t e n a p p e a r e d t e m p o r a l l y as t w o p u l s e s w i t h a p e a k r e f l e c t i v i t y of l ess t h a n 10% i n d i c a t i n g s o m e f o r m o f s a t u r a t i o n .T h e s p e c t r a l o b s e r v a t i o n s i n d i c a t e a p l a s m a b l o w o f f . T h e t h r e s h o l d and r e f l e c t i v i t y o f the s i g n a l at V 2u 0 a r e w e l l c o r r e l a t e d w i t h the p r o d u c t i o n of f a s t e l e c t r o n s a t t r i b u t e d to t w o - p l a s m o n d e c a y .

* T h i s w o r k s u p p o r t e d b y a g r a n t f r o m N S E R C .

54

DH6 Energy Balance in a L aser Gas-Jet Fxperimént.*R.Popil,J .Meyer,J .E.Bernard,B.Hilko,H.Houtman,G .McIntosh University of British Columbia - The results of a CO^ -

laser laminar gas jet expriment will be reported and discussed in terms or an energy inventory. Laser intensi­ties approaching 10*' W/cm focused by f/5 optics onto a 1.3 mm thick supersonic gas jet produce a plasma emitting visible and x-ray radiation which are used to determine the absorbed energy and electron temperature. Streak photographs of the visible emission and of the shadow of the plasma are used with blast wave analysis to determine the absorbed energy. X-ray meaurements of the plasma emission through various absorbers yield the electron temperature and subsequently the thermal energy of the plasma. These results will be correlated and substantiated by measurements of the absorbed energy using an Ulbricht integrating sphere, the electron temperature as inferred from the observed red-shift in the Stimulated Brillouin backscatter and by the results from a one-dimensional hydrodynamic computer code simulation of the laser-plasma interaction.

* Supported by N .S .E .R .C ., Canada.

DH7 Energetic Electron Distribution in C02 Laser- Produced Plasmas. ÜTD. Enright and N.h. tfurne11, _ National Research Council of Canada - Measurement of the x-ray spectrum in the range 100-300 keV from CO2 laser produced plasmas have confirmed the existence of an energetic electron component that may be characterized by a "temperature" of M>0 keV at an incident intensity of n>2 x 1 0 ^ Wcm" The integrated intensity of this x-ray spectrum is comparable to what has been observed in a 20 keV component in the x-ray region between 2 and 70 keV. It is estimated that a Maxwellian distribution of electrons containing ^>3% of the incident laser energy must be incident on the target to account for the observed spectrum. This fraction may be strongly dependent on incident laser intensity, as the flux of ^200 keV x-rays decrease^ by more than an order of magnitude for I ^ 5 x 10 Wcm ^ . It is therefore not surprising that this energetic electron component will^ dominate the energy balance at intensities > 10'1"' Wcm as has been reported by researchers at Los Alamos National Laboratories.

DH8 Feedback Effects in Stimulated Brillouin Scat­ter. G.R. Mitdhél. I.W. jonnston, h . pépin, tNKb-tner- qTëT Varennes, Québec - A feedback mechanism is_studied wherein~Brinouin scatter from 1 aser-produced plasmas is partially reflected back inward from a subcritical den­sity shelf, to be rescattered, and so on. Sufficient feedback may turn a convective instability into one that absolutely grows in time, at least in a homogeneous plasma. Temporal growth may be accompanied by slow time oscillations of the instability level, due to round-trip phase effects. In inhomogeneous plasmas, a 10% density steepening at quarter-critical, for example, can signi­ficantly increase Brillouin scatter in the linear regi­me.

DH9 CO^ collective laser scattering on movingdensity perturbations in a plasma.* D.C. SCHRAM,H.W.H. VAN ANDEL, G. LECLAIR, and P. BRODEUR, Université de Montreal - C 02 laser scattering from plasma density perturbations which are not wave­like in nature moving through the beam is calculated for various geometries and scale-lengths. Exact expressions are found for the heterodyne detector currents as a function of time, and for the corres­ponding frequency spectra. In particular, the cases of small-scale rotating density perturbations

in cylindrical plasmas and off axis rotation of the entire plasma column are analyzed in detail. By way of illustration, the theoretical results are compared with some measure scattering spectra from a magnetized arc.

* Research supported by NSERC.

DH10 Intensity and Wavelength Scaling of Mass Abla­tion Rate and Ablation Pressure in Planar Targe t s ♦ A. NG,J. KWAN, D. PASINI and P. CELLIERS, Dept, of Physics,UBC, Vancouver. B.C. - Laser-driven ablations in planar aluminum targets have been studied using 0.53 and 0.355 pm laser light. Absorbed laser intensity (Φ3 ],8) was < 1013 w/cm2 and the pulse length was 2 nsec (FWHM).The ablative flow of ions from target front side was monitored by arrays of Faraday cups and calorimeters.The mass ablation rate, m, was found to vary as

·; , and for 0.53 and 0.355 ym respectively. Thisabs abs

intensity scaling is consistent with absorption by inverse Bremsstrahlung at and below critical densities as well as good thermal transport in the overdense region of the target. For the range of intensities used, m scaled as

—1 88T ‘ The ablation pressure perpendicular to targetr , , „ . 0.75 , 0.72surface n , was found to scale as v . and , forabs abs

0.53 and 0.355 pm respectively. However, P_, scaled as-0.14 *

λ T * only. On the other hand, the total momentum-0 ~ 8

deposited on target was found to vary as λ. * " This indicated that 2-dimensional effects may be important.

Diffusion CO? à petit angle sur une colonne de plasma à densité électronique elevee. J.-L. IACHAMBRE et R. DECCfoTE, Institut de recherche d 1Hydro-'Québec - Nous décrivons une e x p é r i e n c e 3 e diffusion-laser-CC)2 à émission continue avec détection hcmodyne sur une colon­ne de plasma stabilisée (5 x 1021 m - 3 , 6 ev) dont le but est de mesurer les spectres en fréquence et en vecteur d'onde S(k, ω) associés aux fluctuations électrostati­ques spontanées. Durant la phase stationnaire de la dé­charge, les fluctuations dépassent le niveau thermique de plusieurs ordres de grandeur avec une dépendance spectrale de la forme k -i* et ω-^. Ces fluctuations sont isotropes dans un plan transversal au chanp magnétique avec S(k„ , ui) << S(ki( ω) .

Nous utiliserons la diffusion à petit angle pour déterminer l'ensemble des conditions expérimentales appropriées pour la mesure de la tenpérature ionique à l'aide d'une source pulsée. Nous donnerons les résul­tats de l'analyse du système, décrirons le montage expé­rimental et présenterons 1 'état des travaux sur cette expérience de diffusion cohérente pulsée à 5° avant sur la colonne de plasma avec une impulsion CC^-TEA de 0.5 M W sur 2 ys en durée.

DH12 Transport d'énergie par les électrons suprather- miques dans l'interaction laser tu, cibles-solιdes. j .l . Kierrer, h . Hepin, j .r . natte, v. Lavigne, iNRS- Energie, Université du Québec, Varennes, R. Decoste, institut de kecherche Hydro ljueDec, varennes, F. Amira- noff, Ecole Polytechnique, Pari s,'~F rance - Le transport d'énergie par les electrons chauds générés au cours de l'interaction d'un laser C02 et d'une cible solide est étudié à partir du rayonnement X continu (10-70 KeV) et du rayonnement Ka issus de cibles multicouches. Les profils et la géométrie de déposition d'énergie sont obtenus à diverses profondeurs dans la cible. On obser­ve qu'environ 10% de l'énergie laser incidente E|_ est déposé dans le solide par des électrons ayant des éner­gies supérieures à 10 KeV; à bas flux ces électrons sont

tous incidents suivant la normale à la cible; à haut flux seul un petit nombre d'électrons est incident sui­vant la normale à la cible dans une zone de petit diamè­tre (< 2 mm) n'y déposant que 1% EL; les électrons les plus énergétiques, incidents de façon semi isotrope, déposent le reste de l'énergie (9% Ei ) loin de la tache focale sur une très grande surface. Ces résultats traduisent l'apparition de champs magnétiques intenses dans le plasma. La physique du transport est discutée quantitativement.

DH13 Instabilités paramétriques dans un plasma inho­mogéné - ü. Picard et I .w. Johnston, iNkS-tnergie, va- rennes, Québec - Nous étudions les instabi11tes paramé­triques de trois ondes couplées dans un plasma unidimen­sionnel. Nous considérons le cas où les deux ondes filles ont des vitesses de groupe opposées. Il était déjà connu que pour une amplitude de couplage constante et un gradient de mésadaptation constant (dzk^/dx=cte) aucune instabilité absolue n'est possible. Nous mon­trons que ce cas est exceptionnel et qu'en général une instabilité absolue est possible dans un plasma inhomo­gène, pourvu que l'intensité de l'onde pompe soit suffi­sante. Nous présentons un critère simple pour définir le seuil de cette instabilité.

DH14 Etude de la distribution angulaire de rayonne­ment diffuse par un plasma produit par laser CO,, h. Martin, J. saDDagh, t>. rntcnel, H. Pepin, TTff. Johns­ton, INRS-Energie, Université du Québec, Varennes, Qué­bec - Les mesures de l'energie diffusée a ω. et 2ω0 lu)0=fréquence laser) ainsi que la distribution spec­trale en fonction de 1 'angle de diffusion et de la pola­risation du laser incident ont permis de définir plu­sieurs mécanismes de couplage paramétrique. Le rayonne­ment diffusé dans le plan spëculaire à la fréquence laser est décalé vers le bleu et présente une distribu­tion en énergie à deux maximum; le premier à l'angle spéculaire, le second aux environs de 45° de la normale à la cible. Le décalage spectral est consistant avec celui obtenu par un couplage paramétrique de l'onde laser avec une onde ionique en tenant compte de l'expan­sion du plasma. La distribution angulaire du rayonne­ment diffusé à 2ω0 comporte les mêmes maximum. Le décalage spectral au spëculaire est rouge et possible­ment causé par le couplage de deux plasmons qui ont été produits par le procédé de désintégration paramétrique. Le décalage spectral pour le maximum autour de 45° est bleu et possiblement causé par le couplage de deux plas­mons produits par 1 'absorption résonnante.

DH15Raman Puise Production and Amplification in Methane Using a KrF Laser Pump*. R. Fedosejevs, D.C.u. McKen,C. Domier, I.V. Tomov* and A.A. Offenberger, Dept, of Electrical Engineering, U, of Alberta - The production and amplification of first Stokes Raman pulses in methane gas using a 3GHz linewidth KrF laser pump pulse has been investigated experimentally. The spatial, temporal and spectral structure of the Raman light generated by focus­ing a KrF pump pulse into a 3.3 m long methane cell was studied for a variety of gas pressures and focal lengths, in order to determine the best method of producing an initial first Stokes pulse. Subsequently, the pulse has been amplified and compressed in a second methane cell pumped by a second narrow-1inewidth KrF laser pulse.The limitations on conversion efficiency due to genera­tion of second Stokes and the enhancement of the second Stokes generation due to temporal and spatial structure

in the Raman beam are presently under investigation. Detailed experimental results will be presented together with conclusions on optimizing the design of a practical Raman pulse amplifier/compressor scheme.

♦Supported by the A1berta/Canada Energy Resources Research Fund.+Permanent address, Sofia University, Bulgaria.

LASER BEAM COMPRESSION AND CLEANING

USING RAMAN BACKSCATTERING*

R. Marchand, C.E. Capjack and C.R. James University of Alberta

Results from a two-dimensional simulation of a KrF laser pulse compression are presented. The temporal compression is achieved by sending two counterpropa- gating laser beams in a cylindrical plasma cell. Because of the parametric coupling between the two b e ams f the shorter pulse (the Stokes) can absorb energy from the longer one (the pump) to yield an energy conversion efficiency of order 50%. Our results indicate that radially non-Gaussian pumps can be compressed into Stokes pulses with nearly Gaussian radial profiles. This is of interest in view of the potential use of energetic KrF pulses as fusion drivers.

* Supported by the National Science and Engineering Research Council.

DH17 A Thick-Sheath Electrostatic Probe.*C.S. MACLATCHY, Acadia University, Wolfville, N.S. - A unique technique for measuring the sheath thickness of a thick-sheath electrostatic probe in a moving, atmosphe­ric pressure flame has been devised. The method invol­ves the comparison of two probe currents— one due to a small test probe, the other due to a larger standard probe. The probes are swept simultaneously through the flame. In the analysis, the only assumption is that the probes are operated in the thick-sheath regime; there are no assumptions concerning the nature of the flame. The measurements agree favorably with the thick-sheath theory of Clements and Smy1. In addition, the ion den­sity can be computed. In certain types of flames where the precise nature of the flame may not be known, this measuring technique may be the only means of measuring the electron density.

'Clements, R.M. and Smy, P.R., J. Appl. Phys. 40, 4553 (1969).

♦Supported by the Natural Sciences and Engineering Research Council of Canada.

56

DH18 Eigenmode Equa tion for Electrostatic Drift Waves In Tokafflaks*. A. HIKUSK. Unlv. ol Sask. - In analyzing electrostatic drift waves in a tokainak, the following mode differential equation Is usually employed:

k 2)Πι

+ f TqRp { (m - nq) 1 3Θ3 2

bl -

ω + *1{1 + Z(t )}

c

e (cos9 - isinÖ 9 .— 3Ϊ)]

(r, Θ) = 0

where 4>m (r,0) is the ra-th Fourier harmonic amplitude of the potential, m(n) is the poloidal (toroidal) mode number, e=r/R and kTn=m/r. Other notation is standard.It is shown that the last operator should be replaced by

to* T ,

ω(ω + ω ^ )(COS0 - i sin6 9 y

V. 9r'e

which vanishes in the limit of T^>>T^. That is, for T e» T i , electrostatic drift waves are little affected by toroidicity and remain stable. The stability of the case T e£Ti is currently under study.

*Sponsored by NSERC.

DH19 Stochastic MHD Waves. J.TEICHMANN, Unlv. of Mon­treal, Phys. D e p t .- Magnetohydrodynamic waves in plas­mas penetrated by stochastic fluctuations of the macro­scopic parameters such as density, magnetic field and temperature are studied. The selfconsistent theory of Alfvén and magnetoacoustic waves is elaborated on the basis of different stochastic models.

It is shown that the spectrum of eigenmodes is strongly influenced by statistics of the fluctuations. The analysis gives conditions for new stochastic in­stabilities .

DH22 Measurement of Central Ion Temperature and Cen­tral Neutral Atom Üënsity on the WEGA tokárnak using a fast Chopped Neutral Hearn. Ü.C. GREGORY, iNRE-tnergle, Varennes, Quebec, W.R. HESS and C. GORMEZ ANÜ7~Lentre d'études nucTeáires de Grenoble,^France - We describe an active neutrârbeam diagnostic mounted on the WEGA-Toka- mak and used in conjunction with a single channel neu­tral particle energy analyser. The central ion tempera­ture was measured to be 270 eV before lower hybrid heat­ing and 340 eV during 178 kW of heating. In addition, the central neutral atom density was deduced from expe­rimental results to be 1.3 x 10ll+nr3 (within a factor of 2) using this active measurement technique. The relati­ve efficiency of the charge exchange analyser measured using the active beam is in good agreement wi :h indepen­dent calibration.

DH23 T hermal Wall Loading in a Vortex S tab LI ízed Arc.* J.B. PEARSON and F.L. CURZON, University of British Columbia - Studies have been carried out on the combined conductive and convective transport of heat to the wall in a vortex stabilized argon arc. The argon pressure is 5 Atm. and the arc length is 10 cm. In these investigations the arc was run at a current of 220 A DC and a total power of 18 kW. The thermal loading of the wall was measured as a function of axial position along the arc. This was done by using a short section of wall which was independently water cooled. Axial profiles were obtained by shifting the position of the arc relative to this short section. It has been found that the wall loading increases very rapidly immediately adjacent to the upstream electrode. Throughout the length of the arc the loading has been found to be fairly uniform. The results will be discussed with reference to possible models.

*Supported by the B.C. Science Council and NSERC, Canada.

DH20 Production d'un Plasma de Grand Volume.M.CHAKER,V .GLAUDE e t J .TEICHMANN, Univ. de Montreal, Dep t . de Phys. - Nous présentons une nouvelle machine linéaire UML-3 dans laquelle est produite une colonne de plasma de grand volume à partir d'une décharge à cathode chau­de à chauffage indirect. Le plasma diffuse dans un champ magnétique de 300 G, sur une longueur de 2m. Pour une pression de base de 3x10“^ Torr, on obtient une colonne de 16 cm de diamètre. Les diagnostics par sondes de Lang­muir, par l'étude de la propagation d'ondes ionosonores et ondes de Bernstein, concordent pour indiquer une den­sité et une température électronique de 2x 10^ cm“3 et 2.5 eV.

Cette colonne est utilisée pour l'étude de l'in­teraction fortement non-linéaire de micro-ondes (longu­eur d'onde de 3 cm) avec un plasma dont nous discute­rons quelques aspects.

DH21 Energy Confinement Usine Reverse Temperature Gradients. A. MILNE and B. AHLB0RN, Dept. of Physics, U.B.C., Vancouver - Magnetic confinement in a linear system allows particles and energy to escape from the ends. The energy end losses will be reduced if the temperature gradient in axial direction is inverted. We demonstrate this concept by creating a reversed axial temperature gradient in a Z pinch with the help of a shock wave. The Z pinch has electrodes with a hole on axis through which a shock wave can travel outwards during the compression phase of the pinch. To show the principle of energy confinement, the temperature is measured (spectroscopically) at the center of the pinch as function of time. This temperature is then compared with a similar experi­ment with solid electrodes where no axial shock is developed.

DH24 Energy States of Turbulent Flow. B. AHLB0RN and S. L0EWEN. Dept, of Physics. U.B.C. Vancouver - We describe the eddies that arise in turbulent~flow as a form of exicted state of the fluid flow. For eddies with simplified properties (called vortons) the interactions with the flow can be characterized by induced transition probabilities. The inter­action of the vortons with the fluid can be described by spontaneous transition probabilities. The boundary conditions of the flow restrict the available energy states. The population rate equations for these energy states are sufficient to determine the turbulent energy spectrum. Four cases of detailed balancing of rate equations are describ­ed. These make it possible to predict the onset of turbulence in wakes and boundary layers, the frequen­cy range of the turbulent energy spectrum and the velocity distribution in turbulent boundary layers. The results are in reasonable agreement with experi­mental observations.

DH25 Eddy Size Spectra in Turbulent Flown.S . L0EWEN and B . AHLBORN, Dept 7 of Physics, IJ. B . C . , Vancouver - A turbulent flow can be described as a superposition of a laminar flow and coherent rotating fluid elements (eddies), which may be characterized by an energy-eddy size spectrum.

Standard fluctuation measurements with hot wire anemometers yield a velocity fluctuation- frequency spectrum, which contains information about the eddy size spectrum only in implicit form. This paper describes how the eddy size spectrum is related to the fluctuation-frequency spectrum. We also examine methods to obtain the eddy size energy spectra for a given flow situations.

ROOM 129

PARTICLE P H YSIC S

DJI Quantum Fluctuât Ions In the Bag and Nucleon Observables. O.V. MAXWELL* & V.VENTO**, CEN de Saclay, Unlversidad de Valencia & TRIUMF. - A time-dependent, perturbative formalism is developed to describe the effect of gluon-induced quantum fluctuations of the quark fields inside a static, spherically symmetric hadronic bag on physical observables. Included are all second order (in gQcc) 2-body gluon exchange diagrams and 1-body vertex correction diagrams. The intermediate state sums are carried out over complete sets of quark and gluon bag states, which leads to logarithmic UV divergences in the 1-body terms. Regularization is accomplished by introduction of a cut-off, after which a finite renormalization based on the Ward identity and the SU(2) x SU(2) symmetry of the underlying QCD lagrangian is performed. The numerical results appear to justify such a perturbative approach for axial current observables but lead to anomalously large corrections to nucleon magnetic movements.

*TRIUMF**Universidad de Valencia

Constant Self-Dual Abelian Gauge Fields and Fermions in SU(2) Gauge Theory. D. KAY, R. PARTHASAR- ΛΤΗΥ and K.S. VISWANATHAN, Physics D e pt., Simon Fraser Univ. - Fermion one-loop corrections to the effective action In a self-dual abelian background field are calculated for an SU(2) gauge theory. It is found that these corrections tend to destabilize the vacuum. By minimizing the energy density and using the results of the charmonium decays, we obtain a lower bound for the mass of the charm quark as > 1.2GeV in agreement with experiments' *'

1. J.J. Aubert et.al Phys. Rev. Lett. 33, 1404 (1974), J E. Augustin et.al., ibid. 33, 1406 (1974),C. Bacci et.al , ibid. 33, 1408 (1974) and G.S. Abrams et.al., ibid. 33, 1453 (1974).

DJ3 Kaon Scattering and the Cloudy Bag Model.*E.A.VEIT** 4 B.K. JENNINGS, TRIUMF■ - Recently attempts1 have been made to describe kaon nucleon scattering using a chiral SU(3) XSU(3) cloudy bag model. In the usual cloudy bag model^ the meson couples to the baryon bag at the surface. There Is however, a varient of this model^ where the meson couples through out the volume. The pion nucleon bag coupling constant and form factor Is the same In both cases. However, we show in the present work that this is not true for kaon nucleon scattering where the two varients give rather different results. Results are presented and compared with experiment.

^R.C. Barrett, A.S. Rosenthal, A.W. Thomas and E.A. Veit work In progress.^A-W. Thomas (submitted advances In Nuclear Physics) TRIUMF preprint TRI-PP-82-29.*Supported by CNPq and NSERC.**Universidade Federal Do Rio Grande Do Sul, LUIZ ENGLERT, S/N - Porto Alegre - 90000, BRASIL

DJ4 Effective Potential in Supersymmetric Theories.G. F0GLEMAN, TRIUMF, K.S. VISWANATHAN, Simon Fraser Univ. - Effective potential for the supersymmetric chiral models i« explicitly computed to the two-loop approximation. The method relies on off-shell supersymmetric formulation In that the auxiliary fields are not eliminated1. Extensions to 0(N) symmetric chiral fields and to supersymmetric gauge theories will be presented.

Robert D.C. Miller preprint TH. 3475 CERN (1982).

DJ5 Measurement of the Induced Pseudoscalar Coupling Constant In Weak Semi-Leptonic Interactions. C.J. VIRTUE, K.A. ANI0L, M.D. H A S I N Ö F F ~ eT. HORVATH,H. R0SER, Dept, of Physics, U. of British Columbia, B.C. ROBERTSON, Dept- of Physics, Queen's U. - A survey Is made of observables in weak semï-leptonic processes to determine their sensitivity to the value of the induced pseudoscalar coupling constant, G p - A discussion and comparison of the various experimental techniques used to measure G and of the experimental results obtained to date1 is presented. The experimental techniques considered include: muon capture; recoil polarization; and gamma-neutrino angular correlation. An experiment currently in progress at TRIUMF to measure G0 through radiative muon capture Is described and preliminary results from a June 1983 run will be presented if available.

DJ6 The Muonium Lamb Shift Experiment. C-A- FRY, R.F. KIEFL, J.B. WARREN, UBC, G .A. LUDGATE, C.J. ORAM, P.W. SCHM0R, TRIUMF, G.M. MARSHALL, A. OLIN, U of Victoria.- An experiment is described to measure the 2 S L/2 "2P V 2 energy difference (Lamb shift) in the muonium ( y+ e“ ) atom. Muonium, whose ‘’nucleus'' Is a positive muon, Is purely leptonic so that finite nuclear size effect need not be Included In QED calculations of atomic level shifts. An Intense low energy muon source at TRIUMF Is producing the muonium atomic beam necessary for the first radio-frequency measurement of the Lamb shift. Methods for dealing with the special problems of backgrounds are emphasized and recent results are discussed.

DJ7 Spin-Spin Correlations in the Reaction -»· ρηττ+ at Intermediate Energ ies^* R. L. SHY PIT, C.E. WALTHAM, D.A. AXEN, F. ENTEZAMI, U. of British Columbia, M. C0MYN, D. HEALEY, G-A. LUDGATE, G.E.WAIT, TRIUMF, D.V. BUGG, J . A . EDGINGT0N, N.R. STEVENSON, Queen Mary College, London. - Spin-spin correlation parameters ^LL* ^SL« ^ss I A^jg and spin asymmetries Ag and At have been measured for the reaction

+ ρηττ· at Incident beam energies of 510, 465 and 420 MeV using the polarized beam and target available at TRIUMF. All three final state particles were detected. Charged particle tracks were recorded In one forward and two lateral MWPC arrays subtending ± 23° and ± 12° In the scattering plane. Neutron hits were recorded In an array of position sensitive NE110 Scinti­llation bars. Background subtractions were made using dummy carbon target data and were order 10%. Results agree well with predictions of the relativistic, unitary, one-pion-exchange Isobar model of Dubach et. a l 1.

ÍJ. Dubach, W.M. Kloet & R.R. Silbar, J. Phys. G 8, 475(1982).*Work supported In part by NSERC, Canada.

58

Standard SU(2)XU(1) Neutral Currents with Two L ight Neutral Gauee Bosons. Mark Singer and K.S. Viswanathan, P h y s . D ept., Simon Fraser Un i v . - A simple SU(3)XU(1) electroweak model, in which there is one new neutral current parameter R, is shown to give the standard muon neutrino and elec­tron neutral current predictions for all values of R. The model also gives muon neutral current predictions that are different from the standarcjl model, but still are consistent with experiment . For R of the order 1, one of the two light neu­tral gauge bosons is less massive than the charged one that mediates beta decay. This charged gauge boson has the same mass and inter­actions as the one in the standard model, and it is consistent with the particle reported at CERN.

A. Argento et al., Phys.Lett. 120B,245 (1983)

DJ9 The Differential Cross Section for Proton-Proton Elastic Scattering at 90ucm between ^00 and 500 MeV. D. OTTEWELL AND P.L. WALDEN, TRIUMF, E.G. AULD, G. GILES, G. JONES, G.J. LOLOS, B.J. MCPARLAND & W. ZIEGLER, Dept. o_f Physics., U BC, W. FALK, Dept, of Physics., U of Manitoba. - The absolute differential cross section for proton­proton elastic scattering has been measured t 90° c.m. for 300, 350, 400, 450 and 500 MeV. The statistical uncertainty of the measurements is 0.5% with an additional systematic normalization uncertainty of 1.5%. These results define the cross section and its energy dependence to a precision not previously available.

DJ10 The Analyzing Power o f the ftp ·» TT~*~d reaction at 375, 450, and 500 MeV Incident Proton Energies.* G.L. GILES, E.G. AULD,“ (Π JONES, G .jT”LOLOS", B.J. MCPARLAND & W. ZIEGLER, Dept, of Physics., UBC, D. OTTEWELL & P.L. WALDEN, TRIUMF, W.R. FALK, Dept, of P hysics., U of Manitoba. - The analysing power, A ^ Q i of the ftp ” iT d reaction was measured to a statistical precision of better than ±.01 at incident proton beam energies of 375, 450 and 500 MeV, for center of mass angles from 20° to 150°. The polarization-dependent differential cross-sections were fit by associated Legendre functions (using published data for the shapes of the unpolarized differential cross-sections). The energy dependence of the resulting b ^ - co­efficients were compared with existing data and theoretical expectations.

*Work supported in part by NSERC, Canada.

DJ11 The ftp-»pnn~t~ Reaction of 400 and 450 M eV*.W.R. FALK, Dept, of Physics., U of Manitoba, E.G. AULD,G.GILES, G. JONES, G.J. LOLOS, W. ZIEGLER, Dept, of Physics, UBC, P.W. WALDEN, TRIUMF. - A single armspectrometer measurement of the cross section and analyzing power of the ftp-*pnir+ reaction have been performed at 400 and 450 MeV incident proton energy. Measurements were made in the angular range of 46° to 90° (LAB), spanning a pion energy range of 10 to 30 MeV from threshold. Calibration of the 65 cm Browne-Buechner spectrometer, "Resolution" was carried our using tt+ from the pp-*dTT+ reaction. Coincidence measurements between the it and the d were made to investigate line shape and multiple scattering effects. Measurements were alternately made of C H2 and 12C targets, and the carbon background π events and π'ε from the pp-*dTi+ reaction were subtracted. The trend of the measured analyzing power follows that of the ρρ+ττ+d reaction. The cross section data will be compared to phase space calculations incorporating final state interaction effects.

*Supported by NSERC, Canada.

DJ12 Search for Muon-Electron Conversion wi:h the TRIUMF TPC7 M. LEITCH, D.A. BRYMAN, I. NAV0N, T. NUMA0, P. SCHLATTER, U. Victoria & TRIUMF, G. AZUEL03, P. DEPOMMIER, R. P0UTISS0U, U. de Montreal, A.L. CARTER, D. KESSLER, Carleton U., M. BLECHER, K. G0T0W, V?I & SU,M.S. DIXIT, C.K. HARGROVE, H. MES, NRC, R.A. BURNHAM, M. HASIN0FF, J.M. P0UTISS0U, UBC, J.A. MACDONALD, J. SPULLER TRIUMF, H.L. ANDERSON, R.J. MCKEE, LANL, AND C.S. WRIGHT, U. CHICAGO. - A search for neutrino-less \i-*e conversion, p-+Z-»e“+Z, is underway to determine whether eLectron and muon type lepton numbers are conserved separately. The TRIUMF time projection chamber (TPC) is used to detect the electrons of around 100 MeV/c which are the signal of this conversion. For 1 012 muons stopped in Ti no evidence for such a conversion has been observed so far, resulting in a new upper limit for the process. With improvements In the TPC which are now being made and more beam time, we expect to substantially improve our level of sensitivity in the near future.

ROOM 129

NUCLEAR STRUCTURE, REACTIONS AND SCATTERING

Gamma Decay of gp M Isobarlc Analogue: Resonance In ^9V . C. PRUNEAU, M.B. CHATTERJEE, C. RANCACHARYULUf and C. ST. PIERRE, Physics Department. Laval University. Quebec - In continuation of our studies of the analogue -antianalogue gamma transition strengths in ].f—2p shell nuclei, we have located the gç/2 isobaric analogue resonance in ^ V by ^°Τ1(ρ,γ) reaction at Ex = 11.15 MeV. The resonance is also seen in (ρ,ρ'Υ) channel.. The angular distributions for (ρ,γ) and (ρ,ρ'Υ) channels and the decay modes allowed the identification of the resonance to be of J^ = 9/2+ . The experimental results will be presented and the comparison will be made with the systematics of the other lf-2p shell nuclei.

^ r o m Accelerator Laboratory, Univ. Saskatchewan, Saskatoon.

DK2 The Branching Ratio in the Decay of ‘Be.* H .C.EVANS, I.P. JOHNSTONE, J.R. LESLIE, W. McLATCHIE, H.-B. MAK and P. SKENSVED, Queen’s Univ. and T.K. ALEXANDER, Atomic Energy of (^nada Limited - Chalk River Nuclear Labs. - A measurement of the branching ratio for EC decay of 7Be to the 477 keV level in 7Li is reported.The reaction 10B(p,a)7Be was used and the 7Be recoils were detected and stopped in a transmission particle de­tector. The absolute γ-ray emission rate of 477 keV γ-rays from the implanted detector was determined using a well shielded intrinsic Ge detector. The absolute efficiency of the Ge detector was established using 22Na, 137Cs and Θ®Υ standard sources. A value of 11.4 ± .7% was obtained for the branch to the 477 keV state. This is within 2 standard deviations of the published values1 and gives no grounds for questioning activation measure­ments of the astrophysically important cross section for the JHe + 4He capture cross section2^

1 F. Aj zenberg-Selove, Nucl. Phys. A320, 1 (L979) .J.L. Osborne et al., Phys. Rev. Lett. 4Θ, L664 (1982) , R.G.H. Robertson et al. Phys. Rev. C 27, IL (1983) .Supported by the Natural Sciences and Engineering Research Council of Canada.

?nDK3 Shape Factor of the Beta Spectrum of F.*

D.W. HETHERINGTON, A. ALOUSI and R.B. MOORE, Foster Radiation Laboratory, McGill U. and L. LESSARD, Laboratoire de Physique Nucléaire, U. de Montréal - The shape factor of the g- spectrum of ^UF, which is considered a good test of the Conserved Vector Current hypothesis in weak interactions, has been measured. 20p was produced by a 2.5 MeV deuteron beam from the Université de Montréal's Tandem accelerator. The beta spectrum was measured with a Germanium detector in a new horizontal bore superconducting solenoid. The response function of the detector was calculated by a Monte-Carlo simulation and verified with several beta spectra. Preliminary analysis finds a shape factor for 20p in agreement with that predicted by the C.V.C. theory.

*Work supported by NSERC, Canada

DK4 The β~ Strength Function Obtained From Beta Spectra.* R. IAFIGLIOLA, H. DAUTET, J.K.P. LEE and S.W. XU, Foster Radiation Laboratory. McGill U. - A ΔΕ-Ε telescope, consisting of a "key-hole" Si δ Ε- detector (300 pm x 200 mm2) and a Ge(HP) E-detector (15 mm x 500 mm2) has been use(j to 0btaiη β- spectra of neutron rich Rb isotopes, produced at the IS0L facilities of McGill University and of the High Flux Reactor at Brookhaven National Laboratory. Simultaneous 6” and γ-rays accumulated from the same detector system allowed a clear separation of pure β- spectra, free from the contributions of the daughter and parent decays. These spectra, after correcting for the system response function, were transformed into β - feeding intensity distributions, from which the β" strength functions can be deduced. The procedure was applied to odd A Rb isotopes and results are in good agreement to those obtained from other experimental methods. The beta strength functions derived will be discussed with theoretical calculations.

*Work supported by NSERC, Canada

differential cross sections as small as been observed for elastic scattering at transfer of 1.35 GeV/c. The motivation experiment and its detailed design will

60 pb/sr have a momentum for this be discussed.

^Supported by the NSERC of Canada.**On leave from the Weizmann Inst, of Science, Rehovot, Israel.

DK7 Non-Local Effects in Plon Photoproductio n . L. TIATOR, TRIUMF, and L.E. WRIGHT, Ohio University. - Based on a DWIA model, cross sections for pion photoproduction from light nuclei in the lp-shell were calculated. For the first time a complete treatment of non-localities in the production mechanism has been performed in a momentum space calculation. Recent experimental Information on

,irr ) 14Bg.s was analyzed and the complete density matrix could be determined. Around the minimum of the Ml cross section a sensitivity on the pion wave function Inside the nucleus has been found which gives rise to a substantial change of the pion wave function obtained with standard optical potentials.

DK8 Electro-Disintegration of 2H with Pola rized Beam and Target. C 7 Y . CHEUNG & R.M. WOLOSHYN, TRIUMF. - The asymmetry with respect to change in sign of the electron longitudinal polarization Is calculated for the exclusive 2H(e,e'n)p and Inclusive 2H(e,e')np reactions on a polarized deuteron target. The sensitivity to the neutron electric form factor Is discussed.

ROOM 144

INTERMEDIA TE ENERGIES

DK5 Neutron Nuclear Matter Density Studies from tt~ Elastic Scattering on Sulfur and Magnesium Isotopes. W. GYLES, R.R. JOHNSON, Β .ΤΓ. BARNETT, R. TACIK, H.W. ""ËOSER, G.J. LOLOS, E.L. MATHIE, UBC, R. SOBIE, T . E . DRAKE, U. of Toronto, C. WIEDNER, M.P.I. Heldelburg, J. ALSTER, Tel-Aviv U . - Differential if” elastic cross sections have been measured for 36S, 34S, 32S, 26Mg, 24Mg, targets at 50 MeV. Scattered pions were momentum analysed by the Q Q D1 or QD ( 3&S) spectrometer. Differences In neutron distributions between Isotopes are studied using an optical model and the data.

R. Sobie., Contribution to CAP (1983).

DK6 in Search of a Tredecabaryon Resonance·* K.P. JACKSON, R. ABEGG, R.E. AZUMA, D . H . BOAL, C. BROUDE**,J.M.D'AURIA, R.E.L. GREEN, R. HELMER, R.G. KORTELING, & C.A. MILLER, TRIUMF, Simon Fraser U n l v ■, & Unlv· of Toronto. - A somewhat speculative experiment is inprogress at TRIUMF to search for possible narrow states in the compound nucleus *3N formed as resonances In the elastic and Inelastic scattering of protons from ^2C at incident energies In the range from 185 to 500 MeV. The proposal Involves the use of the Medium Resolution Spectrometer (MRS) to Identify protons scattered at large angles in the population of specific low-lying states in the residual nucleus. In the initial phase of thisexperiment to demonstrate the suitability of the MRS,

DLl A study of the 09g-j (n n <y ) 209g-j reaction. J-S. T^AI, W.V. PRFST'JICM and T.O. KENNETT, Danartnent of Physics, McMaster University - ExDeriments have been per­formed with a view to obtaining the gamma ray spectrum between 0.4 and 7.5 MeV originating from neutron inelastic scattering by 209βί_ in these measurements, a new irradiation facility designed to allow reactor fast neutron flux to excite the states of the target nucleus is employed The energies and intensities of the gamma rays obtained are extracted by means of Bayesian deconvolu­tion These results enable us to determine the levelenergies of 209g-j_ jn comoarison, our present work extends the data reported by Demidov et al/ . A de­tailed transition scheme of 209g-j win be discussed.

^Kennett, T.J., Prestwich, W.V. and Robertson, A.Nucl. Instr. and Meth. 151_ (1978) 285.

( ? )'Demidov, A.M., Govor, L.I., Cherenantsev Vu. K., Kurchatov, I.V., Ahmed, M.R., Al-Najjar, S., Al-Amili, M.A., Al-Assafi, N. and Rammo, N. Atlas of gamma-ray spectra from the inelastic scattering of reactor fast neutrons. Moscow Atomizdat (1978).

60

DL2 Proton Inelastic Scattering at IntermediateEnergies and Dirac Equation Based Optical Potentials*H.S. SHERIF and R.I. SAWAFTA, Univ. of Alberta - The Dirac Equation based optical potential which is used to describe proton elastic scattering at intermediate ener­gies can be reduced to an effective Schrodinger equival­ent potential. This latter potential is generalized to an extended optical potential appropriate for a treatment of inelastic excitations of collective states. The gen­eralized potential is found to have a deformed spin- dependent interaction of the full Thomas form1 plus an additional ’small' term. Comparisons are made between predictions for inelastic scattering observables calcula­ted using this potential and those based on a non-relati­vistic Schrodinger equation based potential of the stand­ard form. Results of these comparisons for both cross section2 and analyzing power will be discussed.*H. Sherif and J.S. Blair, Phys. Lett. 26B (1968) 489 2G.R. Satchler, Nucl. Phys. A394 (1983) 349 *Supported in part by NSERC

D L 3 Lifetime Measurements in 97T c -* E. ADAMIDES,W. McLATCHIE, P. SKENSVED and J.R. LESLIE, Queen's U n i v . - The lifetimes for 11 states In 97Tc and limits for 12 others have been obtained by the Doppler-shift-attenua- tion method via the 97M o ( p ,ηγ)97Tc reaction at 3.5 M e V . The measured lifetimes in combination with previously existing data on 97Tc 1,2 * 3 enabled the determination of the B(oL) values for many transitions . In some cases the lifetimes have helped to uniquely determine spins and multipole mixing ratios. On the basis of the measured B(E2) and B(M1) values the collective nature of some low lying states is discussed.

*Xenoulis A.C. and Kalfas C.A., Phys. Rev. C 2 0 , 145 (1979) .

2Landsberger S ., et a l ., Nucl, Phys. A 3 3 9 , 238 (1980).

3Kajzys G., et al., Phys. Rev. C26, 1451 (1982).

4Kajzys G., et al., Phys. Rev. C26, 1462 (1982).

*Research supported by NSERC (Canada).

DL4 New Improvements in the **Be(3He,p) 1 *B Polariza­tion Measurement.* J. POULIOT, P. BRICAULT, M. NÂCfiABB, L. PCfrVlN,“B.K.“5lNHA, R. ROY and R.J. SLOBODRIAN, La­boratoire de Physique Nucléaire - Denartement de Physi- cme. Université Lavai - Large differences between tne polarization in the ^fee(3He,n)1*B reaction at 14 MeV and the analyzing power in the inverse reaction have been observed*; polarization values were obtained either with silicon or carbon analyzers. For more detailed effec­tive analyzing power calculations, new cross-section da­ta were collected in the angular region of interest and in the energy range covered by the energy loss of the beam in the *Be target. Moreover, in a setup minimizing multiple scattering effects, we performed polarization measurements with improved angular resolution (a factor of two) in the above reaction. Those improvements will be discussed and experimental results presented.

R.J. Slobodrian a t., Phys. Rev. Lett. 47 (1981)1803; J. Pouliot et a t., to be published.

^Supported in part by N.S.E.R.C. and the M.E.O.

DL5 In-beam γ- ray Stud ios o f ΐϊ2> 11<4 * .* V DJANZEN, J .A. CAMERON, J.C. WADDINCTON and R.B. SCHUBANK,McMaster University . Hamilton. Ontario - High-spinstates in i 12*ii‘+*l ^|Te nuclei have been studied via(ZáNa,p2n) reactions, using in-beam γ-excitation, γ-γ coincidence, and angular distribution measurements. Excited states in the yrast bands of spin up to 18+ have been observed, for example a strongly-populated AJ=2 band in 11 2Te extending up to 18+ which inclides levels at 0.689, 1.476, 2.297, 3.361, 4.106, 4.707, 5.420, 6.284, and 7.231 MeV. A number of side bands have also been established. The systematics of the resulting level structures will be discussed.

A Supported by NSERC

DL6 The 13C(p ,y ) 1uN Reaction. R.E. AZUMA, J.D.KING and J.B. VISE, University of Toronto, C. ROLFS and H.P. TRAUTVETTER, University of Munster - The yield of y rays to the ground state and several excited states of iHN has been measured from 950 keV down to 250 keV proton energy at Toronto, and down to 168 keV proton energy at Munster; the latter measurements are being extended to 100 keV or less. A broad resonance at 560 keV due to excitation of the (1“ ;1) state at 8.062 MeV is observed, as well as a narrow resonance at 450 keV due to the 7,967 (2“ ;0) state. Transitions from the 8.062 MeV state to all levels up to 5.690 MeV have been observed„ An improved decay scheme for the 7.967 MeV state has been obtained. Astrophysical S-factors extracted from our data are somewhat higher than previously reported values1 (a factor of 2 at 250 keV) and measurements to lower proton energy are being carried out to provide for better extrapolation to near­zero energy.

^Fowler, W.A. Caughlan, G.R. and Zimmerman, B.A., Ann.Rev. Astr. Astrophys., 5, 525 (1967).

DL7 Fusion and Neutron Transfer Cross Sections for 13C+1 °B and 13C+TAB Reactions at Subbarrier Energies.B. DAa^\HAPATRA+, b. ClÜEQ and V. LAHLoU,~lIniyersitg Laval, Québec - The study of the 13C+10B anti-13C+11B reactions provides a sensitive test on the influence of the neutron transfer channels on the fusion cross section, since the neutron transfer reactions occur in the first, but are absent in the second system because of the negative Q-value. The cross sections for the 1 ° B ( 1 3C,12C)11B~4.45 and 6.74 MeV neutron transfer reac­tions and the total reaction cross sections were obtained, in dependence on the incident energy between Ec.m. =2.4 MeV and ~ 6 MeV, from the yields of the characteristic and total γ-rays, detected with two Nal detectors in nearly 4ύτ geometry. The fusion cross sections obtained for the two systems are tie same, what demonstrates that the fusion process is unaffected by the presence of large neutron-transfer probabilities.

^Present address: Physics Department, University of Burdwan, India.

d l8 Charge-state Fractions of 50 to 350 KeV Helium Ions in Different Materials. G.b. KU33, U. ILHkLAUL I.G. ABtL, C. BUUCHtR and G. GOBEIL, INRS-Energie, Varen- nes, Québec.- In the process of measuring implanted H profi les in thick targets using elastic recoils passing through a magnetic filter, we are forced to consider the charge-state ratio of the helium ions scattered by the target. He+ ions are accelerated to 350 KeV and steered towards a thick target of a given material. Using a magnet and a multichannel analyser, we measure the res­pective fractions of He°, He+ and He++ scattered at an angle of 45° from the incident beam. In this experiment we consider the energy spectrum of the scattered He at energies ranging between 50 KeV and maximum scattered energy. The analysis of this spectrum gives us informa­tion concerning the influence of the material on the charge-state ratio of scattered ions using this geome­try. Finally, we compare our results with those obtain­ed by other groups with helium beams passing through thin targets.

DL9 Elastic Scattering of Protons from ^He at Interme- dlate Energies.* A. BRACCO, H.P. GUBLER, D.K. HASELL,W.P. LEE, W.T.H. VAN OERS, U of Manitoba, R. ABEGG, C.A. MILLER, TRIUMF, J.M. CAMERON, L.G. GREENIAUS, D.A. HUTCHEON, G.A. MOSS, G. ROY, U of Alberta, M.B. EPSTEIN,D.J. MARGAZIOTIS, Calif. State U. L.A., A.W. STETZ, O REG. STATE U, H. POSTMA, Techn. Hogeschool Delft. - Different­ial cross sections and analysing powers for proton elastic scattering from 3He have been measured at 200, 300, 415 and 515 MeV. The angular distributions cover the range from 20° to 150° cm. These data together with data from the literature in the energy range 100 to 1000 MeV, have been analyzed within the framework of the Glauber multiple scattering theory. Using a spin-indepe­ndent, parameterised form for the nucleon-nucleon scatte­ring amplitudes good agreement was obtained with the differential cross sections* However, calculations per­formed using the complete isospin-spin-dependent nucleon- nucleon scattering amplitudes are in poor agreement with the experimental data. In studying this discrepancy off- shell effects, different wave functions, charge exchange, and spin flip processes have been examined. Improvements to the calculations will be discussed.

*Work supported in part by NSERC, Canada

DL10 Energy Dependence for (p,w~xn) Reactions on Bismuth. M. D0MBSKY & J.M. D'AURIA, Simon Fraser Univ., G. SHEFFER AND T. RUTH TRIUMF, J.L. CLARK, LASL/LAMPF,~T.E. WARD, IUCF & A. YAVIN, Univ. of Tel A v i v . - Despite continued interest the mechanism of negative pion prod­uction from proton-nucleus interactions is still unclear, while inclusive and exclusive data do exist for low-Z targets, little information is available for heavy Z tar­gets, and in particular, the dependence on incident pro­ton energy. Recent studies using 200 MeV protons in a traditional radiochemical approach at BNL indicate the feasibility of obtaining angle integrated total reaction cross sections for the production of At isotopes from 209Bi(p, π~χη) 2 ^ ”xAt reactions. These display marked predominance of neutron emission products over the coh­erent product 2 1 °At. While different theoretical app­roaches do exhibit reasonable agreement with these data, these different calculation do diverge significantly with increasing proton energy. This paper reports on a coll­aborative effort to continue these types of measurements for incident proton energies from threshold to 800 MeV. Studies were performed at IUCF, TRIUMF, and LAMPF, and available results will be presented and discussed.

DL11 Pion Induced Fission on DLi for incident pion energies of 60, 75, and 90 M e V .* G.J. LOLOS**, R.R. JOHNSON, P. COUVERT***, J. MCKENNA, R. MYERS, P. LORRAINE****, I. SPADINGER*****, De p t . of Physics., U B C .- Differential cross sections for the pionic fission reaction ^Lif ir+ . 3He) 3He have been measured for 0ctn =41° and at 60, 75 and 90 MeV incident pion energies. The energy dependence of the differential cross section is found to follow an exponential decrease with increasing incident pion energy. Our results are compared to theoretical predictions based on ^Li clustering assumptions, and found not to be in agreement with either of the two models developed at present.

*Work supported in part by NSERC, Canada.**Now with the Physics Dept. U of Regina, Regina Sask. ***and Dept, of Phys. N/ME, CEN Saclay, 91191 Cif-sur- Yvette, Cedex, France ****NSERC Summer Students.*****TRIUMF Summer Student.

DL12 Proton Induced Exclusive Pion Production from 12C.* G.J. LOLOS**, E.G. AULD, W.R. FALK***, G. GILES,G. JONES, B. MCPARLAND, R . B . TAYLOR****, P.L. WALDEN & W. ZIEGLER, Dept, of Phys ics UBC & TRIUMF. - We have measur­ed angular distributions for the differential cross sect­ions and analyzing powers in 2C( ,Τ, π+ ) 1 C* leading to discrete final states * 13CgS ·, and13C g . 50MeV for incident proton energies of 200,216, 225, 237 and 250 MeV. The transition leading to the ^3CgS ., best described by a single particle configur­ation, exhibits large energy dependence for the analyzing power distribution for energies higher than 200 MeV. The A n for the transition leading to the ^3C g. 5Q state, on the other hand, which best fits a 2p-lh configuration is nearly independent of incident proton energy Indicating perhaps a sensitivity in the reaction mechanism. Our results are compared with recent theoretical predictions based on microscopic two nucleon model calculations.

*Supported by NSERC, Canada.**Now with the Dept, of Physics, Univ. of Regina, Sask. ***Dept. of Physics, Univ. of Manitoba, Winnipeg. ****Dept. of Phys., James Cook U., Queensland, Australia

DL13 The 12C(j?, tt+ )X Reaction at 400 and 450 MeV* .W.R. FALK, Dept, of Physics . , U of Manitoba, E.G. AULD,G.GILES, G. JONES, G.J. LOLOS, W. ZIEGLER, Dept, of Physics., U B C , P.L. Walden, TRIUMF. - Inclusive measurements of the differential cross section and analyzing power of the (p,*+ ) reaction on 12C have been performed at 400 and 450 MeV incident proton energy. The energy domain investigated spans the region of ïï energies in the p p +d 7T+ reaction which was measured simultaniously. The latter reaction was used in calibrating the 65 cm Browne-Buechner spectrometer, "Resolution", used in detecting the pions. Measurements were made in the angular range 46° to 90° (Lab). The experimental analyzing power in the 12C(p,ir+ )X reaction exhibit the trend of the analyzing power of the pp*dπ+ reaction at forward angles, but at backward angles they are considerably larger. Comparison of the data with the quasi-free model that incorporates the free pp+d tt+ data, will be presented.

*Supported by NSERC of CANADA.

62

DL14 Plon Double Charge Exchange a t Low Energy.I. NAVON, D.A. BRYMAN, M. LEITCH, T. NUMAO, A. OLIN, P. SCHLATTER, U. Vic and TRIUMF, G. AZUELOS, P. DEPOMMIER,R. POUTISSOU, U. de Montreal, M.S. DIXIT, C.K. HARGROVE, H. MES, NRC, R.A. BURNHAM, M. HASINOFF, J.M. POUTISSOU, U B C , J.A. MACDONALD, J. SPULLER, TRIUMF, M.A. MOINESTER, Tel-Aviv Univ., H. BAER, M. COOPER, LAMPF . - Pion double charge exchange (DCX) is a sensitive probe of details of the pion-nucleus potential, and of nucleon-nucleon correlations, since at least two nucleons must take part in the interaction. Despite its importance, DCX has not been measured previously at low energy, because of the experimental difficulty posed by the small cross section. Theoretical models give contradictory predictions of the magnitude and shape of the distribution in this energy range. An experiment to measure the angular distribution of 1 ( Γ , ϊ") at 50 MeV, is underway in the Time Projection Chamber (TPC) at TRIUMF. The TPC is especially suited to measure this reaction due to its large acceptance, and its ability to identify the sign of the particle's charge.

DL15 Pion Absorption on ^He at 65 MeV.* K.A. ANIOL, R.R. JOHNSON, R. TACIK, W. GYLES, B. BARNETT, H.W. ROSER, Dept, of Physics, U B C , D. ASHERY, J. ALSTER, M.MOINESTER, A. ALTMAN, J. LICHTENSTADT, Tel A v iv U n iv., D.R. GILL, J. VINCENT, TRIUMF, R. SOBIE, U. of Toronto,H. GUBLER, U. of Manitoba & S. LEVINSON, Northwestern Univ. - Angular distributions associated with pion absor­ption on ^He have been measured. Both positive and negative pion reactions exhibit angular correlations peaked at an angle corresponding to the d(ir,2p) kinematic conditions. The ratio of total cross sections σ( π“+ ρ ρ +p+n)/σ( tr++pn>p+p) = .04 ± .008. This is substan­tially larger than that observed at 165 M e V1 and smaller than that observed for stopped π” absorption2. In the nd centre of mass we find the angular distribution to be symmetric about the 90° for the π++ρη-*-ρ+ρ case and to be asymmetric for the ττ“+ρρ+ρη reaction.

^D. Ashery et, al. Phys. ReV. Lett. 47 895(1981).2 D. Gotta et, al. Phys. Lett. 112B 129(1982).♦Supported by NSERC

DL16 Instrumentation for an Experiment to Test Charge Symmetry in n-p Elastic Scattering.* J. BIRCHALL, N.E. DAVISON, H.P. GUBLER, W.P. LEE, P.R. P0FFENBERGER, J.P. SVENNE, W.T.H. VAN 0ERS, U OF Manitoba, R. ABEGG, C.A. MILLER, TRIUMF, E.B. CAIRNS, H. C00MBES, C.A. DAVIS, P. GREEN, L.G. GREENIAUS, W.J.MCDONALD, G.A. MOSS, G. ROY,J. S0UKUP, G.M. STINSON, U_ OF Alberta, H.E. C0NZETT, L B L , G.R. PLATTNER, U of Basel. - At TRIUMF an experiment to investigate the isospin-mixing, charge-symmetry breaking component in the n-p interaction is underway. The diffe­rence ΔΑ between the neutron and proton analyzing powers A n and Ap in n-p elastic scattering at 500 MeV will be measured to an accuracy of AA^O.OOl at the angle where An and Ap cross through zero. The principle of the measurement, some sources of potential systematic errors and the methods to control these systematic errors will be described. Testruns to check different components, such as proton beam polariméter, beam energy monitor, neutron collimator, spin precession magnets, neutron beam profile monitor and polariméter, 60cm x 60cm wire chambers and proton range counters were made.Results will be presented.

♦Work supported in part by NSERC, Canada.

DL17 The QQD Pion Spectrometer at TRIUMF. R.J. SOBIE & T.E. DRAKE, Univ. of Toronto, D . R . G I L L & E.W. BLACKM0RE, TRIUMF, R.R. JOHNSON, W. GYLES, B. BARNETT, R. TACIK, H. ROSER, K.L. ERDMAN, UNIV. O F BRITISH COLUMBIA, S. MARTIN, KFA, Jullch, C. WIEDNER, MPI, Heidelberg. - A low energy pion spectrometer has been designed and commissioned at TRIUMF. Recent data obtained on the M13 pion channel has

demonstrated a resolution of 800 KeV and a solid angle of 18 msr for 50 MeV pions. A comparison of the design parameters to those measured shows reasonable agreement. Also the ^2C( n+ , tt+ ) elastic differential cross section was measured at Τ π = 50 MeV and it is found to agree with previous experimental results. Planned improvements to the M13-QQD system to achieve 500 KeV resolution and long term Improvements will be discussed.

DL18 The Reaction pd-*-t7r+ at Intermediate Energies.* R. ABEGG, D.A. HUTCHE0N, & C.A. MILLER, TRIUMF, J. ARVIEUX, CEN Saclay, J.M. CAMERON, C.A. DAVIES, A. HUSSEIN, G.A. MOSS, W.C. OLSEN, G. ROY & I. VAN HEERDEN, U of Alberta.- Differential cross sections and analyzing powers of the reaction pd+fn+ in the angular regime 110°<0T+ Cra<160° have been measured at 500, 475, 450, 425 MeV incident proton energy. Polarized protons from the TRIUMF cyclotron were incident onto a solid C D2 target and the reaction products t and π+ were detected by the medium resolution spectrometer MRS and plastic scintilators, respectively. Additional data from the isospin related reaction pd-^Heir0 may be presented. Out date, will be compared with published values.

♦Work supported in part by NSERC, Canada.

DL19 Pion Radiation Capture and Charge Exchange below the Δ resonance.* A. BAGHERI, K. ANIOL, M.D. HASINOFF, D.F. MEASDAY, J-M. POUTISSOU and M. SALOMON, TRIUMF and University of British Columbia, and B.C. - ROBERTSON, Queen's University - The reactions n”p ■» γη and iTp + n un have been studied for 40 < T^ < 125 MeV on the Mil channel at TRIUMF, using a large Nal crystal to detect the γ-rays. Data have been obtained every 15 MeV and every 15° for 45° < Θ < 135°. The detailed analysis is continuing but initial indications are that the re­sults are significantly more accurate than earlier mea­surements, and are consistent with our previous data taken on the M13 channel. A preliminary assessment of the results will be presented.

♦Supported by the Natural Sciences and Engineering Research Council of Canada.

DL20 Incoherent Double Negative Pion Production in Nuclei by Intermedicate Energy Nucleons. J. A. K0PAC, D ept._of Physics., U o f Victoria, E.W. VOGT, TRIUMF. - As part of a theoretical study1 of possible multiple pion production in nuclei. We have investigated incoherent double negative pion production in the nucleus by inter­mediate energy nucleons. Low energy backward pions are created according to the isobar model. Nuclear chemistry techniques can be used to determine the reaction rates without observing the pions directly. Paul! blocking of the recoil nucleons and the Fermi momentum of the target nucleons cause significant differences between free pion production and pion production in the nucleus. The excitation function for incoherent double plon creation varies nearly linearly with the incident energy in the range from .5 to 1 GeV. For 800 MeV neutrons incident on a 2o8Pb nucleus, the inclusive cross section for double negative pion production is calculated to be 1.3 mb. The implication of those results for experiments and for models of pions in the nucleus are discussed.

^E.W. Vogt, to be published.

DL21 Suppression of Multiple Scattering in the Pion- Nucleus System»* N. de Takacsy & B.K. Jennings, TRIUMF.- It was suggested several years^ ago that multiple

scattering in the pion nucleus system was suppressed due to short range correlations and p-meson exchange. In a recent paper2 it is argued that the inelastic scattering to the first excited zero plus state in ^2C provides strong experimental evidence for such a suppression.This suppression suggests that the usual procedure of calculating pion-nucleus scattering by iterating an optical potential with a Klein-Gordon equation and cancelling the multiple scattering series with higher order terms in the optical potential is inefficient. It is better to do the multiple scattering term by term since the suppression of multiple scattering ensures rapid convergence. This is investigated numerically and further experiments are suggested.

•M. Ericson & T.E.O. Ericson, Ann. Phys.(NY)36 (1966)323 G. Baym & G.E. Brown, Nucl. Phys. A247 (1975) 395. 2B.K. Jennings and N. de Takacsy, Phys. Lett, (in press). *Supported by NSERC.

DL22 Kaon Induced Deuteron Disintegration.O.V. MAXWELL, TRIUMF. - Integrated cross sections and angular distributions are obtained for the reaction K“ d ♦ Σ“ ρ ( An) for laboratory K” momentum from threshold up to 750 MeV/c. The reaction model consists of the impulse approximation plus rescattering through an intermediate

Y* followed by pseudoscalar or vector meson exchange. In the rescattering terra, all of the well established Σ* and Λ* resonances below 1700 MeV are included with coupling constants obtained from decay widths and SU(3) symmetry relations. Initial results are presented for a simplified model In which vector meson exchanges and correlations In the final YN state are neglected. Once the qualitative features of the cross sections have been determined, more quantitative calculations incorporating vector meson exchanges and final state correlations will be attempted.

DL23 A Potential Model Calculation for Proton-Proton Bremsstrahlung. R.L. WORKMAN, Univ. of British Columbia, H.W. FEARING, TRIUMF. Progress on a new potential model calculation of proton-proton bremsstrahlung is described. The problem Is solved via the Lippmann-Schwinger equation, with Intermediate results being compared with those obtained from the soft photon approximation. The aim Is to produce a calculation which will utilize modern potentials, such as the Paris potential, which have not been used for this process before. The results of these calculations will be compared to those which were derived from some of the older potentials. Quantitative results will include asymmetries and cross sections - Including Integrated cross sections.

TUESDAY, JUNE 28, 1983

T I M E R O O M

A N N U A L B U S I N E S S M E E T I N G S O F C A P D I V I S I O N S

1 6 : 3 0 16 7 Division of Atomic and Molecular Physics1 6 : 3 0 1 6 8 Division of Condensed Matter Physics1 6 : 3 0 0 6 0 Division of Nuclear Physics1 6 : 3 0 1 6 2 Division of Particle Physics1 6 : 3 0 0 6 1 Division of Plasma Physics

TUESDAY EVENING

Reception and Banquet Royal Roads Military College (outside, weather permitting)

17:30 Receptionl-V

19:30 Banquet: A.R. Crawford presiding

Award of CAP Medals and Prizes

After Dinner Address: Dr. Patrick McGeerMinister of Universities, Science and Communications Governement of British Columbia

64

WEDNESDAY, JUNE 29,1983 CAP-CAS PLENARY SESSIONROOM: MacLaurin 144 Chairmen: G.C. Hanna

V. Gaizauskas

8:30EA1 Quantum Noise and Gravity Wave Detection

W.G. Unruh, UnloeAilty 0 $ B u llish Columbia.

Gravitational wave detection is hampered by the quantum properties of the detector (such as the two ton bars of aluminum). Ways of avoiding these difficulties will be discussed and will be related to the old problems of quantum measurement theory.

9:00EA2 Neutron Scattering Studies of Liquids and Dense Gases

P.A. Egelstaff, Guelph - WateAloo Pwgnam o a Ghaduati WoAfe In Physics

Modern neutron spectrometers have crossed a precision threshhold for the study of liquids, gases and mixtures. Some examples of the new generation of data will be given, and their significance discussed. In a few years several powerful new pulsed neutron sources will come into use, and their possible impact will be considered.

R.M. Petrie LectureSponsored by the Canadian Astronomical Society

9:30EA3 Strongly Interacting Binary Stars: Freaks or Rosetta Stones?

M.J. Plavec, VepaiUment of, Astaonomy, UnloeAilty ol Call^oanla, Loi Angeles

10:30 Break

WEDNESDAY, JUNE 29, 1983 ROOM: MacLaurin 144 Chairman: A.R. Crawford

10:45 Annual General Meeting of the Canadian Association of Physicists

WEDNESDAY, JUNE 29,1983 ROOM: 167 (Elliott)Chairman: V. Gaizauskas

10:45 Annual General Meeting of the Canadian Astronomical Society

65

WEDNESDAY, JUNE 29,1983 BIOPHYSICAL MEMBRANESROOM 168Chairman: M. Bloom

13:00FAI Biomembranes, Basic Science and Future Technology

D. Chapman, Vept. of BiochemibVuf ê Chemistiy, Royal F-tee Hoipital School of Medicine.

In recent years there has been great interest by many scientists in the study of biomembranes. Physical techniques, including calorimetry and a range of spectroscopic techniques, have been used, including ir., nmr., esr., and fluorescence and phosphorescence methods. This talk will show how basic information has been built up about the structure of biomembranes, leading to the concept of a lipid bilayer structure providing the basic matrix for proteins which span the bilayer. The dynamics of the lipids in the bilayer have been measured eg. gauche-trans isomerism of the chains, lipid diffusion and phase transitions. Protein dynamics including protein rotational diffusion and lateral diffusion have been studied. The nature and dynamics of the perturbation caused upon the lipid by intrinsic proteins in the bilayer structure has also been actively in­vestigated. Increasingly physical techniques such as F.T.I.R. spectroscopy are being applied to study the mechanisms and laolecular changes involved in energy transduction and ion transport. Difference spectra and isotope substitution in the membrane proteins have been used. Finally the ways in which this basic information may lead to new technological developments including phos­pholipid polymers and biocompatible surfaces will be described. The use of Langmuir Blodgett films of phospholipid molecules to produce sensor devices will also be indicated.

13:50FA2 Mechanical Calorimetry of Synthetic and Natural Membranes

E .A. Evans, 0ept. of Academic Pathology, UniveASity of BAeliih Columbia

T h e l a m e l l a r c o n f i g u r a t i o n o f b i o l o g i c a l m e m b r a n e s t r u c t u r e s i n t h e r e s u l t o f t h e p r e f e r e n t i a l a s s e m b l y o f t h e a m p h i p h i l i c m o l e c u l e s i n t o a n i s o t r o p i c m i x t u r e s o f l i p i d s , p r o t e i n s , e t c . B e c a u s e o f t h e s t r o n g p r e f e r e n c e f o r t h e l a m e l l a r a r r a n g e m e n t , t h e e n c a p s u l a t i n g m e m b r a n e o f a b i o l o g i c a l c e l l o r s y n t h e t i c l i p i d v e s i c l e b e h a v e s a s a c l o s e d t h e r m o d y n a m i c s y s t e m f o r p e r i o d s o f t i m e o n t h e o r d e r o f h o u r s . S i n c e t h e r e i s n o e x c h a n g e o f m a t e r i a l , m e c h a n i c a l e x p e r i m e n t s c a n b e u s e d t o i n v e s t i g a t e t h e p h y s i c a l s t a t e o f t h e m e m b r a n e i n s i t u . When e v a l u a t e d a s a f u n c t i o n o f t e m p e r a t u r e , t h e s e e x p e r i m e n t s c a n b e u s e d t o d e c o m p o s e t h e m e c h a n i c a l w o r k i n t o i n t e r n a l e n e r g y a n d h e a t o f d e f o r m a t i o n c o n t r i b u t i o n s . C o m p a r i s o n o f t h e r e s u l t s f o r c o m p o s i t e c e l l m e m b r a n e s t o t h o s e o f w e l l - d e f i n e d s y n t h e t i c m e m b r a n e s p r o v i d e s q u a n t i t a t i v e i n s i g h t i n t o t h e c h e m i s t r y o f n a t u r a l m e m b r a n e " m i x t u r e s " . M e m b r a n e m e c h a n i c a l p r o p e r t i e s a l s o p l a y a s i g n i f i c a n t r o l e i n c h e m i c a l i n t e r a c t i o n s b e t w e e n c e l l u l a r a n d v e s i c u l a r s u r f a c e s . E q u i l i b r i u m o f m e m b r a n e - m e m b r a n e c o n t a c t s i n v o l v e t h e c o m p e t i t i v e a c t i o n s o f a t t r a c t i v e c h e m i c a l f o r c e s a g a i n s t m e c h a n i c a l r i g i d i t y o f t h e m e m b r a n e s u b s t r a t e s . D e f o r m a t i o n a n a l y s i s c o u p l e d w i t h k n o w n m e c h a n i c a l p r o p e r t i e s c a n b e u s e d t o d e t e r m i n e t h e c h e m i c a l a f f i n i t y b e t w e e n m e m b r a n e s u r f a c e s .

14:30FA3 A Physicist's Model Membrane

J.H. Davis, UniveAiity of Guelph

Biological membranes consist of a mixture of lipids and proteins arranged in a bilayer structure. The large degree of disorder and molecular heterogeneity are two of the factors impeding investigation of the molecular physics of the natural systems. The phase equilibria of model membranes composed of synthetic amphiphilic peptides (as protein analogs) and synthetic CH labelled phospholipids can provide quantitative information on the thermodynamically important interactions among membranes components - specifically, between proteins and lipids. Deuterium NMR spectroscopy has been developed to the point where it now provides a quantitative means of studying phase equilibria in membrane systems. A partial phase diagram of a peptide/phospholipid model membrane has been determined and will be discussed in terms of a simple thermodynamic model of the interactions between proteins and lipids.

15:10FA4 Theory of Phospholipid Monolayers and Bilayers

A. Georgallas, McGill UniveAiity and D .A. Pink, St. Fiancii XavieA UniveAiity

66

WEDNESDAY, JUNE 29,1983 ORGANIC SUPERCONDUCTORS, METALLICROOM 060 GLASSES AND ROTA TIONAL TUNNELINGChairman: L. Caron

13:00FBI Far Infra-Red Properties of the (TMTSF)2X Compounds at Low Temperature

T. Timusk and H.K. Ng, McMaAteA Uïiiv&UÀJiy

The quasi one-dimensional organic materials have unusual far-infrared properties in their conducting state. The high dc conductivity of these materials in the chain axis direction would lead one to expect a Drude-like behaviour in the far-infrared. Instead the materials exhibit a gap-like region of low conductivity below 100 cm- 1 . This is borne out by our recent results on the optical properties of (TMTSF)2010ι* in the 4 cm-1 to 400 cm”1 region.We interpret the gap as a frequency region where there are no momentum conserving processes for the absorption of electromagnetic radiation. A puzzling feature of the spectra is the total absence of the Drude tail that would be associated with the high dc conductivity in a single particle picture. An alternate picture is one where the current is carried by sliding charge density waves or superconducting fluctuations. We will discuss our results in terms of these models.

13:40FB2 Metallic Glasses: The Simplest Type of Metal?

J.O . Strom-0 Is en, MeG-cff. UyilveJU'Lty

The properties of metallic glass alloys are in many ways simpler than those of their crystalline counterparts. The absence of long range order means that transport properties may be crudely understood on the basis of the simplest free electron model ; also, glasses show far fewer difficulties in alloy formation. The general uniformity of glassy structures allows glassy alloys to reveal fundamental trends in behavior which in crystalline alloys may be masked by change of structure or separation of phase.A brief review of glass formation and glass stability will be followed by an examination of the superconducting and transport properties of some zirconium based glasses containing Cu, Ni, Co or Fe. These materials illustrate the comparative simplicity of glasses and, in particular, offer an excellent matrix to study the interaction between superconductivity and itinerant magnetism.

14:20FB3 Rotational Tunneling of Atomic Groupa in Solids: __ _

A Review of Experimental Techniques in the Energy Range 10 1® to 10 ^ eV. M.M. Pintar, ttnivQ A A lty 0|J WciteÀloO

An atomic group or a molecule embedded in a solid matrix may undergo at high temperatures thermall) activated jump-like reorientations. At low temperatures these reorientations diminish in frequency and the atomic groups become delocalized. They could be described by either symmetric or antisym­metric spacial wave functions and are said to. be in a state of "rotational” tunneling. The energy difference between the antisymmetric and symmetric state is the so called tunneling energy Since it is very strongly dependent on the hindering potential (which is supplied by the lattice) any minute change in the lattice causes a change in ωτ · For this reason many experimental tech­niques were employed to measure ωτ of several symmetric atomic groups in solids. The most famous atomic group studied is the methane molecule and the most successful technique the neutron inelastic scattering (NIS) spectroscopy. Unfortunately, however, the energy resolution of the NIS spectro­scopy is limited to ^0.5 peV, while in many interesting situât ions is less than 0.5 peV. In the energy range below 0.5 peV the nuclear magnetic resonance (NMR) is a very effective tunneling spectroscopic technique. A brief discussion on some novel methods employing NMR which cover the energy range 10-lil to 1Π-6 eV will be followed bv a discussion on NIS. Tunneling spectra obtained by these methods will be shown. On the basis of the experimental information about tunneling the meaning of the correlation time characterising molecular reorientation will be discussed.

67

WEDNESDAY, JUNE 29. 1983ROOM 062Chairman: J.M. Cameron

NUCLEAR PHYSICS V: INTERMEDIA TE ENERGIES

13:00FC1 Radiative Capture at Intermediate Energies

D.A. Hutcheon, TRIUMF - UniVCAiiXy o& BfUtcih Cotumb-La.

Proton radiative capture (or the inverse photo disintegration reaction) involves large transfer of momentum at intermediate energies, and may be the key to the understanding of reactions such as (ρ,ττ+) and (d,p). Various mechanisms— short range correlations, Δ-excitation meson exchange currents, and others— have been invoked to account for observed (ρ,γ) cross sections. In addition, the possible breakdown of detailed balance in 2H(p,y)3He and its inverse reaction, and evidence for 6-quark configurations ^n the 3H (p, γ) 2H_^reaction have been suggested. Experiments at TRIUMF on the reactions 2Η(ρ,γ) 3He, ^ ( ρ , γ ^ Η ε , and 'Η(η,γ)2Η will be described and their significance discussed.

13:45FC2 A New Measurement of the Tt+ev Branching Ratio

D.A. Bryman, TRIUMF - UniveAi-iAij of, lUctofUa.

Γ( TT-*e v + ι-ΐνγ)A new measurement of the *+ev branching ratio yields (1.218i0.014)xl0 ‘.

Γ( π +uv + ττ+μνγ)The measured value Is in good agreement with the predictions of the unified theory of weak and electromagnetic interactions incorporating electron-muon universality. The experimental measurement of the branching ratio will be described and the constraints placed on current theories will be discussed.

WEDNESDAY, JUNE 29,1983 LASER PLASMAS IIROOM 061Chairman: A. Ng

Details of the following papers will be given at the poster session on Tuesday afternoon.

13:00FD1 Coupling and Radial Transport of Energy in CO2

Laser-Produced Plasmas. N.IC Burnett and G.D. Enright, National Research Council of Canada - An extensive series of experiments have been made to characterize the coupling and radial transport of energy in the focal region of CO2 laser-produced plasmas at intensities ^2-3 x 10l4 Wcm"2. Stud ies of rear surface optical pyrometry, layered target Kq, emission, and shock wave velocities have indicated that a Maxwellian distribution of electrons, characterized by a 15-20 keV M temperature", couples M .0% of the incident laser intensity into the target in the focal region. These results have been confirmed by recent measurements which have employed Von Hamos x-ray spectrometer to spatially resolve the Κφ like emission from A1 targets. In the focal region shifted Kq components from highly ionized ions are clearly visible. The relative intensities of these lines are sensitive to both the hot electron temperature and the target coupling efficiency and thus provides a useful diagnostic of the interaction process. It is apparent that the hydrogen-like and at least part of the helium-like resonance line emission that has been ob­served in these plasmas and attributed to thermal plasma emission is Ka emission from excited states of He-like and Li-like ions.

13:30FD2 Fast electrons produced at the quarter critical

density in la ser irradiated plasmas.* J. MEYER, J.E. BERNARD, B . H I L K O , H. HOUTMAN, G. MCINTOSH and R. POPIL, Dept, of Physics, UBC, Vancouver. B .C. - The production of fast electrons by both two plasmon decay and stimulated Raman scattering is investigated in a CO2 laser irradiated N2 gas jet. Two plasmon decay waves of initially 1.8 laser wavenumbers are shown to trap elec­trons and subsequently heat them to mean energies exceeding the phase energy by a factor of five whilst stimulated Raman electrons are observed at the phase energy of the absolute instability. Both instabilities are terminated by profile modification after heating more than 1% of all the electrons in the focal volume.

* Supported by NSERC.

1 4 : 0 0FD3Design and Performance Characteristics of a High

Power KrF Laser Facility*.. D.C.D. MCKEN, R. FEDOSEJEVS and A.A. OFFENBERGER, Univ. of Alberta - A short pulse ultraviolet laser facility with a nominal output energy of 2ÛJ has been constructed for studying laser/ matter interaction at target irradiation intensities approaching 5 x 1 013 watts/cm2 . The facility consists of a KrF discharge laser front end, an electron-beam pumped KrF power amplifier and an optical pulse com­pression sub-system utilizing beam stacking and stim­ulated backward Raman scattering in methane. The entire facility, including all ancillary systems, was fabricated in-house. The present paper includes a discussion of the overall concept as well as design details pertinent to the research program. Operating characteristics will be discussed including pre­liminary optical extraction results.

* Supported by the Alberta/Canada Energy Resources Research Fund.

14:30FD4 Measurement of plasma parameters in a low

density discharge using CO2 laser scattering from launched w a ves.* P. BRODEUR and H.W.H. VAN ANDEL, Université de M ontreal - The dispersion relation for launched ion acoustic waves in a flowing plasma was measured over a wide range of k-vectors using a coherent CW CÛ2 laser scattering arrangement. Several plasma parameters, such as electron temperature, electron density and plasma flow velocity are determin­ed by fitting the measured dispersion relation to the theoretically predicted dispersion. The experimental system, which is being developed for fluctuation measurements on Textor and the Varennes Tokamak, will be described, and details of experimental techniques involving a combination of heterodyne optical mixing and phase sensitive detection will be presented.

’’'Research supported by NSERC.

68

WEDNESDAY, JUNE 29,1983 SURFA CE SCIENCEROOM 162Chairman: R.N. O’Brien

13:00F E1 The Electrical Double Layer ind Colloidal Particles

S. Levine, Apptiid Wa+l 4, ManakeAteA UyUveA A ity C » " c '

13:45F E2 Membrane Processes and Permeable Surfaces

C« Forgács and R.N. O ’Brien, KeAiaAck and V&vclopment ïn A t t tu te , , Bin Gunion U niv& iA ity

14:30F E 3 Electrochemistry at Polymer Covered Electrodes

K.S.V. Santhanam, Tata Institute, oá Fundamíntol Ri6iOAck, Bombay

WEDNESDAY, JUNE 29,1983 CANADIAN LONG-BASELINE ARRA Y (CLBA)ROOM 167Chairman: J.M. MacLeod

13:30FF1 The Impact of a Continental Array on Current Problems in Radioastrophysics

E.R. Seaquist, V ip a A tm in t o i kAtAonomy, U n lv e M tty Ojj Toronto

14:00FF2 The CLBA and A National Research Program in Geodesy and Geophysics

W. Cannon, V ip a A tm in t oá TaAth and A tm o6pkvU c Science, VoAk UnLvoAAÀty

14:30 Open discussion on CLBA

WEDNESDAY, JUNE 29,1983 PAR TICLE PHYSICS IIROOM 160 Chairman: E. Vogt

13:00FG1 OPAL at LEP: A New High Energy Physics Experiment

Presented by R.K. Carnegie, C a A tito n UntVQAAity

13:30FG2 Canadian Participation in HERA

Presented by J. Martin, IPP S d i i n t l A t , U n iveA A tty 0& TOAOnto

14:10FG3 New Results on b quarks for the ARGUS Collaboration

Presented by J.D. Prentice, U n iveA A tty Ojj TOAOntO

15:00FG4 TRIUMF Kaon Factory Plans

Presented by E.W. Blackmore, TPÍUMF

69

WEDNESDAY, JUNE 29, 1983 ROOMModerator: H.E. Petch

PHYSICS AND SOCIETY

16:00FH1 Manpower for R&D in the 80's

Panellists:

Allan I . CarswellVoak Univetiity and Opt&ch Incotvpoaatzd Paul A. RedheadNational Rueatch Council o& CanadaStuart L. Smith S c i e n c e Council o(, CanadaGordon M. MacNabbNatuAal S c i e n c e s and Engineeting Reieaach Council

17:00 Discussion

WEDNESDAY, JUNE 29, 1983 ROOM 167 Chairman: J.E. Hesser

19:00 Open Discussion on STARLAB

WEDNESDAY, JUNE 29, 1983 ROOM 060

21:00 CAP COUNCIL

Chairman: B.P. Stoicheff

70

Author Index/Index des auteurs

AASHAMAR, K . . BD3 ABEGG, R.i DKG, DL9,

DL1G, DL1B ABEL. G . . DLB ADAIR. H.L.. DG3 ADAM. M.J.. DF2 ADAMIDES. E . . DL3 ADAMSON-SHARPE. K.M . . BC1 ADELBERGER. E.G.. AG2 AERS. G.. BB7 AFFINITO. J . . BA1 AHLBORN. B . . DH21. DH2A,

DH25 -AITHAL. S . . BJ3 AL-SHIRAIDA, Y.S., DH2,

DH3ALBERDING. N . , BKA ALEXANDER, T.K., DK2 ALFHE1M, A., DHA ALI, N., DC3, DCA ALOUSI, A., DK3 ALSTER, J., D K 5 , DL15 ALTMAN, A., DL15 AMIRANOFF, F . , DH12 ANDERSON, A., BD12, DDG,

DD7 'ANDERSON, H.L., BK11,

DJI 2ANDREWS, B . , DDG, DD7 ANIOL, K.A., BD 2 A , DJ5.

DL15, DL 19ANSALDO, E.J., BC3, BCA ANSBACHER, W . , BD5 ANTIPPA, A.F., BH1A ARMSTRONG, R.L., DD1 ARSENEAU, D.J., BD20,

BD21, BD22, BD23 ARVIEUX, J., DL 1Θ ASHERY, D., DL 15 ASTBURY, A., CBA AUCIELLO, 0., CGI AULD, E.G., DJ9, DJ10,

DJ11, DL12, D L 13 AVELEDO, C.E., BDA AXEN, D.A., DJ7 AZIZ, R.A., BD19 AZUELOS, G., B K 1 1 1 DJ12,

DL 1AAZUMA, R.E., DKG, DLG

BAARTMAN, R . , BKB BAER, H., D L 1A BAGHERI, A., DL19 BAHR, J.L., BD5 BAIRD, D.C., BJ1 BALLENT I NE, L.E., BBG BARDHAN, K.K., BAB BARIBEAU, J.-M., BE2 BARNARD, A.J., DHA BARNETT, B. M . , D K 5 , DL15,

DL 17BARRIE, L.A., BG1 BATTEN, A.H., DA15 BAYLIS, W.E., BD1 BECKER, K., BD1A BEDFORD, R.E., BJA BELANGER, P.A., BFG BELL, M.B., BH7 BELL, R.A., BH19 BERGERSEN, B . , BAG BERLINSKY, A-.T-, AE1 BERNARD, J.E., D H 5 , DHG,

FD2BEROLO, 0., DE3 BERTRAND, L . , BJ3, B K 16 BHAGERI, A., BD2A BINBREK, O.S., DD7 BIRCHALL, J., DL 16

BIRD, R. T.F., BK2 BLACKMORE, E.W., DC 12,

D L 17, FGA 'BLECHER, M . , BK11, DJ12 BLOK, H.P., BJ5 BOAL, D.H., AB3, DKG BONYUET-LEE, D . , BDA BOOTH, I.J., DC10 BOSE, S.K., BBG BOTELER, J.M., DC9 BOTMAN, J.I.M., BK9 BOUCHER, C. , DLB BOURBONNAIS, C. , DEI A BOURBONNAIS, L. , DE3 BRACCO, A . , DL9 BREBNER, J.L., DDB, DE11 BRETT, M.J., BA1 BREWER, J.H., BC3, BCA, BC5 '

BRICAULT, P.> DLA BRION, C.E., BD16, BD17 BRODEUR, P., DH9, FDA B RODIE, D.E., BA2, BAA,

R K 1 B 'BRODOVITCH, J.-C., BC1,

BCGBROOKS, R.L., BD9 BROTEN, N.W., BHA BROUDE, C., DKG BROUWER, P., BK10 BRYMAN, D. A . , BK11, DJ12, D L 1A , FC2

BUCHINGER, F . , AF2 BUCKMASTER, H.A., B B A ,

DC9BUGG, D.V., DJ7 BURBANK, M.B., AH1 BURGERJON, J.J., BKG BURNETT, N. H . , D H 7 , FD1 BURNHAM, R.A., BK11,

DJI2, DL 1 A ■BUYERS, W.J.L., BCB, BC9

CAILLE, A., BA 5 , DCG CAIRNS, E.B., DL 16 CAMERON, J.A., CDI. DL5 CAMERON, J.M., DL9, DL 1B CAMPBELL, E.C., DAI A CAMPBELL, E.M., AD2 CANNON, R.D., BH19 CANNON, W., FF2 CAPJACK, C.E., DH16 CARETTE, J.-D., BE2 CARNEGIE, R.K., FG1 CARON, L.G., DEI A CARSWELL, A. I - · FH1 CAKItH, rt.u.t B K 11, DJI2 CASWELL, J.L., DA7 CELLIERS, P . , DH10 CHAKER, M., DH20 CHAN, B.W., DCB CHAN, K.C.D., BK2 CHAPLIN, D., DF5 CHAPMAN, D., FAI CHATTERJEE, M.B., DK 1 CHEHAB, S . , DCB CHEUNG, C.Y., DKB CHIN, S.L., BFA, BF5 CLARK, J.L., D L 10 CLOUTER, M.J., BBB COLBOW, K., DEI COLERIDGE, P.T., DC7 COMYN, M., DJ7 CONZETT, H.E., D L 16 COOMBES, H . , DL16 COOPER, M., D L 1A CORMIER, M., BF3 COSTAIN, C.H., BH12

COTE, R., DCG COUVERT, P. , DL 11 CRADDOCK, M.K., B K 7 , BK9 CROOKS, M.J., DG1 CROWE, K., BC3 CROZIER, E.D., BKA CUJEC. B . , DL7 CURZON, F.L., DH23

D ’AURIA, J.M., DKG, DL10 DAGG, I.R., BD12 DAHN, J.R., AA3 DALGARNO, A . , CCI DANIELSON, L . , BE3 DASMAHAPATRA, B . , DL7 DATARS, W.R., BA9, DE12 DAUNT, J.G. , BJ1 DAUTET, H., DKA DAUTOVICH, D.P. , CF2 DAVIEL, S., BD16 DAVIES, C.A . , DL1B DAVIES, J.A., BEA, BE5 DAVIS, C.A., DL1G DAVIS, J.H., FA3 DAVISON, N.E., DL1G DE TAKACSY, N., DL21 DE VERTEUIL, F . , BB1 DECOSTE, R. , D H 1 1, DH12 DELANEY, P.A., BH22 DELWICHE, J., BD15 DEMILLE, G.R., BC7 DEPOMMIER, P., BKll,

DJ 12, D L ΙΑDESMARAIS, D . , DG3, DGA DEWDNEY, P.E., BH9, BH13 DHARMA-WARDANA, C . , ΒΒ7 DICKINSON, D . F ., DAS DIXIT, M.S., BKll, CB2,

DJ 12, D L 1A DOMBSKY, Μ . , D L 10 DOMItK, C., D H 15 DONOFRIO, T., DC1 DOUGLAS, B . , DF5 DRAKE, T.E., CEI, D K 5 ,

DL 17DUGGAN, J.L., DG3, DGA DUNLAP, R. A., DF3 DURAND, D . , DAA

EDER, W.E., BJ1 EDGINGTON, J.A., DJ7 EGELSTAFF, P.A., EA2 ELLIS, S., CB3 ELLIS, T.H., BE3 ENDO, Y . , BH7 ENRIGHT, G.D., D H 7 , FD1 ENTEZAMI, F., BC2, BD 2 A ,

RD25, DJ7EPSTEIN, M.B., DL9 ERDMAN, K.L., DL17 ESCUDERO, R., D D 1 1 EVANS, E.A., FA2 EVANS, H.C., DK2 EVERETT, A.E., BH1A

FAHLAMN, G.G., BH2, DA1 FALK, W.R., DJ9, DJ10,

DJ 11, DL12, D L 13 FARKAS, G., BFA, BF5 FAWCETT, E., DC2, DC7 FEARING, H.W., DL23 FEDOSEJEVS, R., DH15, FD3 FELDMAN, J.L., BA7 FELDMAN, P.A., BH 7 , DAG FIFE, A.A., BJ2 F ILL ION, A., DE2 FISHER, W. A . , D A 15 FITZGERALD, M.P., BH1G

FJARLIE, E.J., DG2 FLEMING, D.G., BC5, BD20, BD21, BD22, BD23, CD2

FLETCHER·. J.M., DA15 FLETCHER·. R., DEB FOGLEMANi G., DJA FORGÁCS, C. , FE2 FORTIN, ΙΞ. , DE3 FRANUS-MUIR, E., DC2 FRINDT, R.F., AAI FRY, C.A., DJG

GAGNON, Y., BK1 GAILY, T.D., B D 10 GAIZAUSKAS, V., BH2G GALARNEAU, P., BFA, BF5 GALT, J.A., BH12 GARNER, D.M., BC2, BD20, BD21 1 IÎD22. BD23

GELBART, W . , DF2 GELBART, Z., BKG GELFANDEEIN, V., DE2 GEORGALLOS, A., FAA GILES, G.., D.I9, DJ 10,

DJ 11 1 DL12, D L 13 GILES, R., DH1 GILL, D.R., DL15, DL17 GILLESPIE, R.J., ΠΕ12 GIROUARI), F.E., BA3 GIROUX, J., BK1 GLAUDE, V., DH20 GOBEIL, G., DLB GOODMAN. G., DF5 GOORVITCH, D . , DA13 GORMEZANO, C . , DH22 GOTOW, K . , BKll, DJ 12 GOWER, A . , CH3 GRAHAM, D., DF 1 GRAY, D.F., DA9 GREEN, P., DL 1 G GREEN, R.E.L., DKG GREENIAUS, L.G., DL9,

DL 1GGREGORY, B.C., DH22 GREGORY, P.C., BH1, BH2 GREYTAK, T.J., AE2 GRIFFIN, A., DC5 GRIFFITHS, K., BEA, BE5 GRINDLAY, J., b k ?7 GUBLER, H.P., DL9, DL15, DL1A

GUILLOM, F., DD9 GYAPONCi, G. J., BC7 GYLES, W . , D K 5 , DL15,

DL17

HA A S Z , A . A . , CGI HAMMERI5ERG, J.E., BBG HANES, D.A., BH1B HARDY, E., DAA HARDY, J.C., AGI HARGROVt, ■ K ■ , BK 11,DJ 12, D L 1A

HARRIS, G.L.H., BH1G,BH17 ; BH19, DA2

HARRIS, H.C., B H 1 7 , DA2 HARRIS, W.E., BH1B, DA2 HARRIS-LOWE, R.F., BK17 HARRISON, J.P., DD9, DD10 HARRISON, R., DF5 HARSHMAN, D . R . , BC3, BCA HASELL, D.K., DL9 HASINOFF, M.D., B D 2 A . BKll,

DJ5, DJ 12, D L 1 A 1 DL19 HAYNEE, R.F., DA7 HEALEY, D., DJ7 HELMER, R. , DKG HERZBE RG, G. , BH7

71HESS. W.R.i DH22 HESSER. J.E.. AC2. BH17. BH19. BH20

HETHERINGTON. D.W., DK3 HIGGS. L. A . , BH10 HILKO. B . . D H 5 . DHé>, FD2 HILL. G.. DAI 5 HI OB. E . 1 DHA HÍRŐSE. A., CG2. DH1B HI ROTA, E., BH7 HO, N.S., DFA HOFF. R.M., BG1 HOLDSWORTH, D. , BK13 HOLT, R.A. , BD10HOMMA, Y.. , DF2HORVATH, D . , B D 2 4 1 BD25

DJ5HOUTMAN, H., D H 5 , DHé>,

FD7HU, C. Y., BC3HUBER, K. P., BDBHUBIN-FRANSKIN, M.-J.,

BD15HUNT, J.L., BD9, DA13 HUSSEIN, A., DL1B HUTCHEON, D.A., B K 5 , DL9,

DL1B, FC1HUTSON, J.M., BD1B HUTT, D., DF3

IAFIGLIOLA, R . , DKA INGALLS, R., BKA IRWIN, J.C., B A 7 , BAB,

BA1 0

JACKLE, G., BA 10JACKMAN, J. A., BCB, BC9JACKMAN, T.E., BEA, BE 5JACKSON, K. P., DKé>JACQUES, C. , BDé>JAMES, C • R., DH lé>JAN, N . , BB1JANZEN, V.P., DL5JENNINGS , B.K., DJ3i1 DL21JERICHO, M.H., BA5JEWISON, M.S., DA 1 0J IVAN, S . , DF 2JOHNSON, R. R., D K 5 , DL 1 1,

DL 15, DL 17 JOHNSTON, HON. D.J. JOHNSTON, T.W., DHB,

DH13, DH1AJOHNSTONE, I.P., DK2 JOHO, W., BK7 JONES, G . , DJ9, D J 10,

DJ11, DL 12, DL13 JONSSON, Η., BE3 JOOS, B . , BA6

LABRIE, J.-P., B K 1A LABRIE, R., BK1 LACHAMBRE, J.-L., DH11 LAHLOU, F . , DL7 LAM, G . , DF5LAMARCHE, G. , DC 1, DCBLAMEDA, L.A. , BDALANDECKER, T . L. , BH 10,

BH11, BH13LANDSTREET, J.D. , DA 10LAPOINTE, R. , BK 1LAVIGNE, P., BF2, DH 12LAXDAL, R., BK 7 , BKBLEBLANC, M.A.R. , DD12 LECLAIR, G., DH9 LECLERC, B . , BD15 LEDOYEN, F., BF3 L E E , D. Μ. , AE3 LEE, J.K.P., DKA LEE, R., BKB LEE, W.P., DL9, DL16 LEECH, J.W., DD íj LEES, R.M. , BD13 LEGAULT, J.P., BK11 LEIBBRANDT, G . , CA1 LEIT CH, M . , DJ 12, DL 1 A LEITCH, M.J., BK11 LENZ, J., BKé>LEPINE, Y . , B A 5 , DE 11 LESLIE, J.R., DK2, DL3 LESSARD, L., DK3 LEUNG. K.T., BD17 LEUNG, S., BC6 LEVINSON, S . , DL15 LICHTENSTADT, J., DL15 LIVESEY, D.L., BC7 LLEWELLYN, E.J., ACA LO, W.F., BH13 LOEWEN, S . , D H 2 A , DH25 LOLOS, G.J., DJ9, DJ10,

DJ11, D K 5 , DL11, DL12, DL 13

LOOKMAN, T., BB1 LORRAIN, J.P., DD12 LORRAINE, P. , DL 11 LUDGATE, C. , DF5 LUDGATE, G.A., DJé>, DJ7 LUKE, T.M., BD3

MA, C.K., BJA MACDONALD, A.H., DD5 MACDONALD, J.A., BK11,

DJ12, DL 1 AMACDONALD, J.R., BD9 MACKENZIE, G.Η., B K 7 , BKB MACKINTOSH, A., DEI MACLATCHY, C.S., DH17 MACLEOD, J.M., BHA, CC3 MAFNABB, G.M., FHA

KAKULE, F., BB2, BB3 KALLIN, C., DE9 KASTNER, S.O., BD2 KAY, D . , DJ2 KEITEL, R., BCAKENNEDY, J.F. , DA 11KENNETT, T. J. , DL1KENNING, G. , DE7KERNAHAN·. J. A . , BD5KEROACK, D. , DE 1 1KESSLER, D. , BK 11, ]KIEFFER, J.C. , DH 12KIEFL, R., F. , DJ 6KIEFTE, H., BBB KIESER, W.E., BK3 KIM, S.M., BCB, BC9 KING, J.D., DLé>KI RCZENOW, G., AA2 KIVELSON, S.A., CA3 KLEIN, M.J., DA5 KNYSTAUTAS, E.J., BD6 KOPAC, J.A., DL20 KORNELSEN, R . , DF5 KORTELING, R.G., DKé> KOST, C.J., BK9 KUIPER, E.N.R., BHB KUIPER, Γ.Β.Η., BH1B KUNDU, M. R. , BH2é> KWAN, J.< DH 10 KWOK, S . , BH3, DA6

PlALIAVlbH, J.C., tsB5 MADORE, B.F., BH2A MAK, H.-B., DK2 MALGHANI, M.S., BD13 MALHOTRA, V . M . , DC9 MANCHESTER, R.N. , BHé> MANOOGIAN, A., DC 1, DCB MARCHAND, R . , DHlé> MARCHILDON, L., B H 1A MARGAZIOTIS, D.J., DL9 MARSHALL, G.M., DJé> MARTIN, F., DH1A MARTIN, J., FG2 MARTIN, J.-P., BK11 MARTIN, S., DL17 MATHIE, E.L., DK5 MATTE, J.P., DH12 MATTHEWS, H.E., BH7 MATTHEWS, J.M., BH21 MAXWELL, O.V., DJI, DL22 MCALARY, C.W., BH2A MCAVOY, G . , BBA MCCARTHY, N . , BF2 MCCLURE, R.D. , BH20 MCCONKEY, J.W., BD1A MCCONNELL, J.C., CCA MCCUTCHEON, W.H. , BHé. MCDADE, I.C., ACAMCDONALD, W.J., DLlé> MCGEER, P., DM1

MCGONEGAL, R . , BH2A MCINTOSH, G. , DH5, DHé>,

FD2MCKEE, J.S.C., CE2 MCKEE, R.J., BK11, DJ 12 MCKELLAR, A.R.W., BD1 1 MCKEN, D.C.D. , DH15, FD3 MCKENNA, J . , DL11 MCKEON, D.G.C., AB2 MCKEOWN, J. , BK2, B K 1A MCKINNON, W.R., AA3 MCLAREN, R.A., BH2A MCLATCHIE, W . , DK2, DL3 MCMAHON, R. , BA 1 MCMULLAN, W.G., BA7 MCPARLAND, B.J., DJ9,

DJ 10, DL 12 MEASDAY, D. F ., BC2, BD 24,

DL 19MEENAKSHI, P., MENGEL, Μ . , BE3

BD5

MES, H., BK11, DJ 12, DL14MEYER, J . , DH5, DH6, FD2 MIKULA, R.J., BD21 MILLER, C . A . , B K 5 , DKé>,

DL9, DL 16, DL 1 B MILLWARD, C.G., DA12 MILNE, A., D H 2 1 MI TARI, O., CG2 MITCHEL, G.R., DHB, DH1A MIZIA, J., BD27 MOINESTER, M . A . , DL 1A ,

DL15MOORE, C.J. , B A A , B K 1BMOORE, R.B. , DK3MOREAU, J.- P. , BDé>MORGAN, K., DE 1 2MÓRRA, R.M. , DD1MORRIS, D. , BK 12MORRIS, S., BH23MORRISON, S .R., BEIMOSS, G. A. , DL9, DL 1 é>,

DL1BMUIR, C. , DC7 MYERS, R., DL11

NACHABE, M., DLA NAGLER, S.E., CA2 NAVON, I., BK11, DJI 2 ,

DL 1 ANEWMAN, K.E., BC1, BCé> NG, A., DH2, DH10 NG, H.K., FBI NINKOV, Z., DA3 NOIRHOMME, B . , DE2 NORTON, P.R., BEA, BE 5 NUEGEBAUER, G . , BH2A NUMAO, T . , BK11, uJl2,

DL1 A

O ’BRIEN, R.N., FE2 OFFENBERGER, A.A., D H 1 ,

DH2, DH3, DH15, FD3 OLIN, A., DJé>, DL 1A OLSER, W.C., DL1B ORAM, C.J., DJ6 OTIS, G., BF1 OTTEWELL, D . , DJ9, DJ10 OVENDEN, M.W., CH2

PAGE, J.H., DD2 PALCIC, B . , DF5 PARE, C. , BFé>PARSONS, R .R., BAIPARTHASARATHY, R., DJ2PASI N I , D. , DH10PATE, B.D. , AH2, DF 2PAUL, D.A.IL . , BD2é>, BK 12

BK 13PEARSON, j .B., DH23PEEL, S.J. , BD1PEEMOELLER , H . , BB2 , BB3PENNEY, R. , BBBPEPIN, H., ADI, DHB ,

DH12, DH 1 APERCIVAL, 1P.W., BC1 , BC6PERCY, J.R ., BH25PERLMAN, M . M., D E 2PERZ, J.M. , DC7

PETERSON, D.T., BCB PICARD, G . , DH13 PICHE, Μ. , BFé>PINARD, A., BA3 PINDOR, A. J . , DC5 PINEAULT, S . , DAB PINK, D.A., B B 1 , FAA PINNINGTON, E.H., BD5 PINTAR, M.M., BB 5 , FB3 PLATTNER, G.R., DL 16 PLAVEC, M.J., EA3 PLUMER, M.I., DC2, DC11 PLUZHNIKOV, V., DC2 POFFENBERGER, P.R., DL16 POLL, J.D. , BD9, DA 13 POPIL, R. , D H 5 , DHé>, FD2 PORKOLÁB, M., CFI POSTMA, H., DL9 POTVIN, L., DLA POULIOT, J., DLA POULIOT, L., BK 1 POUTISSOU, J.-M., B K 11,

DJ 12, DL 1 A , DL 19 POUTISSOU, R., B K 11, DJ12,

DL1 APRENTICE, J . D . , FG3 PRESTWICH, W.V., DL 1 PRUNEAU, C., DK 1 PURTON, C.R., DAé>

RANGACHARYULU, C. , DK 1 READ, L.A.A. , BD12 REDDY, S.P., BD7 REDHEAD, P.A., FH2 REEVES, E.M., AC1 RICHARDSON, H., AC3 RICHARDSON, J.R., BK 7 ,

BK9RICHER, H.B., DA1 ROBERTSON, B . , CH1 ROBERTSON, B.C., BD2A,

D J 5 , DL 19ROBERTSON, L.P., DB1 ROBERTSON, R., DF 1 ROBINSON, B. J., BHé> ROBINSON, M.C., BDA ROGER, R.S., BH9 ROLFS, C. , DLé>ROSENBLUM, S.S., BC3 ROSENFELD, A.Μ . , DE 13 ROSER, H.W., BD 2 A , DJ 5 ,

D K 5 , DL15, DL 17 ROSNER, S.D., BD10 ROSS, G.G., DLB ROSTOKÉR, G . , CHA ROUSSET, G., BJ3, BKlé. ROUTLEDGE, D . , BH13 ROY, D . , BD15 ROY, G., DL9, DL 16, DL1B ROY, R., DLAROZMUS, W.■1 DH3RUDAZ, S. , CB 1RUTH, T., DL10RUTH, T.J.i. DF 2RUTHERFORD', A.R., :DD10

SABBAGH, J,., DH1ASACHRAJDA, A. , DD9SAINTONGE, G., DDBSA I ΤΟ, S., BH7SALOMON, M ., BD2A, BK 10

DL 19SANTHANAM, K. S. V. , FE3SAWAFTA, R.I., DL2SCARFE, C.D., BH22 SCHLATTER, P., B K 11, DJ12,

DL 1 ASCHLOESSIN, H . H . , DDA SCHMAHL, E.J., BH2é>SCHMOR, P.W., DJ6 SCHRAM, D.C., DH9 SCHREINER, L.J., BB5 SCHUBANK, R.B., DL5 SCHULZ, Μ. , BD26 SCHWARTZ, C. , BD1B SCHWERDTFEGER, C.F., DC10 SCOLES, G., BE3 SEAQUIST, E.R., FF 1 SFARS, W.M., BEI

72

SEARY 1 A. J., BK4 SELENi M.i BD9 SENBAi M.i BC4, BC5, BD20, BD21, BD22, BD23

SHARPi A.R., BB2, BB3 SHEFFER. G.i DL10 SHERIFi H.S., DL2 SHINE, R.A., BH26 SHRIMPTON, N.D., BA6 SHYPIT, R.L.i DJ7 SIMPSON, A.M., BA5 SINGERí M.i DJB SINHAi B.K.i DL4 SKARSGARDi H.M.i CG2 SKARSGARDi L.i DF5 SKENSVED, P.1 DK2i DL3 SLOBODRIANi R.J.i BKli DL 4

SMITHi H.J.T.i DD11 SMITHi S.L.i FH3 SMITHi S.R.P.i DD2 SOBIEi R.J.i DK5, DL 151 DL 17

SOUKUPi J.i DL 16 SPADINGERi I.i DL11 SPENCERi D.P.1 BC5 SPRENGERi Η.Ρ.ι BK6 SPULLERi J.1 BKlli DJ12i DL 14

ST. PIERRE1 C.i DK1 ST ADLBAUERi J.i BD24 STANGEBYi P.C.i CGI STANISLAUSi S.i BC2 STARTSEV, V.E., DC7 STEINERi T.i DE5 STEINITZi M.0.1 DD3 STENTONi D.E.i DB1 STETZi A.W.i DL9

STEVENSON, N.R.i DJ7 STINSONi G.M.i BK5i DL16 STONE 1 N.W.B., BD12 STOTTi M.J.i DD10i DE13 STROINKi G.1 DF3 STROM-OLSENi J.O.i FB2 SULLIVAN, H.M.i BG3 SVENNE, J.P.i DL 16 SWANSON, P.N.i DA5 SYMONDSi G.R.i BH21 SZOGHYi I.M.i AF1

TACIKi R.i DK51 DL 151 DL 17

TALMANi J.D.i BD3 TARASENKOi V.V., DC11 TATUMi J.B., DA14 TAYLORi A. R. 1 BH1 TAYLORi D.R.i DDli DD2 TAYLORi R.i BB7i DD5 TAYLORi R.B.i DL 12 TEHi C.K.i DE 4 TE ICHMANNi J.i DH19i DH20 TEMPLETON1 I.M.i DC7 TENGi L.C.i BK7 TERREAULTi B.i DL8 THEWALT1 M.L.W.i DE5i DE6 TIMUSKi T.i FBI T I Ni C.C.I DE 10 TINDALLi D.A.i DD3 TIPPINGi R.H.i DA13 TOMASZEWSKIi L.A.i DA10 TOMOV, I.V., DH15 TORRIEi B.H.! DD6i DD7 TRAUTVETTER, H.P.i DL6 TREVENA, I.i DF1 TRUONGi V.V., BA3 TSAI 1 J.-S.i DL 1

TURKINGTONi R.R.ι BK17 TURNBULLi D.N.i B62 TURNERi B. i CC2 TURNERi D.G.i BH15 TURNERi E.i BD22 TURNERi R.i BK18

UMMATi P.ι BA9 UNRUHi W.G., ΑΒ4ι EA1

VALBUSA, U.ι BE3 VALLEEι J.P.i ΒΗ4ι BH5 VAN ANDELi H.W.H.i DH9i FD4

VAN DEN BERGHi S.ι BH17 VAN HEERDENi I.i DL 18 VAN NŐSTRANDi E. i BD7 VAN OERSi W.T.H.i DL9i DL 16

VAN MlJNGAARDENi W.i BD14 VANELDIKi J.F.i BH13 VEITi E.A.i DJ3 VENTOi V.i DJ 1 VINCENTι D.ι BF1 VINCENTι J.i DL 15 VIRTUEi C.J.i BD24i DJ5 VISEi J.B.ι DL6 VISWANATHAN, K.S.i DJ2i

DJ4i DJBVOGTi E.W., DL20 VON SACKENi U.i BA2 VRBAi J.i BK15

WADDINGTONi J.C.i BD9i DL5 WAITi G.E.i DJ7 WALDEN, P.L., DJ9i DJ10i DL 12, DL 13

WALDEN, P.W., DJ 11

WALKER, G.A.H., D A 12WALLACE, J., BB2WALTHAM, C.E., DJ7WARD, T. E . , DL 10UARRFN, J . B . , DJ6WATKINS, S.P., DE6WEARE, J . , BE3WEHLAU, W.H. , BH21WE ICHMAN , F.L., DE 4 , DE 11WELCH, D .L., BH24, BH25WESSEL, S., DEIWHITEOAK , J.B., BH6WIEDERICK, H.D., BJ1WIEDNER, C., D K 5 , DL 17WIELAND, F., BH24WOLOSHYN , R.M., DK8WOODGATE , B.E., BH26WOODS, S .B., DG3, DC4WOOLLEY, J.C., DC1, DCBWORKMAN, R.L., DL23WORT IS, Μ., AB1WRIGHT, C.S., BK11, DJI 2WRIGHT, L.E., DK7WRIGHT, L.S., BJ1

XING-XIAO, M., BF5XU, S.W. , DK4

YAVIN, A. , DL10YERGEAU, F., BF4, BF5

ZALESKI , Η . , BA9ZAREMBA, E . , DE7ZIEGLER, W. , DJ9, DJ 10,

DJ 111 DL 12, DL 13 ZIMMERMAN, P., DA5 ZUCKERMANN, M.J., BB1

UNIVERSITY OF GUELPH

VAN DE GRAAFF ACCELERATOR LABORATORY

Applications are invited for a new research/ technical position in this laboratory which provides ion beam analysis to a diverse group of scientists. Duties include specimen preparation, accelerator operation and data recording. Experience in PIXE or RBS analysis is desirable and fam ilia rity w ith radiation detectors and accelerators necessary. Graduates at B.Sc. level or higher may apply; salary w ill reflect experience. Full details from

Professor J.L. Cam pbell,Physics D epartm ent,U n ivers ity o f Guelph,Guelph, Ontario,Canada, N1G W 21.

In accordance w ith Canadian Immigration require­ments th is advertisement is directed to Canadian citizens and permanent residents.

POSTDOCTORAL FELLOWSHIPIN

PLASMA PHYSICS

Applications are invited for postdoctoral fe llow ­ships in the Plasma Physics Laboratory, University of Saskatchewan. Two openings are available for experimentalists to work on:

Plasma heating studies w ith the STOR-IM tokamak.

Construction of the STOR-M tokamak and preparation of diagnostics.

Ion wave experiments.

Send curricu lum vitae, including names of three references to:

Dr. H .M . Skarsgard Physics D epartm ent U niversity o f Saskatchewan Saskatoon, Saskatchewan S7N 0W 0

lirO unces

30 YEARS SUCCESSin anticipating and meeting the experimental and routine requirements of scientists worldwide is the proud record of the Nuclear Enterprises Scintillator Group.

Unsurpassed Scintillator “know how” combined with excellent research and production facilities enables the Company to offer a range of plastic and liquid scintillators unrivalled in efficiency, size, transparency and speed. This includes world- renowned Plastic Scintillators NE102A, NE110 and Pilot U; an extensive selection of unloaded and loaded liquid scintillators and particle detectors; and a comprehensive range of inorganic crystal scintillators and demountable assemblies.

Full details on request.

mNUCLEARENTERPRISESLIMITED.

▼ s Technical Marketing Associates LimitedHead Office: 6620 K itim at Road. U nit 6. M ississauga. O ntario L5N 2B8 Telephone: (416) 826-7752

PHYSICSFACULTY POSITION

CONDENSED MATTER PHYSICS

RESEARCH POSITIONS

Applications are invited for positions in the following areas: nuclear physics: Van de Graaff laboratory, nuclear structure theory and experiment, nuclear astrophysics, applications of nuclear techniques. Solid state and applied physics: development of magnetometers for gas pipeline inspection, effects of stress on the magnetisation of steels, nuclear magnetic and quadrupole resonance, solid state theory, fast ion transport, surface diffusion, thin films and ferroelectrics, physics at millikelvin temper­atures, phase transitions, positron annihilation in solids, metals at high magnetic fields, ultrasonics. Astronom y and astrophysics: galactic structure and evolution, general relativity, relativistic astrophysics, stellar struc­ture and evolution, star formation and the interstellar medium. Candidates of either sex are equally encouraged to apply. Salary dependent on qualifications.

Please apply, enclosing a curriculum vitae and the names of three referees to:

Dr. M.F. S tott. Head,Department o f Physics,Queen's University,Kingston, Ont. K7L 3N6

Applications are invited for a tenure-track faculty position in the Department of Physics, Memorial University of Newfoundland, subject to final budget­ary approval. A t present, the research of the Department is prim arily focussed on atomic and molecular physics including studies of low tem per­ature molecular solids. As part of the expansion planned for the Department, we are seeking one or more individuals to further develop an outstanding research program in either experimental or theoret­ical condensed matter physics. The successful candidate w ill be expected to teach courses at both the graduate and undergraduate levels. Salary and rank w ill depend on qualifications. Applications, including a curriculum vitae and the names and addresses of three referees should be forwarded as soon as possible to:

Dr. D.H. Rendeli, A c ting Head D epartm ent o f Physics Memorial University o f Newfoundland St. John 's , N fld . A1I3 3X 7

In accordance w ith Canadian immigration policy, this advertisement is directed in the first instance to Canadian citizens and permanent residents of Canada.

A pp lica tions are invited from physic is ts w ith demonstrated experience in the instrum entation and apparatus of experimental high energy physics and ability to handle on-line and off-line analysis programs. M in im um academic level is a Ph D. or equivalent in nuclear science. The successful appli­cant w ill be expected to work at McGill University in Montreal and at DESY, Hamburg, West Germany. Initial appointment w ill be for two years. Closing date for applications is May 15, 1983. In accordance w ith Canadian im m ig ra tion requirem ents, th is advertisement is directed to Canadian citizens and perm anent res idents of Canada. A pp lication: curricu lum vitae w ith names of tw o referees to.

P.M. Patel Physics D epartm ent M cG ill U n iversity 3 6 0 0 U n ivers ity S tree t M ontrea l, P O. H3A 2T8 Canada

SENIOR VISITING FELLOWSHIP PROGRAM

Centre for Interdisciplinary Studies in Chemical Physics

The University of Western Ontario London, Canada

The Centre for Chemical Physics invites applica­tions for its Senior V isiting Fellowship Program from established scientists carrying out research in areas that bridge two or more of the disciplines of app lied m a them a tics , phys ics , ch e m is try , engineering, botany, nuclear medicine and radia­tion oncology. The Fellowships are tenable for a period of up to 1 year, and provide funds for travel and partial or complete living support at U.W.O. During the tenure of their Fellowships, visitors w ill be expected to work in conjunction w ith Centre members.

For additional inform ation and application form please w rite to:

Chairm an, C om m ittee on V is iting Fellows

Centre fo r In te rd isc ip lina ry S tudies in C hem ical Physics

The U n ivers ity o f W estern O ntario London, O ntario , Canada N 6A 3K 7

Applications for 1 9 8 4 /8 5 must be received before August 31, 1983.

t 9 SK TMA PhysicsOptical Radiation Measurements VUV, UV-Visible (0.3 to 2.2-Meter Focal Optical and mechanical modules for custom

Length) Monochromators and Spectrographs measuring and positioning assemblies

Gamma Scientific's Systems Have Generated More Solutions for Accurate and Repeated Results.Look at Gamma Scientific’s all new optical radiation measuring products; digital radi­ometers, high purity monochromators, new generation photomultiplier and silicon detec­tors, ultra stable calibrated sources.Add the high performance of Computer/Con- troller and you've got a system that produces analyzed data within seconds of acquisition, all under control of Gamma Scientific’s copyrighted SPECTRL"* and SPATL'“ Soft­ware.

Model 247Monochromator/Spectrograph Grazing Incidence 2.2-Meter 1-250nm

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Model 2051Czerny-Turner with Corrected Optics 1.0-Meter . .185-26,OOOnm SNAP-IN GRATING U.S. PATENT #3,433,557 — · - ·

Model EU-700Czerny-Turner with Corrected Optics 0.5-Meter 185-4,OOOnm

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S C H Q E F F E L /IB c P H E B S n n . I N S T R U M E N T

A wide line of basic optical instruments, plus scores of Gaertner interchangeable compo­nents and accessories enable you to build your own precision optical system. There’s an ideal combination to solve almost any lab measuring, positioning, or observing prob­lem quickly and easily. Our Optical System Selection Chart tells you part of the story. Additional details on all the Gaertner optical instruments shown (plus many others) are contained in our Bulletin 161. Write for a copy of each, plus a General Index of litera­ture covering all Gaertner Instruments. Just ask for an Optical Measuring Information Kit.

M a n u fa c tu re rs o f metricin s t ru m e n ta t io n s in c e 1896

TMA Physics is a division of Technical Marketing Associates Limited

Head Office6620 Kitimat Road Unit 6Mississauga, Ontario L5N 2B8Telephone 416 826 7752 Telex # 06-218 227

HalifaxTelephone 902 429 4365

OttawaTelephone 613 226 8297

VancouverTelephone 604 270 8662

Postdoctoral Fellowship, Physics Dept., McGill University

COMPOUNDSEMICONDUCTOR

RESEARCH

Postdoctoral Fellow required w ith experimental experience in semiconductor physics and vacuum techniques. Duties include grow th by vapour phase epitaxy of GaAs and o ther com pound sem i­conducting m ateria ls, transpo rt m easurem ents and low temperature photoluminescence. Currently in use are a low pressure OMVPE equipment for crystal growth, variable temperature Hall coeffi­cient apparatus for transport properties, a Kr ion laser, double monochromator and photon counting equipment for optical studies. Send C.V. and two letters of recommendation to:

Prof. David Walsh,Physics D epartm ent,M cG ill U niversity,3 6 0 0 U n ivers ity S treet.M ontrea l, Quebec,Canada H 3A 2T8

UNIVERSITÉ LAVAL

POSTES D'ATTACHÉS DE RECHERCHE AU CRAM

Le Centre de Recherches sur les A tom es et les M olécules (CRAM) de l'U n ive rs ité Laval recherche des physiciens et des physico-ch im istes hautem ent qua lifiés (Ph D. avec une ou deux années de recherche pos t-d oc to ra t) spéc ia lisé s dans un des dom a ines su iva n ts : spectroscopie des états excités ou ionisés des atomes et des m o lécu les en phase gazeuse (processus c o llis io n n e ls e t /o u optiques), sp e c tro m é tr ie de m asse (aspects d ynam iques et s tructu re ls des ions), étude des biom olécules par spectroscopie, physique et ch im ie des interactions gaz-surface par des méthodes spectrom étriquesTout candidat choisi sera nom m é m em bre chercheur du CRAM pour une période de deux ans et devra soum ettre, avec l'appui de l'U n ivers ité , une demande de bourse d 'attaché de recherche (chercheur-bours ie r) un ive rs ita ire auprès du CRSNG avant le 1er novembre 1983. Par la su ite le renouve llem ent sera assujetti aux conditions du CRSNG.

Le salaire du m em bre chercheur du CRAM est établi selon les qua lifications, le m in im um étant $27 500 .00 par année. Une partic ipa tion à l'ense ignem ent est possible, selon les besoins du départem ent de ra ttachem ent e t conform ém ent aux norm es du CRSNGLes personnes in té ressées qui sont c ito yen s canad iens ou im m igrants reçus sont priées d 'envoyer, le plus tô t possible et au plus tard le 15 ju in 1983, un cu rricu lum vitae, une description de proje ts de recherche et de fa ire parven ir les noms de tro is répondants à :

M . Jan A . H erm an, d ire c te u r C entre de R echerches sur les A to m e s

et les M o lécu les (C R A M )Facu lté des Sciences et de Génie U nive rs ité Laval Québec, Qc. G 1K 7P 4 Canada

The University of British Columbia

RESEARCH ASSOCIATE IN LOW TEMPERATURE

PHYSICS AND MICROWAVE SPECTROSCOPY

A position is available for a Research Associate with demon­strated experience in low temperature physics, including the operation of dilution refrigerators, and in microwave spectro­scopy. Candidates should have at least two years post-doctoral experience, a good publication record, arid some teaching experience. This position will be largely unsupervised, and the applicant will be expected to initiate his own research in addition to assisting in the direction of research by giaduate students in the laboratory Therefore, the most important factor which we will consider when judging applicants for n is position is evi­dence that they can work independently and interact effectively with students The salary for this position will be in the range of $24,000 to $28,000 per year. The initial appointment w ill be for two years, subject to the continued availability of grant funding, and is renewable subject to satisfactory performance and con­tinued funding. Applicants should submit a resume and have three letters of reference sent by May 31, 1983, to: Profs W N Hardy and A.J. Berlinsky, Department of Physics, Univer­sity of British Columbia, Vancouver, B.C., Canada. V6T 2A6.The approximate starting date for this posit on is the Winter of 1983 or the Spring of 1984

In accordance with Canadian immigration requirements, this advertisement is directed to Canadian citizens and permanent residents.

DEPARTMENT OF PHYSICSQUEEN'S UNIVERSITY

A term renewable (tenure-track) appointment at the Assistant or Associate level w ill be available from September 1, 1983. Although preference w ill be given to candidates in astronomy or astrophysics, outstanding candidates in other areas are also encouraged to apply. The Department is active in research in the areas of astronomy and astrophysics, nuclear physics, condensed matter and low temperature physics, and applied and engineering physics.

Duties will include teaching and research. Salary nego­tiable: the current floors are: Assistant Professor $24,300 per annum. Associate Professor $31,600 per annum. Applications are invited until the position is filled.

Canadians and Landed Immigrants of Canada w ill be given preference in making this appointment and candi­dates of either sex are equally encouraged to apply.

A curriculum vitae and the names of three referees should be sent to:

Dr. M.J. Stott, Head,Department of Physics,Queen's University,Kingston, Ontario K7L 3IM6

Université d'Ottawa University of OttawaD é p a rte m e n t de P hys ique Phys ics D e p a rtm e n t

Le Département de Physique de l ’Université d'O ttawa annonce un poste vacant de professeur adjoint pouvant mener à la permanence à compter du 1er septembre 1983. La préférence pour le poste sera donnée à un candidat désireux d 'établir un programme de recherches de haute qualité en physique de la matière condensée. Il serait préférable que le candidat puisse dès le départ, enseigner en français et en anglais; autrem ent il devra s'engager à acquérir la compétence linguistique voulue avant la fin du contrat in itia l de deux ans. Le salaire m inim um pour un professeur adjoint est de $26,000. Les candidats sont invités à soumettre leur curricu lum vitae et les noms et adresses de trois répondants avant le 1et ju ille t 1983 au :

Dr. M arcel LeBlanc, D irecteur, D épartem ent de Physique,U niversité d 'O tta w a ,O ttaw a , O ntario K1N 9B4.

En conform ité avec les exigences de l'im m igration Canadienne, cette annonce s'adresse aux citoyens canadiens et aux résidents permanents.

The Physics Department at the University of Ottawa invites applications for a tenure-track appointment at the assistant professor rank starting September 1, 1983. Preference w ill be given to candidates who can establish a research program of high calibre in condensed matter physics. Candidates capable of lecturing in both offic ia l languages w ill be given preference; however, candidates comm itted to attaining th is proficiency before the end of the in itia l two-year appointm ent w ill also be considered. The salary floor for Assistant Professor is $26,000. Appli­cations w ith curricu lum vitae and names and addresses of three references should be forwarded before July 1, 1983 to:

Dr. M arcel LeBlanc, Chairm an, D epartm ent o f Physics,U niversity o f O ttaw a,O ttaw a, O ntario K1N 9B4.

In accordance w ith Canadian im m igration requirements th is advertisement is directed to Canadian citizens and permanent residents.

PHYSICIST

SCINTREX LTD., a sc ie n tific ins trum en ta tion manufacturer, is seeking a Ph D. level Physicist to form part of an R & D team working in the area of optical pumping and its applications for magnetic fie ld measurement.

Candidates must have 2 years industrial experience in related fields of physics, as well as a working knowledge of optics and electronics

We offer an attractive compensation package. Interested candidates are asked to send their resume in confidence to:

Personnel M anager SCINTREX2 2 2 S n ide rc ro ft Road C oncord, O ntario , Canada L4K 1B5

Astrophysicist/Astronomer

Applications are invited for a tenure-track appoint­ment to be made during the 1 9 8 3 /8 4 academic year as Assistant or Associate Professor. Ph D. or equivalent degree is required, and appointment w ill be at a level and salary commensurate w ith the appointee's accomplishments. Applicants from any sub-discipline w ith in the fie ld w ill be con­sidered. About one quarter of the Physics faculty (26 members, including three astronomers) are involved in research in astrophysics or earth and planetary atmospheres. Local facilities are available for observational astronomy: our 60 cm telescope has been instrum ented w ith modern s igna l­processing equipment, and faculty members may use m ajor Canadian observing fa c ilitie s . This position is advertised in accordance w ith a Cana­dian Immigration requirement which specifies that preference w ill be given to Canadian citizens and permanent residents. Send curricu lum vitae and names of three referees by June 30th, 1983, to:

Dr. W .J. M egaw , Chairm an. D epartm ent o f Physics,York U niversity,D ow nsv iew , O ntario ,Canada M 3 J 1P3

DEPARTMENT OF PHYSICSQUEEN'S UNIVERSITY

Replacement positions at the Assistant Professor level in astronomy and condensed matter physics are open for competition. The positions require a Ph D. and some teaching experience. Backgrounds in observational astro­nomy or low temperature physics are preferred. The duties w ill include teaching and research. The Department has vigorous research groups in applied and engineering physics, astronomy, condensed matter physics and nuclear physics.The positions, which are subject to the availability of funding, are available for a two year period from Sept. 1, 1983 and applications are invited until the positions are filled. Salary w ill be negotiable; the current Assistant Professor floor is $24,300. Opportunities may exist for continuation of the positions through research funding or for suitably qualified appointees through application for an NSERC University Research Fellowship.

Canadians and Landed Immigrants of Canada w ill be given preference in making this appointment and candidates of either sex are equally encouraged to apply.

A curriculum vitae and the names of three referees should be sent to:

Dr. M.J. Stott, Head,Department of Physics,Queen's University,Kingston, Ontario K7L 3N6

UNIVERSITY OF ALBERTA

DEPARTMENT OF PHYSICSGRADUATE ASSISTANTSHIPS

The Department of Physics invites applications for admission to programs leading to the degree of M.Sc. or Ph D. Excellent facilities exist for research in ASTRONOMY (observational and theoretical), ATOMIC PHYSICS, BIOMEDICAL and RADIO­LOGICAL PHYSICS, GEOPHYSICS, LOW TEMPER­ATURE and SOLID STATE PHYSICS, MASS SPECTROMETRY, NUCLEAR PHYSICS (low and medium energy), SPACE PHYSICS and THEORETI­CAL PHYSICS (statistical physics, particle physics, quantum field theory, general relativity, condensed matter physics and nuclear physics).

GRADUATE ASSISTANTSHIPS are available w ith stipends ranging up to $11,500 per annum (for 1983-84). Scholarship and Fellowship holders may be eligible for partial assistantships in addition to the ir award.

For fu rther inform ation, please w rite to:

Associate Chairm an,D epartm ent o f Physics,U n ivers ity o f A lberta ,E dm onton, Canada T6G 2J1 Phone (403) 4 3 2 -3 5 1 8

UNIVERSITY OF TORONTO

RESEARCH ASSOCIATEIN

INTERMEDIATE ENERGY PHYSICS

A Research Associate position is expected to be available for research in experimental intermediate energy physics. Candidates should have some back­ground and /o r interest in reactions induced by protons from the 200-500 MeV TRIUMF cyclotron.

Salary w ill be commensurate w ith experience at a m inim um of $21,000.00 per year. The term of the appointment is one year, norm ally renewable, starting summer 1983.

Applications w ith curricu lum vitae, and names of (3) referees should be sent to:

Professor R.E. Azuma D epartm ent o f Physics 60 St. George St.Toronto, O ntario, Canada M 5S 1A7

In accordance w ith Canadian Immigration regulations, this advertisement is addressed to Canadian citizens and permanent residents.

McMASTER UNIVERSITY

POST DOCTORAL FELLOWSHIPS TEACHING FELLOWSHIPS

RESEARCH ASSOCIATESHIPSA N D

GRADUATE ASSISTANTSHIPS

Applications are invited for post doctoral fellowships, teaching fellowships, research associateships and graduate assistantships in the Physics Department. Areas of research include theoretical physics, solid state physics, nuclear physics, quantum optics, mass spectrometry, chemical physics and astrophysics. E xperim ental research at M cM aste r fea tu res a tandem accelerator, a swim m ingpool reactor and the Institute for M aterials Research.

Applications for post doctoral fellowships, teaching fe llow sh ip s and research associa teships should include curricu lum vitae and the names of three referees.

Applicants for graduate assistantships should w rite for fu rther inform ation.

Write: C. Stager,Chairman, Department of Physics McM aster University Hamilton, Ontario LBS 4M1

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