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The Bulletin ofThe Canadian Associationof PhysicistsVol. 33 No. 3 Congress Issue 1977 Bulletin del’Association canadienne des physiciens Vol. 33 no. 3 Numéro du Congrès 1977

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Notice to CAP MembersBring this free copy of the Congress Issue to the annual congress in Saskatoon: other copies will be available at $3.00 each.

Avis aux membres de l ’ACPVeuillez apporter cet exemplaire gratuit du programme au Congrès à Saskatoon. Des exemplaires supplémentaires se vendront à $3.00 chacun.

NEW FROMTRACORNORTHERNLSI-11* MICROCOMPUTER BASED, MODULAR MCA

SIGNAL INPUT MODULES AVAILABLE:■ Choice of three ADCs; 50, 100 or 200 MHz

■ Multiple input scalers (MCS)

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■ Detector high voltage supplies, 2KV or 5KV available

■ Multiplex/routers for multiple PHA inputs

THE INNOVATIVE NEW TN-1 710 INCLUDESTHESE STANDARD FEATURES:■ Large 6.5" CRT display

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■ LSI-11 microcomputer

■ Field expandable with extra memory and new function modules

■ Additive and subtractive transfer

■ X - Y analog outpui tc plotters or recorders

■ New modular chassis capable of housing a wide variety of ADC, scaling and averaging inputs plus many data processing and display options

*LSI-11 is a registered trademark of the Digital Equipment Corp.

DATA PROCESSING MODULES AVAILABLE:■ Energy and time calibration for PHA/MCS data

■ Data processing including smoothing, stripping, normalization, plus spectrum integration and differentiation

■ Automatic learn and operate of complex analysis sequences

■ Peak or region of interest ratio

Many other input and processing modulesare planned to adapt the powerful TN-1710 tomeet your specific application.

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The Bulletin ofThe Canadian Associationof Physicists

Vol. 33 No. 3 Congress Issue 1977

/ ] / 7 c s v / } a )Physics in Canada

Bulletin del'Association canadienne des physiciens

Vol. 33 no. 3Numéro du Congrès 1977

La Physique au Canada

EDITORIAL BOARD/COMITÉ DE RÉDACTIONR. L. Clarke Editor/Rédacteuren chef

Associate Lditors/Rédacteurs AssociésMona L. Jento (managing/administration)Gilles Lamarche (textes français)

1977 CAP Congress, General Information

Congrès 1977, renseignements généraux

Maps/Plan du Campus

CAP Medallists 1977/Lauréats de l'ACP 1977

CAP Prize Exam 1977/Examen de l'ACP 1977

Future Congresses/Congrès futurs

E. R. FortinAdvertising Fditor/Rédacteur à la Publicité

J. E. HardyBook Review Editor/Rédacteur à la Critique des Livres

E. VogtEditorial Address :English Copy:R. L. Clarke Physics Department Carleton University Ottawa. Ontario KIS 5B6

Adresse de la Rédaction :Textes français :

Gilles Lamarche Département de Physique

Université d'Ottawa Ottawa, Ontario K IN 6N5

Invited Speakers/Conférenciers invités

Program Summary/Résumé du programme

Congress Program/Programme du Congrès

Author Index/lndex des auteurs

SUBSCRIPTION RATE/ABONNEMENT PAR AN $10.00 ADVERTISING. SUBSCRIPTIONS AN D CHANGE OE

A DDR ESS/PU B LICITE, ABONNEMENT ET CHANGEMENT D'ADRESSE:

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Canadian Association of Physicists Association Canadienne des Physiciens

Suite 903, 151 Slater Street Ottawa, Ontario K IP 5H3

Phone: (613) 237-3392

C anadian Association o f Physicists//'Association canadienne des physiciens / 977 A II rights reserved

OFFICERS OF THE ASSOCIATION/BUREAU PE DIRECTION COUNCIL/CONSEIL: 1976-77

*President R.J.A. Lévesque Université de Montréal*Past President A.E. Douglas National Research Council, Ottawa*Vice-President H,E, Johns Ontario Cancer Institute, Toronto*Vice-President Elect R.R. Haering Univeristy of British Columbia*Honorary Secretary-Treasurer J.S. Fraser A.E.C.L., Chalk RiverDirector - Members H. Lysons National Research Council, OttawaDirector - Affiliates J.K. Walker Energy Mines & Resources, OttawaDirector - Students L. Krauss Carleton UniversityDirector - Corporate Members S.H. Ungar Radionics Limited, MontréalEditor R.L. Clarke Carleton University

DIVISION CHAIRMEN

Aeronomy and Space Physics r:.G. Shepherd York UniversityATOMIC & Molecular Physics D. Carette Université LavalCanadian Geophysical Union I. Gough University of AlbertaCondensed Matter Physics R. Datars McMaster UniversityMedical & Biological Physics C,F. MacDonald Victoria Hospital, LondonNuclear Physics K. Mark McGill UniversityOptical Physics I. Stegeman University of TorontoParticle Physics Takahashi University of AlbertaPhysics Education D.C. Baird Royal Military College, KingstonPlasma Physics H.M. Skarsgard University of SaskatchewanTheoretical Physics H. Umezawa University of Alberta

COUNCILLORS/CONSEI LL ERS

British Columbia and Yukon D.F. Measday (1) University of British ColumbiaD.E. Lobb (2) University of Victoria

Alberta E.H. Pinnington (1) University of AlbertaH.R. Krouse (2) University of Calgary

Saskatchewan and Manitoba K.V. Paulson (1) University of SaskatchewanJ.S.C. McKee (2) University of Manitoba

Ontario - Southwest F.P. Koffyberg (1) Brock University, St. CatharinesM. Fujimoto (2) University of Guelph

Ontario - Central and North L.D. Reed (1) D.C.I.E.M., DownsviewG.A. Rubin (2) Laurentian University

Ontario - East D.C. Baird (1) Royal Military College, KingstonM.K. Sundaresan (2) Carleton University

Quebec C. St-Pierre (1) Université LavalBenoit Jean (2) INRS, Université du Québec

New Brunswick & Newfoundland H. Kiefte (1) Memorial University of NewfoundlandR.M. Lees (2) University of New Brunswick

Nova Scotia and Prince Edward Island E.W. Grundke (1) St. Francis Xavier UniversityA.M. Simpson (2) Dalhousie University

At large R. Carbonneau (1) C.R.D. ValcartierJ.H. Ormrod (2) Chalk River Nuclear Laboratories

EDITOR - CANADIAN JOURNAL OF PHYSICS P.R. Wallace McGill University

EXECUTIVE SECRETARY/SECRETAIRE EXECUTIF M.L. Jento

*Member of Executive Committee (Revised By-Laws 1973, Art. V, Sec. 2)(1) Term ends June 1977; (2) Term ends June 1978

CORPORATE MEMBERS ■- 1977MEMBRES CORPORATIFS - 1977

NICOLET CANADA LIMITED

ALLAN CRAWFORD ASSOCIATES LIMITED ONTARIO HYDRO

APTEC ENGINEERING LIMITED PHILIPS ELECTRONICS INCORPORATED

BARRINGER RESEARCH LIMITED POLYSAR LIMITED

BELL-NORTHERN RESEARCH LIMITED R.C.A. LIMITED

CTF SYSTEMS INCORPORATED RADIONICS LIMITED

CANADIAN GENERAL ELECTRIC COMPANY LIMITED UNIROYAL LIMITED

COMPUTING DEVICES COMPANY VARIAN ASSOCIATES OF CANADA LIMITED

EALING SCIENTIFIC LIMITED

EDWARDS HIGH VACUUM (CANADA) LIMITED McGILL UNIVERSITY

ELECTROVERT LIMITED MEMORIAL UNIVERSITY OF NEWFOUNDLAND

GULF OIL CANADA LIMITED UNIVERSITY OF OTTAWA

INSTITUT DE RECHERCHES DE L 1 HYDRO-QUEBEC UNIVERSITY OF SASKATCHEWAN

LUMONICS RESEARCH LIMITED UNIVERSITY OF VICTORIA

MacDONALD DETTWILER AND ASSOCIATES LIMITED UNIVERSITY OF WATERLOO

RENSEIGNEMENTS GENERAUX GENERAL INFORMATION

Le trente-deuxième congrès annuel de l'Association Canadienne des Physiciens aura lieu de lundi 20 juin au jeudi 23 juin 1977, à la cité universitaire de l'université de la Saskatchewan, Saskatoon, Saskatchewan. Le département de Physique est heureux d'annoncer le retour de ce congrès après un lapse de dix-huit années, et accueille chaleureusement les membres de cette profession.

GUIDE POUR L'ARRIVEE

Par avion: la cité universitaire est située à environ 10 milles au sud-est de l'aéroport.Nous recommandons le taxi aux personnes qui ont des réservations aux résidences universitaires. Le tarif est d'environ $5. et peut être partagé. Une limousine fait le trajet entre l'aérogare et certains hôtels (Park Town, King George, Holiday Inn). Le tarif est de $1.50 par personne.

Ceux qui ont des réservations aux résidences universitaires sont priés de se rendre au Saskatchewan Hall où se trouve le bureau des résidences, sauf le dimanche alors qu'il sera situé au Athabasca Hall, Gold Room, à partir de 13h. (Voir plan ci-joint).

Les personnes qui voyagent en voiture sont priées de noter que la cité universitaire est située tout juste au nord de la route 5 également appelée College Street sur la carte fournie dans cet exemplaire.

En cas de difficulté, on pourra rejoindre le comité local au numéro (306) 343-4271.

TRANSPORT LOCAL

Cité universitaire au centre-ville

1. L'autobus urbain no 2 "Pleasant Hill" mène au centre-ville et ensuite au Holiday Inn. Les départs s'effectuent à toutes les demi-heures de 6h le matin à minuit.

2. L'autobus no 7 "Hudson Bay Park" mène également au centre-ville en passant parl'hôtel Park Town de 6h à 19h. A partir de 19h, l'autobus no 9 "Idylwyld South" vous conduira de l'université au centre-ville avec arrêt tout près de l'hôtel Park Town.

Centre-ville à la cité universitaireL'autobus no 2 "University" en face du Holiday Inn vous conduira du centre-ville à la cité universitaire. Ceux qui demeurent au Park Town auront avantage à prendre l'autobus no 7 "Sutherland" à l'angle de la 25ième rue et Spadina, entre 6h le matin jusqu'à 19h, et l'autobus no 9 après 19h.

INSCRIPTION

Le bureau d'inscription pour le congrès sera situé au Athabasca Hall, Gold Room, le dimanche 19 juin, et au foyer de l'édifice de la physique les autres jours. Les participants pourront se

The thirty-second annual congress of the Canadian Association of Physicists will be held in Saskatoon, Saskatchewan, on the campus of the University of Saskatchewan from Monday, June 20 to Thursday, June 23, 1977. The Physics Department is pleased to see the return of the congress after a lapse of eighteen years and extends a warm welcome to members of the physics community.

ARRIVAL ORIENTATION

By Air:- The university campus is about 10 miles southeast of the airport. Taxi service is recommended for persons who have reservations at the university residences. The fare is approximately $5.00 and may be shared. A limousine service operates between the airport and the hotels in the downtown area (Park Town, King George, Holiday Inn). The fare is $1.50 per person.

Those with reservations at the university residence should proceed to Saskatchewan Hall where registration for accommodation will be at the main desk except on Sunday when it will be in the Gold Room of Athabasca Hall from 1:00 p.m. onward. (See map.)

Persons travelling to Saskatoon by car should note that the university campus is located just north of Highway 5, also labeled College Street on the map provided in this issue.

In case of difficulties the Local Committee may be contacted at (306) 343-4271.

LOCAL TRANSPORTATION

University Campus to City Centre1. Saskatoon Transit bus No. 2 "Pleasant Hill" goes to the centre of the city and then to Holiday Inn. The bus runs every half hour from 6:00 a.m. to midnight.2. Bus No. 7 "Hudson Bay Park" also goes to the city centre past the Park Town Hotel and provides this service only from 6:00 a.m. to 7:00 p.m. After 7:00 p.m. bus No. 9 "Idylwyld South" provides the transportation from the university to the downtown area with a stop near the Park Town.

City Centre to University CampusTo reach the university campus from downtown one may board bus No. 2 "University" outside the Holiday Inn. Those staying at the Park Town Hotel will find it convenient to take bus No. 7 "Sutherland" at Spadina and 25th Street between the hours of 6:00 a.m. to 7:00 p.m. After 7:00 p.m. the service is provided by bus No. 9.

REGISTRATION

Registration for those attending the congress will be in the Gold Room, Athabasca Hall, on Sunday, June 19, and in the foyer of the Physics Building on other days. Tickets for the

procurer leurs billets pour le banquet et autres activités au bureau d'inscription.

Le bureau d'inscription pour les résidences universitaires sera situé au Saskatchewan Hall, sauf le dimanche alors qu'il sera situé au Athabasca Hall, Gold Room.

Bureau d'inscription pour le congrès

Dimanche 19 juin: 14h à 21h, Athabasca Hall, Gold Room

Lundi à jeudi, 20 au 23 juin: 8h30 à 17h, foyer, édifice de la physique

Frais d'inscriptionMembre de l'ACP..................... $25.00Non-membres..........................$30. 00Enseignants d'école secondaire et étudiants prégradués............. $ 3.00

Les personnes qui accompagnent les délégués sont également priées de s'inscrire; dans ce cas il n'y a aucun frais d'inscription. Les billets pour le banquet et pour les diverses activités mondaines seront en vente au bureau de l'hospitalité près du bureau d'inscription.

LES REPAS

Pendant tout le congrès les repas seront servis à la cafétéria de Marquis Hall. Les personnes demeurant aux résidences universitaires ont deux options:

Option A — Chambre simple et 3 repas:$20.60 par personne par jour.Chambre double et 3 repas:$19.00 par personne par jour.

Option B — Chambre simple, petit déjeuner et déjeuner: $18.10 par personne par jour.Chambre double, petit déjeuner et déjeuner: $16.50 par personne par jour.

Ceux qui choisissent l'option B peuvent se procurer un billet pour le repas du soir à $4.00 le billet. Il faut acheter le billet au plus tard à 13h00 le jour même du repas.

Les personnes ayant choisi l'option A recevront un rabais de $4.50 s'ils assistent au banquet, mercredi le 22 juin 1977.

Les repas seront servis aux heures suivantes:

petit déjeuner 7h30déjeuner 12h00diner 17h00

Les personnes intéressées à l'excursion #2 (SED System Ltd. Tour) sont priées de noter que les autobus ne seront pas de retour à la cité universitaire â temps pour le repas du soir.

social program and the banquet will be available from the congress registration desk.

Registration for accommodation in the University Residences will be in Saskatchewan Hall on each day except Sunday when it will be in the Gold Room of Athabasca Hall.

Congress Registration Desk

Sunday, June 19: 2:00 p.m. to 9:00 p.m.,Gold Room, Athabasca Hall

Monday-Thursday, June 20-23: 8:30 a.m. to5:00 p.m., Physics Bldg. Foyer.

The schedule of registration fee is as follows:Members of the C.A.P................ $25.00Non members......................... $30.00High school teachers and undergraduate students............................ $ 3.00

Guests accompanying congress registrants arerequested to register, without fee. Tickets for the various social events and tours can be obtained at the hospitality desk located in the registration area.

ARRANGEMENT FOR MEALS

Meals will be served throughout the congress in Marquis Hall. Persons using residence accommodations have two options:

Option A — Single Room and 3 Meals:$20.60 per person per day.Double Room and 3 Meals:$19.00 per person per day.

Option B — Single Room with Breakfast and Lunch: $18.10 per person per day.Double Room with Breakfast and Lunch: $16.50 per person per day.

Delegates selecting Option B may buy an evening meal ticket on a daily basis at a cost of $4.00. The tickets must be bought prior to 1 p.m. on the day requested.

For persons selecting option A and attending the banquet, there will be a reduction of $4.50 for Wednesday, June 22, 1977.

The meal times are as follows:

8h45 Breakfast13h30 Lunch18h30 Dinner

Persons taking the SED System Ltd. Tour (outing #2) should note that the buses will not arrive back on campus in time for the evening meal.

STATIONNEMENT CAR PARKING

Les personnes demeurant à l'extérieur de la cité universitaire pourront se procurer au coût de $3.00 un permis pour stationner dans l'espace V pendant toute la durée du congrès, ou stationner dans les espaces B ou G à $1.00 par jour. Ces permis de stationnement pour le congrès seront en vente aux bureaux d'inscription. Les personnes demeurant aux résidences pourront se procurer les permis nécessaires lors de l'inscription au bureau des résidences.

Persons staying off campus will be required to obtain a convention parking sticker for lot V at a cost of $3.00 for the duration of the congress or they may park in lots B or G at a cost of $1.00 per day. Convention parking permits will be available at the registration desks. Persons staying in residence and requiring parking facilities will be provided with the necessary permits at the time of registration for accommodation.

COMITE LOCAL

Président Inscription Hospitalité BanquetProgramme local Visite des laboratoires PublicitéSalles de conférences Exposition Trésorier Hébergement Liaison K.V.

MontalbettiLlewellyn and K.V. Paulson Kennedy ShinManson and J. Maybank Gregory GuptaPaulson and E. Ansaldo KoehlerLlewellyn and R. Montalbetti Sof ko Paulson

LOCAL COMMITTEE

ChairmanRegistrationHospitalityBanquetSocial Program Laboratory Tours PublicityLecture Halls and A.V.ExhibitsTreasurerAccommodationLiaison /j

R.E.J.J.E.Y.M.A.H.J. B.I. C.

K. V.J . A . E.J. G.J.

Pour tous renseignements pendant le congrès, prière de vous adresser au comité local, bureaux du département de Physique, pièces 162 ou 157, téléphone: (306) 343-4271. Le service de placement de l'A.C.P. et le bureau de la presse seront à la pièce 132, et le bureau de l'executif de l'A.C.P. à la pièce 129, toutes dans l'édifice de la physique.

The Local Committee may be contacted at the Physics Department Offices, Physics 162, or 157, phone (306) 343-4271. ^ ^ ^ ? q / f Z £

The C.A.P. Placement Service and the Press Room will be located in Room 132, and the C.A.P.Executive Office in Room 129, all in the Physics Building.

EXPOSITION PAR LES MANUFACTURIERS ET LES EDITEURS

Il y aura un centre d'exposition industrielle semblable à celui des congrès antérieurs. Ce centre sera situé à l'étage principal de l'édifice de la physique et les sessions auront lieu dans les pièces adjacentes. Bien que plusieurs compagnies aient manifesté le désir d'exposer, aucun engagement n'a été conclu à l'heure actuelle. On s'attend toutefois à avoir les exposants habituels ainsi que quelques firmes canadiennes de l'ouest qui d'habitude n'exposent pas.

MANUFACTURERS AND PUBLISHERS EXHIBITION

There will be an industrial exhibit area similar to those at previous C.A.P. congresses. The exhibit area is on the main floor of the Physics Building in a central location; the sessions are being held in adjacent rooms. Although many companies have indicated an interest in exhibiting, no definite commitments had been made at press time in late March. Participants can anticipate seeing the regular exhibitors as well as a few western Canadian firms who have not normally participated in the past.

The list of Exhibitors will be included in the registration kit.

CAFE ET RAFRAICHISSEMENTS

Le café sera servi pendant les pauses de l'avant-midi et de l'après-midi.

REFRESHMENTS

Coffee will be available mid-morning and mid-afternoon.

IV

ACTIVITES MONDAINES ET EXCURSIONS

Les excursions suivantes qui ont été organisées ont été choisies en raison de leur intérêt particulier ou de leur inaccessibilité relative par mode de transport public. Les billets seront en vente à l'inscription aux heures mentionnées.

Excursion #1 - WESTERN DEVELOPMENT MUSEUM: lundi 20 juin

Ce musée possède une collection remarquable d'équipements agricoles et domestiques utilisés par les pionniers des prairies. L'attraction principale demeure la rue d'une ville prospère de 1910 qui a été reconstruite pour illustrer le style de vie de cette époque. Nombre limite:100 personnes.

Départ à 13h du département de Physique avec bref arrêt à l'hôtel Park Town et Holiday Inn dans cet ordre. Retour vers 16h. Billets y compris transport et rafraîchissements:

Adultes: $2.50 Enfants: $1.00

Prière d'acheter vos billets au bureau d'inscrip­tion de préférence le dimanche 19 juin, avant 9h ou, au plus tard, avant lOh le lundi 20 juin.

Excursion #2 - SED SYSTEMS LTD.: lundi 20 juin

SED systems Ltd. est une corporation universitaire qui, à l'origine, développait des charges utiles pour fusées et satellites. Cette corporation travaille encore dans le domaine des sciences spatiales avec des aéronomes canadiens soit à the Institute of Space and Atmospheric Studies (Université de la Saskatchewan) ou ailleurs. Les activités de cette corporation sont maintenant beaucoup plus variées, telles que systèmes de communication, dispositifs de télédétection et systèmes de micro-ordinateurs. Cette visite aura lieu de 16h30 à 18h30 au cours de laquelle des rafraîchissements seront servis. Nombre limite: 150 personnes.

On peut se procurer des billets soit le dimanche 19 juin ou le lundi 20 juin avant 12h au bureau d'inscription. Des billets pour le transport seront également vendus aux mêmes heures: $1.00 par personne. Les autobus quitteront l'édifice de la physique à 16h.

Excursion #3 - POTASH MINES: jeudi 21 juin

Deux visites ont été organisées pour deux groupes de 39 personnes soit à la Mine Cominco à Vanscoy ou à la Mine PCS Cory. Les visiteurs passeront leur temps dans les mines souterraines et à l'usine de broyage. Les autobus quitteront le département de Physique à 13h avec bref arrêt à l'hôtel Park Town et Holiday Inn, et reviendront à 16h30.

Adultes: $3.50 Enfants: $1.00

Les billets pour le transport seront vendus au bureau d'inscription le dimanche 19 juin ou avant 12h le lundi 20 juin.

SOCIAL EVENTS AND TOURS

Special tours have been arranged for the following major attractions which have been chosen both for anticipated interest or their relative inaccessibility by public transport. Tickets must be obtained in the registration area before the times specified.

Outing #1 — WESTERN DEVELOPMENT MUSEUM:Monday, June 20th

This museum has an outstanding collection of agricultural and domestic equipment used by the Prairie pioneers. The main attraction is a street of 'Boom Town 1910', which portrays the life style of that time. The tour is available for 100 persons.

Buses leave the University Physics Department at 1:00 p.m., calling at the Park Town and Holiday Inn in order, and returning by 4:00 p.m. Transportation, admission and refreshments:

Adults - $2.50 Children - $1.00

Tickets should be obtained in the registration area preferably on Sunday, June 19th, before 9:00 p.m., or, at the latest before 10:00 a.m. on Monday, June 20th.

Outing #2 -- SED SYSTEMS LTD.: Monday, June 20th

SED Systems Ltd. is a University Corporation, which was originally engaged in the development of rocket and satellite payloads: indeed the corporation is still involved in space sciences, and interacts with Canadian aeronomers both in the Institute of Space and Atmospheric Studies (University of Saskatchewan) and else-where. However, the corporation is now engaged in a much wider variety of activities including communication systems, remote sensing devices and microprocessor computer systems. A tour of the facilities and refreshments will be provided from 4:30 - 6:30 p.m. for 150 persons.

Tickets for the tour must be picked up either on Sunday, June 19th, or on Monday, June 20th before 12:00 noon, in the registration area.Those requiring transportation must also purchase tickets at that time: the cost is $1.00 per person, and buses will leave the Physics Building at 4:00 p.m.

Outing #3 — POTASH MINES: Tuesday, June 21st

Tours will be available for two groups of 39 persons to either the Cominco Mine at Vanscoy or the PCS Cory Mine. Time will be spent in the underground mining areas and in the milling factory. Buses will leave the University Physics Department at 1:00 p.m., calling at the Park Town and the Holiday Inn, and returning at 4:30 p.m.

Adults - $3.50 Children - $1.00

Transportation tickets should be purchased in the registration area on Sunday, June 19th or before 12:00 noon on Monday, June 20th.

Excursion #4 - HUTTERITE COLONY, DUNDURN: mercredi 22 juin

Cette excursion qui a été organisée pour 100 personnes au maximum permettra aux visiteurs de découvrir un genre d'agriculture très différent et des plus efficaces. Les autobus quitteront le département de Physique à 13h avec bref arrêt à l'hôtel Park Town et Holiday Inn, et reviendront â 16h30.

Adultes: $3.00 Enfants: $1.00

Les délégués pourront se procurer les billets de transport au bureau d'inscription dès l'arrivée, le dimanche 19 juin, ou avant 12h le lundi 20 juin.

VISITE DES LABORATOIRES DE RECHERCHE

Des arrangements spéciaux ont été prévus pour visiter les laboratoires de recherche de la cité universitaire. Ceux-ci comprennent le Laboratoire régional des Prairies du Conseil national de recherches, les laboratoires du Saskatchewan Research Council, la clinique des recherches sur le cancer, le Linear Accelerator Laboratory, les laboratoires du département de Physique et the Institute of Space and Atmospheric Studies. Toute information concernant les arrangements sera affichée au bureau d'inscription.

Outing #4 — HUTTERITE COLONY, DUNDURN:Wednesday, June 22nd

An afternoon visit will be available for up to 100 people, to a Hutterite Colony: this features a highly efficient and diverse farming style. Buses will leave the University Physics Department at 1:00 p.m., calling at the Park Town and Holiday Inn, and returning at 4:30 p.m.

Adults - $3.00 Children - $1.00

Transportation tickets should be purchased in the registration area upon arrival, but if possible on Sunday, June 19th or before 12:00 noon on Monday, June 20th.

RESEARCH LABORATORIES OPEN HOUSE

Research laboratories and installations on campus will be open to visits by arrangement. These include the National Research Council's Prairie Regional Laboratory; the Saskatchewan Research Council's Laboratories; the Cancer Clinic; the Linear Accelerator Laboratory; and the laboratories of the Physics Department and Institute of Space and Atmospheric Studies. Details of arrangements will be posted in the registration area.

ACTIVITES SPORTIVES

Les délégués ainsi que les personnes qui les accompagnent pourront utiliser la piscine située dans Physical Education Building pendant les heures réservées au personnel comme suit:

RECREATIONAL FACILITIES

C.A.P. delegates and companions will be allowed to use the swimming pool in the Physical Education Building during Faculty and Staff swimming periods according to the following schedule :

Dimanche 13h30 à 16h30Lundi à mercredi midi à 13h30Mercredi 20h30 à 22h30

SundayMonday to Wednesday Wednesday

D'autres sports tels que le tennis et squash sont également disponibles: premiers arrivés, premiers servis.

Other limited facilities like tennis and squash will also be available on first come first served basis.

RECEPTION ET BANQUET - mercredi 22 juin

L'université de la Saskatchewan recevra les congressistes et les personnes qui les accompagnent à une réception au Marquis Hall à 18h45. Le banquet aura lieu immédiatement après, à 19h30 au même endroit. $11.00 par personne, vin compris. Les billets doivent être achetés avant midi le mardi 21 juin car le nombre en est limité.

CAFE, FRIANDISES ET CONVERSATION - dimanche19 juin

Les membres du groupe local de la physique et leur épose recevront les visiteurs le dimanche 19 juin de 19h30 éa 21h30, édifice de la physique. Ce sera une excellente occasion de renouveler de vielles connaissances.

RECEPTION AND BANQUET -- Wednesday, June 22nd

The University of Saskatchewan is sponsoring a reception for congress participants and companions attending the banquet. The reception is scheduled for 6:45 p.m. in Marquis Hall. The banquet will follow at 7:30 p.m. at the same location. The cost is $11.00 per person (wine included). Tickets must be purchased before Tuesday noon as the number of tickets available is limited.

COFFEE, CAKE and CONVERSATION — Sunday, June 19th

The local physics group and wives will welcome visitors and renew old acquaintances on Sunday, June 19th from 7:30 to 9:30 p.m. in the Physics Building.

*

CANADIAN ASSOCIATION OF PHYSICISTS MEDALLISTS 1977

LAUREATS DE L'ASSOCIATION CANADIENNE DES PHYSICIENS 1977

CAP Medal for Achievement in Physics

A.H. Morrish

Herzberg Medal

M.B. Walker

CANADIAN ASSOCIATION OF PHYSICISTS PRIZE EXAM 1977

RESULTATS DE L'EXAMEN DE L'ASSOCIATION CANADIENNE DES PHYSICIENS 1977

One hundred and eighteen students from twenty nine universities competed this year. The exam was administered by R.G. Summers-Gill of McMaster University, Hamilton. An alphabetical list of the first eleven contestants with the names of the first prize-winner and the two students tied for second prize is given below:

Pierre Asselin Marcel Berard Richard Dale Jan Grygier Aksel Hallin Robert Holdom Robin Lindsey J.H. Morgan Robert Pike John Todoeschuck Lome Whitehead

Université de Montréal - FIRST PRIZEUniversity of Alberta - SECOND PRIZEQueen's UniversityUniversity of TorontoUniversity of British ColumbiaSimon Fraser University - SECOND PRIZEQueen's UniversityUniversity of WaterlooUniversity of TorontoMcGill UniversityUniversity of British Columbia

FUTURE CONGRESSES

CONGRES FUTURS

1978 - University of Western Ontario, London, June 12-151979 - University of British Columbia, Vancouver, June 18-211980 - McMaster University, Hamilton, June 15-191981 - Dalhousie University, Halifax

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.

LISTENERS

1) 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.

SPEAKERS

1) 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.

A) 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, practise giving your talk BEFORE the meeting. Remember, you are the ambassador of your department and institution, and you will be judged by your audience.

CHAIRMEN

1) Get to the session room about half an 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.

A) Keep the question periods interesting, lively and productive. Read over the papers in your session beforehand. If 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) Under no circumstances 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.

INVITED SPEAKERS/CONFERENCIERS INVITES

ANSALDO, E.J., UnivZtSity O f Saskatchewan; DB3: Electric Quadrupole Interactions in Metals: Systematic TrendsARSENAULT, H*, UnivZtSitë. Lavai; AE2: Statistical Properties of Laser Speckle BEAUDET, G* , U nivetsitli de M onttëdl; AA2: Nuclear Astrophysics in the Big BangBERGERSEN, B, , UnivZtSity Of BfiAtish Columbia; EBI : Theoretical Concepts in the Study of Quasi One Dimensional MaterialsBIRNIE, H.H. , UnivZtSity 0 Saskatchewan; DI2: The Saskatchewan Core Curriculum in PhysicsBURNETT, N.H., National Research Council of Canada; CA4: Scattering and Harmonic Generation in High Intensity CO2 Laser

Heating ExperimentsCALAPRICE, F.P., PtinCZton UnivZtSity; DAI: Symmetries in Nuclear Beta DecayCARETTE, J.—D., U nivetSitz Laval; AB4: Atomes et molecules adsorbés sur le tungstèneCARTER, A.L., Catlzton UnivZtSity; BCl: Exotic Atoms - Recent DevelopmentsCHEEKE, D. , U nivetSitZ dz Shztbtooke; EB4: Phonons dans les systèmes de dimension réduiteCOEY, J.M.D., IBM Thomas J . Watson ReSZOtch CZYlttZ and CNRS, Gxznoblz; AC3: New Varieties of Magnetic Order in Amorphous Solids COLLINS, M.F. McMascet UnivZtSity; AC4: The Order - Disorder Phase Transition in AlloysCORKUM, P.B., National Rzszatch Council o f Canada; EE3: Synchronization of Short High Power Laser Pulses for Plasma

Interaction StudiesCOSTAIN, C.C., National ReSZOtch Council o f Canada; DF1: The Canadian Primary Standard of Time and FrequencyDOUGLAS, A.E., National ReSZOtch Council Canada; AB1: High Resolution Molecular Spectroscopy in the Vacuum Ultra-Violet RegionFAULKNER, The Honourable J. Hugh, M inistry o f S ta te (5ot Scizncz and Technology; BGlFORSTER, J.S., Chalk RivCA Nuclzat Labotatotizs; DA3: Time Evolution Studies of Heavy Ion Induced Fission Using Crystal

Blocking TechniquesFORSYTH, P.A., National Rzszatch Council of Canada and U nivetsity 0 f Wzstztn Ontatio; ba4: Origins of Radio Auroral Studies

in CanadaFOWLER, W.A. , C a lifo tn ia In s t itu te o f Technology; AA1: Experiment and Theory Relevant to Explosive Nucleosynthesis in SupernovaeFRASER, J.S., Chalk Rivet Nuclzat L abotaioties; CC2: The Spallation Breeder of Fissile MaterialGREGORY, B.C. , 1NRS - In Z tg iZ ; CA2: Evaluation of Magnetoelectric Traps for Hot Plasma ConfinementHARRIS-LOWE, R.F., Royal M ilitâty C o llege ; DB2: Dissipation in the Transport of the Superfluid Helium FilmHUNTEN, D.M., U n iv Z tS ity Of Atizona; BA1: Atmospheric Minor Constituents in the Viking EraJOHNS, M.W., MeMastzt UnivZtSity; Dll: The Universities’ Expectations of High School PhysicsJOHNSON, D.C., Communications Rzszatch C zntte; EE2: CW Raman and Brillouin Fibre Optic LasersJOHNSON, R.R., UnivZtSity o f B r it is h Columbia and TRIÜMF; DA4: Nuclear Structure Studies Using Pion ProbesJONES, A.V., National Rzszatch Council o f Canada; BA2: Canadian Contributions to Auroral SpectroscopyJOSHI, Y., S t. Ttancis Kavizt U nivetsity ; AB2: Atomic Spectroscopy of Charged IonsKAMAL, A.N., U nivetsity o f A lbztta ; BC4: Radiative Decays of MesonsKELLY, F.M., U nivetsity o f Manitoba; AB3: Hanley Effect Study of Life-times and Collision Effects in Alkaline Earths KHANNA, F.C., Chalk Rivet Nuclzat Labotatotizs ; DB1: Elementary Excitations in Normal Liquid 3He; EA2: Pionic Effects in

Low Energy Nuclear PhysicsKIM, J.S., S ta te U nivetsity Of, New Votk a t Albany; BA3: Magnetometers and Modern All-Sky Cameras in Auroral Studies LITHERLAND, A.E., U nivetsity o f Totonto; EAl: Electrofission of Light ElementsLITTLE, M.S., Butzau Of Radiolooical H ealth, R o ck v ille , Matyland; DC2: Standards and Regulations on Radiation Devices in the U.S.A MACDONALD, W.J., UnivZtSity Of A lbztta and TRItiMF; EA3: Proton - Nuclei Interactions at Intermediate Energy MEASDAY, D., UnivZtSity o f S t i l is h Columbia; GA3: New Developments in Intermediate Energy PhysicsMORAWITZ, H. , ISM Rzszatch LabotatOty, San Jo s e , C a lifo tn ia ; EB3: The Role of Librons in Quasi ID Organic Conductors NG, J.N«, UnivZtSity Of A lbztta ; BC3: Characteristics of Charged Lepton Spectra from Neutrino-produced Sequential Heavy Lepton OFFENBERGER, A.A., UnivZtSity 0j$ A lbztta ; CA3: Nonlinear Laser Plasma Interaction Experiments ORMROD, J.H., Chalk Rivet Nuclzat Labotatotizs; CC3: Chalk River Superconducting Heavy Ion CyclotronOTTENSMEYER, F.P., Ontatio Cancet In s t itu te and U nivetsity o f Totonto; GAI: Electron Microscopy - Imaging of Atoms, Molecules

and CellsPATERA, G«, UnivZtSitZ dz Monttzal; EC2: A Classification of Sub-groups of Conformal Group of Space Time and Its Application

to Physical ProblemsPEARSON, J.M., U nivetSitz de Monttzal; DA2: Hartree-Fock Approach to Exotic NucleiPERZ, J.M., UnivZtSity o f Totonto; AC2: Experimental Determination of Spin Properties of Conduction Electrons in the Alkali Metals PINTAR, M.M., UnivZtSity Of Watztloo; CBl: Nuclear Spin Polarization Torsional Spectroscopy in Solids POUTISSOU, J.-M., TRIUMF and U nivetSitz de MonttZal; BC2: Rare Decay Modes of Pion and MuonROBERTSON, E.W., Waltzt Muttay C o lleg ia te In s t itu te , Saskatoon; DI4: The Saskatchewan Core Curriculum: the High School

Teachers' Point of ViewSERVRANCKX, R., UnivZtSity o f Saskatchewan; CCI: The Electron Pulse Stretcher Ring EROS and Its Applications SHEPHERD, G«G., Votk UnivZtSity; GA2: Observing the Dayside Magnetospheric Cleft s h e p h e r d, j.j., Sccenee Council o f Canada; BG2SHUTER, W.L.H., UnivZtSity Of B tit ish Columbia; AA4: Isotope Ratio of C and 0 Determination by Radioastronomy Techniques STEVENS, J.R. , UnivZtSity o f Guelph; DI3: The Ontario Core Curri culum in PhysicsSTOICHEFF, B.P., U nivetsity o f Totonto; DB4: Brillouin Scattering in Rare Gas Crystals; EEl: Tuneable Coherent Radiation

in the Vacuum UltravioletSUTHERLAND, P., McMOStet UnivZtSity; AAI: Neutrino AstrophysicsSUZUKI, M., Univet&ity Of A lbetta ; ACl: A New Type of Phase Transition in Two-Dimensional Quantal and Classical Spin SystemsTEICHMANN, J., U nivetSitz de Monttzal; CAl: Dynamic Stabilization of MicroinstabilitiesVAN DRIEL, H., UnivZtSity Totonto; AE1: Ultrafast Optical Response of Semiconductor PlasmasWADATI, M., UnivZtSity of A lbztta and Kyoiku U n iv etsity , Tokyo; EC3: Theory of Soliton: Nonlinear Waves in Dispersive MediaWALKER, M., UnivZtSity o f A lbetta and Max Planck In s t i tu te , Munich; EC1: Present Status of Gravitational TheoryWEILER, L., UnivZtSity Of B t it is h Columbia; EB2: Preparation and Study of Organic MetalsWELSH, H.L., U nivetsity of Totonto; CEI: High Resolution Raman Spectroscopy of GasesWESTFALL, G.D., Lawtzncz Betkelzy LabotatOty; EA4: Nuclear Fireballs in Heavy Ion CollisionsZAREMBA, E., Queen*S U nivetsity ; BB1: Physical Adsorption of Atoms on Solid Surfaces

IX

PROGRAM SUMMARY

RESUME DU PROGRAMME

The l e t t e r code o f the session, the s t a r t i n g t ime, the loca t ion and the top ics o f each session are

given in o rder. A l l sessions w i l l be held in the Physics Bu i ld ing .

(The personal names are those o f in v i te d speakers).

SUNDAY1, JUNE: 19

19:: 30 107

MONDAY, JUNE: 20

AA 9::00 107AB 9::00 130

AC 9: 00 103

AD 9: 00 128

AE 9: 00 II

BA 13:: 30 107

BB 13: 30 103

BC 13:: 30 128

BD 13:: 30 130BE 13: 30 127

BF 13:: 30 126

BG 20 :00 107

TUESDAY, JUNE 21CA 9:: 00 130

CB 9 :00 103CC 9::00 202

CD 9:: 00 126

CE 9 : 00 128CF 9::00 107

CG 9::00 127

CAP COUNCIL

Nuclear Astrophys ics; FOWLER, BEAUDET, SUTHERLAND, SHUTERAtomic and Molecu la r Physics Symposium; DOUGLAS, JOSHI, KELLY, CARETTEMagnetic P rope r t ies o f So l id s ; SUZUKI, PERZ, COEY, COLLINS

Plasma Physics IOptica l Physics; VAN DRIEL, ARSENAULT

B a lfou r W. C u r r ie Symposium - In v i t e d ; HUNTEN, JONES, KIM, FORSYTHSurfaces and Optica l P rope r t ies ; ZAREMBAP a r t i c le Physics Symposium; CARTER, POUTISSOU, NG, KAMALProper t ies o f L ig h t NucleiPhase T rans i t io n s

Nuclear Ins trumentat ion and Techniques

Physics and Soc ie ty ; FAULKNER, SHEPHERD

Plasma Physics Symposium; TEICHMANN, GREGORY, OFFENBERGER, BURNETT Magnetic Resonance; PINTARAcce le ra to r Physics; SERVRANCKX, FRASER, ORMROD, BLACKMORE

BiophysicsMolecu la r Physics; WELSH

S truc tu re o f Heavy Nuclei Supe rconduct iv i ty and Pos it rons in Sol ids

DA

DBDCDD

DEDF

DGDH

13:30 130 Nuclear Physics I ; CALAPRICE, PEARSON, FORSTER, JOHNSON

13:30 103 Condensed Mat te r Symposium; KHANNA, HARRIS-LOWE, ANSALDO, STOICHEFF13:30 126 Health Physics; LITTLE

13:30 128 Plasma Physics I I13:30 202 Ba lfou r W. C u r r ie Symposium - Contr ibuted I

13:30 V?9 /7 i Atomic Physics; COSTAIN

13:30 127 E lec t ron ic and Magnetic P rope r t ies of Metals 13:00 W Í / / 5 ” D iv is io n o f Physics Education Workshop

16:4516:4516:4516:4516:4516:4516:4516:4516:4516:45

202 D iv is io n o f Aeronomy and Space Physics ^W 9 n f D i v i sion o f Atomic and Molecu la r Physics 103 D iv is io n o f Condensed Matte r Physics ^

126 D iv is io n o f Medical and B io log ica l Physics ^130 D iv is io n o f Nuclear Physics ^

127 D iv is io n o f Optica l Physics165 D iv is io n o f P a r t ic le Physicsm / / s 'D iv is ion o f Physics Education128 D iv is io n o f Plasma Physics107 D iv is io n of Theore t ica l Physics ^

DI 19:30 107

WEDNESDAY, JUNE

EA 9:00 107EB 9:00 103

EC 9:00 130ED 9:00 128

EE 9:00 V &EF 9:00 127

EG 9:00 202

FA 14:00 107

Symposium o f the D iv is ion o f Physics Education; JOHNS, BÍRNIE, STEPHENS, ROBERTSON

22Nuclear Physics I I ; LITHERLAND, KHANNA, MACDONALD, WESTFALL Low Dimensional Systems; BERGERSEN, WEILER, MORAWITZ, CHEEKE

Theore t ica l Physics; WALKER, WADATI, PATERA Plasma Physics I I I

(Lase rs ; STOICHEFF, JOHNSON, CORKUM

L iqu ids and S t a t i s t i c a l Physics

Ba lfou r W. C u r r ie Symposium - Contr ibuted I I

CAP Annual General Meeting

THURSDAY, JUNE 23GA 9:30 107 P lenary Session; OTTENSMEYER, SHEPHERD, MEASDAY

13:00 CAP Counci 1

Marquis Hall

SUNDAY, JUNE 19 , 1977 ROOM 107

19:30 CAP COUNCIL

Chairman: R .J.A . Lévesque

MONDAY, JUNE 20, 1977 NUCLEAR ASTROPHYSICS

ROOM 107 Chai rman: N. de Takacsy

9:00AA1 Experiment and Theory Relevant to Explosive Nucleosynthesis in Supernovae

w.A. FOWLER, CaliloAYiia InitÁXuXc ojJ Technology

9:45AA2 Nuclear Astrophysics in the Big Bang

G. BEAUDET, U n iv o u s it e d e Montieal

10:30AA3 Neutrino Astrophysics

P. SUTHERLAND, McMaitea UniveAiity

11:15AA4 Isotope Ratio of C and 0 Determination By Radioastronomy Techniques

w.L.H. SHUTER, UniueAAity ol B/vtti&h Columbia.

MONDAY, JUNE 20, 1977 ATOMIC AND MOLECULAR PHYSICS SYMPOSIUM

ROOM 130 Chai rman: H.L. Welsh

9:00AB1 High Resolution Molecular Spectroscopy in the Vacuum Ultraviolet Region

A.E. DOUGLAS, National ReAeoAch Council o$ Canada

9:45AB2 Atomic Spectroscopy of Charged Ions

YOGI JOSHI, ST. Fnancii XauieA Uniozn&ity

10:30AB3 Hanley Effect Study of Life-times and Collision Effects in Alkaline Earths

F.M. KELLY, UniveAAity o£ Manitoba

11:15AB4 Atomes et molecules adsorbés sur le tungstène

J.-D. CARETTE, UnioCAAitë Laoal

2

MONDAY, JUNE 20, 1977 MAGNETIC PROPERTIES OF SOLIDSROOM 103CHAIRMAN: A.V. Gold

9:00AC1 A New Type of Phase Transition in Two-Dimensional Quantal and Classical Spin Systems

M. SUZUKI*, UniveAA-Uy ofa k lb en X a

Here we report some interesting results of Monte Carlo simulations for the two-dimensional quantal and classical XY-models. Monte Carlo simulations on the quantal system have been made on the basis of classical representations of it proposed by the present author. Classical cases have been studied by using the method of Binder and Rauch. The numerical results for the quantal XY-model show that there occurs in such a system a new type of phase transition without long-range order but with a singularity on the susceptibility. There is the appearance of vortices, as predicted by Kosterlitz and Thouless. More details will be reported at the Meeting together with some theoretical interpretations on the above results and on the similarity to spin glasses. The author would like to thank Professor C. Kawabata, Dr. A. Kuroda and Mr. S. Miyashita for allowing him to report here their partly unpublished work, and also thank Frofessor D.D. Betts for giving him a nice chance to visit Canada.

*Permanent Address: Department of Physics, Faculty of Science, University of Tokyo, Bunkyo-ku, Tokyo, Japan.

9:45AC2 Experimental Determination of Spin Properties of Conduction Electrons in the Alkali Metals

J.M. p e r z, Uyiiv&ià-tty o j( T oron to

The conduction electron g-factors in the alkali metals differ appreciably from those of a tree electron gas mainly because of many-body interactions, and the determination of precise experimental values of g is im­portant to a critical appraisal of theoretical techniques for solving the many-body problem in these metals. In this presentation, several methods for measuring g are reviewed, and one in particular, the analysis of the amplitudes and phases of de Haas van Alphen oscillations, will be described in detail. The special techniques used to overcome problems arising from the martensitic transformation in sodium will then be treated. Finally, the results for all the alkalis (particularly those due to the Cambridge Croup — B. Knech D.L. Randles and D. Shoenberg) will be summarized, with reference to recent theoretical determination.

10:30AC3 New Varieties of Magnetic Order in Amorphous Solids

J.M.D. COEY, IBM ThomaA J . WatAon ReAeaAck Cen-teA, and CNRS, Grenoble, France

Some novel forms of magnetic order are found in amorphous insulators and metals, their common feature being random orientation of the moments according to some probability distribution Ρ(Ψ). The determination of these structures from magnetization and Mossbauer data on materials with one or two chemical sublattices will be described, and a uniform nomenclature suggested. Physical mechanisms responsible for the scattered spin directions are i/ a broad distribution of exchange interactions or ii/ strong, randomly directed single-ion anisotropy. Both may be conveniently studied in amorphous rare-earth transition-metal alloys. The spin waves or other magnetic excitations and the condition for the appearance of magnetism in these materials will be discussed, and comparison made with disordered crystalline alloys, particularly the "spin glasses".

*Permanent Address

11:15AC4 The Order-Disorder Phase Transition in Alloys

M.F. COLLINS, McMaAteA UnÂvQAAÎty

The order-disorder phase transition, in a rather direct

phase transition in alloys is conceptually one of the simplest which exhibits a Experiments on both the equilibrium and the non-equilibrium properties test the way.

criticaltheory

MONDAY, JUNE 20, 1977ROOM 128Chairman: B.C. Gregory

PLASMA PHYSICS I

9:00

AD1 Plasma Generation in Electrothermal Shock Tubes,* B. ARMSTRONG and B. AHLBORN, Unlv, of British Columbia.— Electrical shock tubes In which the energy of a capacitor bank is discharged through electrodes directly Into a test gas can produce two very distinc­tive modes of flow. At high fill gas densities the power flux delivered to the gas creates a subsonic abla­tion front, which drives a shock Into the test gas. At low fill gas densities and high power Input a superso­nic heating wave Is created which propagates at high velocities Into the test gas converting It into plasma of about 2 to 3 eV. Details of the flow can be predic­ted if the heating characteristic is known. This func­tion between the absorbed powerflux and the final temperature of the plasma was determined by time re­solved measurements of pressure, temperature and front velocity.

9:^5ADL A New Mechanism of Anomalous Resistivity.*

A. HIROSE, Unlv. of Saskatchewan. — In conventional theories of anomalous resistivity it is assumed that relative drift between electrons and ions generates either electron-ion two-stream or ion acoustic insta­bility. However, it has frequently been observed1 that the anomalous resistivity has only a weak cor­elation with the ion acoustic instability. Here, it is shown that electron plasma fluctuations, generated by, e.g., runaway electron beams, can strongly enhance the ion density fluctuations through a nonlinear scat­tering process. The growth rate of the ion density fluctuations is of the order of W/nT- where uip-j_ is the ion plasma frequency, and W is the fluctuation energy density of the electron plasma mode. The effective collision frequency for the electrons is of the order of ωρ6 W/nTe where u)pe is the electron plasma frequency.

*Research supported by the National Research Council of Canada.1S.Q. Mah, Ph.D. thesis, Univ. of Sask. (1972).

9:15AD2 Diverging Cylindrical Solitons Excited with a

Probe.* T. CHEN and L. SCHOTT, Univ. of Saskatche­wan.— It has been shown previously that solitary ion acoustic waves can be excited with an insulated cylindrical probe.1 Details of the method of excita­tion will be given and the experimentally observed spatial and temporal evolution of the waves will be compared with numerical solutions of the Korteweg-de- Vries equation.

lT . Chen and L. Schott, Phys. Lett. A 58, 459 (1976).

*Research supported by a grant of the National Research Council of Canada.

9:30AD3 Experimental Study of Dynamic Stabilization of

Dissipative Drift Modes by Oscillating Azimuthal Magne­tic Field. S. Q. Mah, C. Boucher, J. Teichmann and H.W.H. Van Andel, Univ. de Montreal - The experiment is performed on a cylindrical plasma confined by an exter­nal magnetic field. The stabilization field is produ­ced by an alternating current at 100 kHz in a single conductor placed parallel to the plasma column just out­side the vacuum vessel. In an earlier experiment on an R.F. plasma, we have shown that under certain experimen­tal conditions, anomalous plasma losses apparently due to the presence of drift instabilities were drastically reduced. The drift waves were eliminated, while the phase angle between electron and potential perturba­tions was seen to approach zero, as predicted by theory. Here a quantitative study is made of the stabilization field threshold of critical damping of drift waves under various experimental conditions. For these mea­surements the plasma source has been changed to a hot cathode source to facilitate experimental control. Pre­liminary results show that the measured critical fields agree well with theoretical calculations.

10:00AD5 Orbit Function in the Theory of Strong Plasma

Turbulence. G. P0C0BELLI, Úniv. of Saskatchewan.—The standing question in the theory of strong plasma turbulence of which law [t3/3 (Ref.l), t14 / 3 (Ref.2),

k-v)2 (Ref.3) ] is correct for the exponential decay of the orbit function, is solved by taking into account in a more comprehensive way than done so far the correlation of the electric field fluctuations. It is shown thato.f. - exp I ik*vt 2m, ;.<!%.<<>I

(k.k*)2 t 2

(uik, -k' ·ν)2sinfw-. -k' >v)t l-cos(^-*,-k' ■

* 1-2 ------- : — + 2 --------------_ ---_ (w£.-k''v)t (ω-t-.-k1 ·ν)2 t2

The present expression yie^ds^a t**/8 law at small |^,-k,*v|t and a t2/(ω+,~k'·v)2 law asymptotically for the exponential decay. "Significant implications result for the velocity dependence of the diffusion tensor.

T.H. Dupree, Phys. Fluids 9, 1773 (1966).2T.J. Birmingham and M. Bornatici, Phys. Fluids 15,31778 (1972).A.M. Sleeper, J. Weinstock and B. Bezzerides, Phys. Fluids 16, 1508 (1973).

10:15Instabilités paramétriques dans un plasma chaud

faiblement turbulent. F. BRUNEL et J. TEICHMANN, Univ. de Montréal - Il a été démontré· · dans le cas unidimen- sionel que le mode ionosonore est profondément modifié en présence d'une faible turbulence de Langmuir. Lors­qu'un champ extérieur monochromatique pénètre un plasma faiblement turbulent au voisinage de la fréquence plas­ma, le couplage paramétrique se produit entre ce champ, un ou deux modes de Langmuir et le nouveau mode de bas­se fréquence résultant de l'interaction de la turbulen­ce sur le mode ionosonore. Une théorie cinétique tri- dimensionelle est développée et l'approximation des pha­ses aléatoires utilisée pour la turbulence. Des résul­tats sont dérivés pour différents paramètres de la tur­bulence et du champ H.F. extérieur.

1V.N. Tsytovich, Sov. Phys. JETP, 30, 83 (1970).

h

AD? Mesures sur un arc à courant alternatif. 25 kV, 60 kA, brûlant dans l'air. MICHEL G. DROUET, PIERRE KIEFFER, direction Sciences de base, et MICHEL ROY, laboratoire_Grande jouissance, IREQ, Varennes, Québec, Canada JÓL 2P0 — L'arc électrique brûle dans l'air entre deux électrodes distantes de 1 mètre. Le courant dans l'arc est variable de 1 à 60 kA et l'arc dure 1 se­conde. L'allongement de l'arc en fonction du temps est déterminé à l'aide d'une caméra rapide. A haut courant, l'allongement atteint 20 mètres. Des mesures simulta­nées du courant, de la tension et de l'onde de pression produite par l'arc, ont été effectuées. Les relations entre les paramètres électriques de l'arc, la longueur de l'arc et l'onde de pression générée seront présen­tées.

1 0 : 3 0

10:145AD8 Confinement of a Fusion Plasma bv a Cold Gas

Blanket.* B. AHLBORN, Univ. of British Columbia.—The particle end losses from a linear magnetic fusion reactor can be suppressed by establishing an ablation front in a cold gas blankét. The power density W(Watts/cm2) to drive the thermal front may be drawn from inside (energy end losses) or outside (auxiliary heating). With W below 10^W/cm2 and a D-T blanket the particle outflow is retardet. With higher W values the flow is completely stopped and the fusion plasma is recompressed by a shock wave traveling inwards from the ends.

11:00AD9 Dynamics of a High β Plasma Column.*

J.N. MCMULLIN and C.E. CAPJACK, Univ. of Alberta—The evolution of a high β linear θ-pinch plasma is inves­tigated using a square profile model. A new analytic solution for the self-similar area wave is found for the case β=1, γ=2 and an exact integral of the motion of the reflected area wave is derived in the general case. The evolution of the plasma variables in the region between the reflected area waves is calculated numerically. Ex­cept for cases in which /l-B ^ a/b (plasma radius/sole- noid radius), the density in this region is a slowly varying function of position. The relative fusion power production and total energy yield is estimated, assuming constant temperature, for combinations of β and b/a relevant to two conceptual designs. It is found that in most cases significant power is produced after the area waves have reflected from the mid-plane of the sole­noid. The model predicts that programming the applied magnetic field to simulate infinite b/a enhances the yield by ^85% for a 3-m neutron source but only by ^18% for a 1-km fusion reactor.

*Supported by the National Research Council of Canada.

Measurement of Stark Broadened Profile of Hell 4686A.* Μ. E. BACON, A. J. BARNARD and F. L. CURZ0N, Univ. of British Columbia.— Stark broadened profiles of the Hell 4686A line were measured using a Z-pinch plasma as source. The electron density was de­termined from the halfwidth of the Hel 3889 line and the temperature from the intensity ratio of the Hell 4686 and the Hel 3889 lines. The electron densities covered the range 0.5 to 2,3xl017cm3 and the electron tempera­ture was 4 ev. The plasma homogeneity was checked by varying the length of the column observed. The experi­mental profiles are in better agreement with the recent calculations of Greene than with the earlier calcula­tions of Kepple.

♦Supported by the National Research Council.

1 1 : 1 5

11:30AD11 Electron Collisional Ionisation Rate Measure­

ments of Lithium-like Nitrogen and Oxygen.* E. KÂLLNE, Univ. of British Columbia, and L.A. JONES, Los Alamos Scientific Laboratory.— The hot, dense plasma created by a 60kJ, 60kV thetapinch has been used to measure ionisation rates of nitrogen and oxygen. The temporal and radial temperature and density distributions are measured with 90° Thomson scattering and holographic interferometry using a 2J, 20 ns ruby laser. Using a 2.2 m grazing incidence monochromator, the time evo­lutions of strong VUV lines from the different ion sta­ges are observed. The plasma light emission is predic­ted by solving the coupled rate equations with the ob­served temperature and density distributions included and by using a theoretical ionisation rate as input. These rates are adjusted until best fits with observed profiles are obtained. By including density corrections in the plasma model like depression of ionisation po­tential and 2s-2p mixing of the ground state as well as corrections for the temperature dependence of the ex­citation rate and for end losses in the plasma we found that the observed ionisation rates agreed to within 10% from Kunze's semi-empirical formula,♦Work performed under the auspices of US ERDA.

5

MONDAY, JUNE 20, 1977 OPTICAL PHYSICSROOM 129Chairman: J. Lit

9:00AE1 Ultrafast Optical Response of Semiconductor Plasmas

H. VAN DRIEL, Univ&UAXy 0 & ToKOYltO

9:45AE2 Statistical Properties of Laser Speckle

H. ARSENAULT, U n i v v u l t z L a v a l

10:30 Break

10:45AE3 Meas u re m e n t o f S u r f ace Roughness by U s in g Two-

Wa v e l e n g t h S p e c k le P a t t e r n s . H I TOSH I F U J I I and JOHN

W.Y. L I T , U n i v . L a va 1 . --A new method t o m easu re s u r f a c e

ro u g hn e ss i s s t u d i e d t h e o r e t i c a l l y b y m ak in g use o f t h e

s t a t i s t i c a l p r o p e r t i e s o f two m o n o c h ro m a t ic s p e c k l e p a t ­

t e r n s . An o p t i c a l l y rough s u r f a c e i s i l l u m i n a t e d by a

tw o - w a v e le n g th l a s e r beam, and t h e two s p e c k l e p a t t e r n s

due t o each o f t h e w a v e l e n g t h s a r e a n a l y s e d i n t h e f a r -

f i e l d . The rms d i f f e r e n c e be tw ee n t h e i n t e n s i t i e s o f

t h e two p a t t e r n s i s d e f i n e d and e v a l u a t e d as a f u n c t i o n

o f t h e rms o f t h e s u r f a c e r o u g h n e s s . I t i s shown t h a t

t h e rms d i f f e r e n c e i n c r e a s e s w i t h i n c r e a s e o f t h e s u r f a ­

ce r o u g h n e s s . F rom t h i s r e s u l t , a s im p l e method f o r

m e a s u r i n g s u r f a c e r o ug hn e ss i s d e v i s e d . The e f f e c t i v e

m e a s u r i n g r a n g e , o r t h e s e n s i t i v i t y , can be changed by

v a r y i n g t h e two w a v e l e n g t h s o f t h e l a s e r beam. When an

a r g o n io n l a s e r i s used f o r i l l u m i n a t i o n , a p p r o p r i a t e

w a v e l e n g t h s can be chosen t o g i v e f u l l s c a l e r a ng es o f

rms ro u g h n e s s v a r y i n g f r o m 0 - 0 . Sum t o 0-Aum, t h u s c o v e r ­

i n g t h e most i m p o r t a n t r e g i o n s o f p r a c t i c a l s u r f a c e

ro u g hn e ss o r d i n a r i l y e n c o u n t e r e d . Some c o m p u te r s im u ­

l a t i o n s t u d i e s a r e co nd u c te d and t h e y a r e i n good a g r e e ­

men t w i t h t h e t h e o r e t i c a l r e s u l t s .

11:00AE4 Nonlinear Optical Phenomena at Surfaces.* V. SO

and G.I. STEGEMAN, Univ. of Toronto— A general theory of nonlinear wave phenomena at surfaces has been developed and will be illustrated by treating harmonic generation in thin film optical waveguides which are of current interest in communications. A waveguide typically con­sists of a high refractive index film (thickness - one optical wavelength) deposited on a low refractive index substrate. The nonlinear polarization field is calcu­lated in both the film and substrate and the inhomoge­neous wave equation for the Hertz vector is solved. The polarization generated electric and magnetic fields are

derived in the usual way from the Hertz vector and dis­continuities in the tangential E and H and normal D and B fields are calculated at both surfaces. New normal modes (solutions to the homogeneous wave equation) are then introduced to satisfy the electromagnetic boundary conditions. One of these modes evolves with propagation distance into a guided wave second harmonic. The pre­dictions of this theory differ with those of "overlap- integral” methods which require averaging of the wave equation over the film thickness and neglect the bound­ary conditions.

*Research supported by NRC.

11:15Displacement of an Electromagnetic Beam upon

Dielectric Reflection." L.A.A. READ, Wilfrid Laurier Univ., G.E. REESOR, and MAN WONG, Univ. of Waterloo - The theoretical investigations of Antar and Boerner* concerning the sideways displacement of an electro­magnetic beam upon external reflection from a dielec­tric have been extended. We have adopted a similar plane wave expansion to predict values of the shift for 3 cm microwaves for both perpendicular and paral­lel polarization for reflection from a dielectric prism whose index of refraction is 1.685 and from a dielectric slab, 9.5 cm thick, whose index of refrac­tion is 1.63. Experimental results will be presented which show that for the single reflection case (prism) the direction of the shift is dependent on polariza­tion; that is, for parallel polarization the shift is backwards. For the multiple reflection case (slab), the results show the direction of the shift is forward for both polarizations.lAntar, Y.M. and Boerner, W.M., 1974, Can. J. Phys., 52, 962-'Work supported by N.R.C.

6

MONDAY, JUNE 20, 1977 BALFOUR W. CURRIE SYMPOSIUM

ROOM 107Chairman: N.C. Gerson

13:00BAl Atmospheric Minor Constituents in the Viking Era

D.M. HUNTEN, U niveJU -ity 0 j( k i lz o n a .

14:10BA2 Canadian Contributions to Auroral Spectroscopy

A. VALLANCE JONES, N a t io n a l VtAQJVich C o u n c il oj Canada

14:50 Break

15:10BA3 Magnetometers and Modern All-Sky Cameras in Auroral Studies

J,S. KIM, S t a l e L in iv en à ity Wew Vo/ik a t A lbany

15:50BA4 Origins of Radio Auroral Studies in Canada

P.A . FORSYTH, N a t io n a l RcA eaach C o u n c il ofi C anada an d t h e i t n lv e n t i t y o Wet t& in O ntan lo

MONDAY, JUNE 20, 1977 SURFACES AND OPTICAL PROPERTIESROOM 103

Chairman: R,R, Parsons

13:30BB1 Physical Adsorption of Atoms on Solid Surfaces

E. z a r e m b a, Q ueen'6 U n io o ju it y

A review of the adsorption of atoms on solid surfaces is presented. Particular emphasis is placed on a description of the adsorption of the rare gases on metals. In these systems the attractive atom-solid interaction is the van der Waals (or polarization) force and methods for its calculation are described.The repulsive interaction is associated with exchange effects due to the overlap of the atomic and metallic electronic wave functions. The full interaction has recently been calculated for the case of helium on simple and noble metals. Application of the theory to the other rare gas atoms is discussed. A survey of the experimental techniques used to probe the atom-surface interaction is also given.

14 : 15Low Temperature Photoconductivity in Amorphous

ZnSe*. R. SHIAH, P.K. LIM, D.E. BRODIE and P.C. EASTMAN University of Waterloo, The Photoconductivity Δσρ, in a-ZnSe, was studied from 400K to 50K. In addition to the normal high temperature results, where a maximum (near 390K) occurs in Δσρ, near the temperature at which the occupancy of the recombination levels changes from being dominated by photoexcited carriers, a minimum is observed in Δσρ near 150K as the temperature decreases. Δσρ is frequency dependent, (i.e. Δσρ 'v ω ; s ^ 0.6), suggesting that Δσρ may be due predominantly to carriers hopping in localized states.

A model is proposed to account for this new observation, involving a recombination centre near, but not at, the dark Fermi level. A possible mechanism for the recombination is suggested.

This work is supported by the National Research Council of Canada.

14:30BB3 Some Properties of Amorphous ZnSe.* P.K. LIM

and D.E. BRODIE, Unlv. of Waterloo— Amorphous ZnSe has been prepared by vacuum deposition onto glass and fused quartz substrates cooled to 'vlOO K. As made films are unstable and they must be annealed to obtain mature amorphous specimens. Rapid crystallization of a-ZnSe, occurs above 450 K and this is an activated process with an energy of 1.9 eV. The annealling may be ob­served in the d.c. conductivity when the sample is warmed for the first time from 100 to 410 K. The sub­sequent analysis of the d.c. conductivity, photo con­ductivity, thermoelectric power, and a.c. conductivity indicates that a-ZnSe can be described satisfactorily with a Mott type model. Electrically, only hopping in the band tail states and at the Fermi level can be ob­served at temperatures below 410 K. Below 270 K the conduction process is consistent with variable range hopping and the density of states N(Ef), at Ef is 3 x lOl? cm“3/eV if Vp^ 4 x 10iU sec”i as calculated from a deformation potential according to Millar and Abrahams (1960). Evidence is presented which indicates that annealling reduces N(Ef).

*This work is supported by the N.R.C. of Canada A. Millar & E. Abrahams, Phys. Rev. 120 (1960) 745

7

114:1* *5BBÍ4 La diffusion de__la lumière par les

couches métalliques qranulairesT* V. V.TRUONG, Univ. de Moncton; G. D. SCOTT, Univ. of Toronto.-** Dans les études sur les proprié­tés optiques des couches métalliques granu­laires, on a souvent négligé la diffusion de la lumière par les particules formant la couche. Les couches sont considérées comme des milieux continus possédant des propriétés optiques effectives. La contribution de la lumière diffusée dans certains cas peut cepen­dant devenir considérable. Dans la présente étude, la distribution spectrale de la lumière diffusée à partir des couches granulaires d'or, de cuivre et d'argent a été mesurée dans la région de 0.35 à 1.0 pm. Les couches minces sont préparées de telle façon à obtenir des particules de forme régulière et de grandeur considérable, allant jusqu'à 1000A. La dis­tribution angulaire de la lumière diffusée a été aussi mesurée. Les mesures expérimentales ont été ensuite comparées aux résultats calcu­lés à partir d'un modèle de sphéroïdes.*Subventionné par le C.N.R.C.

15:15BB5 Aueer Spectroscopic Evidence that Plasma Oxida­

tion Involves Mass Transfer from the Cathode to the Anode, J.D.LESLIE and V.KEITH, Physics Dept., Univ. of Waterloo - It has been generally assumed that the oxygen ions in the plasma are responsible for the oxidation of the anode. Reactive sputtering of cathode material has been viewed as a possible source of contamination of the plasma oxide layer that could be avoided by having the anode sample facing away from the cathode. We present clear evidence, through the use of Auger spectroscopy, that cathode material is transported to the anode during plasma oxidation, even when the anode is facing away from the cathode and is located on the back of a shield. In these experiments we have used anodes of Ta,Nb and Cu and cathodes of Ta,Nb,Al and C ,in various combinations. Our results indicate that cathode material does not deposit on the anode unless the anode is passing a current. The oxide on the anode formed by plasma oxidation is gener­ally formed of two layers, with the outer layer being composed of oxide of the cathode material and the inner layer being composed of oxide of the anode material. We will present evidence that the transfer of cathode mater­ial to the anode is an integral part of the plasma oxidation process.

15:30BB6 ATR Spectra of Alternating Plasma-

Dielectric Layers.* G. J. KOVÁCS and. G. D. SCOTT, Univ. of Toronto— The method of attenuated total reflection (ATR) can be used to optically excite electromagnetic waves guided by thin films. We report a study of the ATR angular spectra of alternating silver-dielectric films concentrating on the two systems Ag-diel.-Ag, and Ag-diel.-Ag-die1.- A g . The resonances of the three layer system are observed to split

into doublets in the five layer system. This splitting occurs for both parallel and perpen­dicular polarization of the incident radiation and is predicted by classical electromagnetic theory. Surface roughness of evaporated di­electric films has an important effect on both p- and s-polarized spectra. The roughness at a metal-dielectric interface is modelled as a thin cermet layer, which accounts for certain discrepencies between the experimental resonan· ces and those calculated by assuming perfectly planar metal-dielectric interfaces."Supported bj the National Research Council of Canada.

15:^5Shell Model of the Bound Multiexciton Complexes in

Si.* M.L.W. Thewalt, G. Kirczenow and R.R. Parsons, Univ. of British Columbia. The luminescence line se­ries recently observed in lightly doped Si at liquid He temperatures are explained in terms of a shell model description of the bound multiexciton complexes. Many of the predictions of the shell model are borne out by our new experimental results. The donor bound exciton is found to have bound excited state as postulated in the theory. Preliminary results of very high resolu­tion studies of these lines undertaken with a Fabry- Perot interferometer will also be described.

* Supported by the National Research Council of Canada.

l6:00Excitation Characteristics of the 0.93

μ Luminescence of C u ? 0 . D. J. KENWAY,C. DUVVURY and F. L. WEICHMAN, Univ. of Alberta.--Despite extensive study, the mechan­isms of the 0.93 μ luminescence of CU2O are not entirely understood. There is some evidence that exciton capture is responsible for the 0.93 μ luminescence stimulated by excitation with visible radiation. Through the use of a tunable dye laser we have been able to generate some further evidence of this by studying at a number of different excita­tion wavelengths the luminescent output as a function of temperature.

MONDAY, JUNE 20, 1977ROOM 128Chairman: H.C.S. Lam

PARTICLE PHYSICS SYMPOSIUM

13:30BC1 Exotic Atoms - Recent Developments

A . L. CARTER, C axÍZ ton UvUvQAàlty

14:13BC2 Rare Decay Modes of Pion and Muon

j.-M. POUT IS SOU, TRIUMF and U yU vfM itz d z M ow tA zal

Rare decay modes of pions and muons are very good tools to improve our understanding of the weak interaction. Tt is hoped that the advent of meson facilities will allow these difficult experiments to be significantly improved. At TRIUMF these experiments exploit the good performances of very large sodium Iodide detectors which will be discussed. We will present progress report on several experiment1 currently underway at TRIUMF; the study of the weak axial-vector form factor of pions via the π -*■ evey decay mode, the studv e-u universality via a high precision determination of the n->eve decay mode. Results will be presented on the recent experiment that looked for the u ■* ey decay mode.

^Collaboration Université de Montreal, University of British Columbia and University of Victoria.

13:00BC3 Characteristics of Charged Lepton Spectra from Neutrino-produced Sequential Heavy Lepton

J.N. NG, l lH iw u -c ty M b w t a

The production of a charged sequential heavy lepton, L+, in high energy v^N scattering via the Bethe-Heitler process and its subsequent leptonic decay into e*v triplet is calculated and the cross section for the production of 2 GeV/c2 heavy lepton at 50 GeV incoming energy is ^10 U3cm2 with usual four-Fermi coupling. One characteristic feature of the charged decay products is the large asymmetry favoring u“ due to threshold effects persisting at presently available energies.

15:45BC4 Radiative Decays of Mesons

A.N. KAMAL, UilivQAA'Lty O AZbçAÙL

MONDAY, JUNE 20, 1977 PROPERTIES OF LIGHT NUCLEIROOM 130Chairman: H.$. Caplan

13:30B D l P i o n i c X Rays f r o m He l i u m T h r e e - G.R . MASON,

G . A. BEER, S .K . K IM , A. O L IN , R.M. PEARCE, U n i v . o f

V i c t o r i a , and D . A . BRYMAN, M.S. D I X I T , J . A . MACDONALD,

J . S . V INCENT, TR IUMF — N e g a t i v e p io n s p roduced a t t h e

TR IUMF c y c l o t r o n w e re s to p p ed in a l i q u i d h e l i u m - t h r e e

t a r g e t 1 o p e r a t e d a t 2° K. X r a y s e m i t t e d d u r i n g th e

p io n a to m ic cascade w e re d e t e c t e d w i t h a S i ( L i ) d e t e c ­

t o r h a v in g a r e s o l u t i o n o f 160 eV a t 6 k eV . E x p e r i ­

m e n t a l l y - d e t e r m i n e d v a l u e s w i l l be p r e s e n t e d f o r t h e

s t r o n g i n t e r a c t i o n s h i f t and f o r t h e L o r e n t z î a n l i n e

w i d t h f o r t h e K t r a n s i t i o n s ; p r e l i m i n a r y r e s u l t s i n ­

d i c a t e ag re e m e n t w i t h t h e o p t i c a l model t r e a t m e n t by

K r e 11 and E r i c sőn 2 .

1 J . S . V i n c e n t and W.R. S m i t h , N u c l . I n s t r . and Me th .

U_6 (197A) 551.

2 M . K r e l l and T . E . 0 . E r i c s o n , N u c l . P h y s . B 11 ( 1969) 521 .

* S u p p o r te d by t h e N a t i o n a l R e s e a rc h C o u n c i l o f Canada.

13:L5BD2 P i o n i c 2 p - ls T r a n s i t i o n s i n 12Na and 2 t4Mq

R.M. PEARCE, G . A. BEER, Ο . MASON, A. OLIN . P. P0FFEN-

BERGER, U n i v . o f V i c t o r i a , and D . A . BRYMAN, M.S. D I X I T ,

J . A . MACDONALD, TRIUMF — N e g a t i v e p io n s f ro m a p ro d u c ­

t i o n t a r g e t e x t e r n a l t o t h e TRIUMF c y c l o t r o n w e re c o l ­

l e c t e d and focu sed by a m a g n e t ic c h a nn e l 8 m i n l e n g t h ,

d eg raded i n p o l y t h e n e , and s u b s e q u e n t l y s to pp ed i n sam­

p l e s o f L i F , Na m e ta l and Mg m e t a l . The X r a y s accom­

p an y in g t h e cascade o f t h e p io n s t h r o u g h th e a to m ic

o r b i t s w e re d e t e c t e d i n a h ig h r e s o l u t i o n i n t r i n s i c

ge rman ium d e t e c t o r . The Is l e v e l i s o f i n t e r e s t b e­

cause t h e o v e r l a p o f t h e p io n w i t h t h e n u c l e u s causes

a b ro a d e n in g due to n u c l e a r a b s o r p t i o n o f t h e p io n and

a s h i f t i n e n e r g y f ro m t h e no rma l e l e c t r o m a g n e t i c v a l u e

due to th e p io n - n u c le u s i n t e r a c t i o n . The e n e r g y o f t h e

2 p - 1 s X r a y i n p i o n i c f l u o r i n e ( f ro m a p r e l i m i n a r y a n ­

a l y s i s ) i s 19A.9 * 0 . 3 keV and th e w i d t h i s 9-60 i

O . 7 O keV . These v a l u e s d e v i a t e somewhat f ro m p r e v i o u s

w o r k 1 *2 and have e r r o r s a p p r o x i m a t e l y two t im e s s m a l l e r

R e s u l t s f o r Na and Mg X r a y s w i l l a l s o be p r e s e n t e d .

1 G.Backenstoss e t a l . , Phys.Lett. 2 5B, No.5 (1967) 3652 D .Κ . A n d e rs o n e t a l . Phys . Rev. 18jT, No. 1 ( 19 6 9 ) 9

9

BD3 The Four Body Reaction ‘ L i (p.pa)np as a Probe

o f the C lu s te r S t ru c tu re o f " L i r D . I . BONBRIGHT,

J.S .C. McKEE and J.W. WATSON, Cyc lo tron L abo ra to ry ,

Univ . o f Manitoba -- The re a c t io n s 6L i(p ,pa )d and 6L i(p ,pa )np have been s tud ied a t a bombarding energy

o f 39.8 MeV in a geometry s u i ta b le fo r observing quas i­f r e e sc a t te r in g . Evidence is presented fo r the e x i s t ­

ence o f a c lu s t e r s t ru c tu re o f alpha p a r t i c l e plus a neutron-proton p a i r w i t h in the ground s ta te o f 6L i .

★Supported by the NRC of Canada.

_LU : 00

It : 151 9 8BDh Additional Results on the Be(p,pn) BeReaction H. JEREMIE, G. KENNEDY" and L. LEMAl^ * S * Lab. de Physique Nucléaire, Univ. de Montreal,— New mea­surements have been performed on the yBe(p,pn)$Beg<s reaction. At 10 and 12.7 MeV the old measurements! with ôp — θη = 45° were repeated with longer flight path for the neutrons, and at 12.7 MeV the angular cor­relation between protons and neutrons has been measured keeping θρ fixed at 45v and varying θη. Furthermore, the calculation of quasifree scattering of protons on the loosely bound neutron has been repeated with full Coulomb wave-functions instead of asymptotic ones.The experimental results as well as the new calcula­tion continue to support the validity of the attenua­tion model of Rogers and Saylor^.

. Jérémie and G. Kennedy, Can,Journ.Phys. 55 (1977) 261.

2J.G. Rogers and D.P. Saylor, Phys.Rev. C6 (1972) 734.

Present address: Ecole Polytechnique, Montreal

14:30BD5 The 180(p,q)15N Reaction Cross-Section at Low

Energy. H.B. MAK, G.T. EWAN, H.C. EVANíTand D.J. MacARTHUR, Queen's Univ.— The cross-section for the re­action 180(p,a)]bN has been measured over the energy range 660 keV ^ E i 225 keV, using thin enriched AÍ2O 3 targets evaporated onto 5 pgm/cm2 carbon foils. Preliminary results indicate that the S-factor extra­polated from our data lies in the range 60 MeV-barns £ S(0) < 300 MeV-barns. This is at least a factor of three larger than the previously estimated value of S(0) ~ 18 MeV-barns deduced by assuming that the re­action at low energies is mainly contributed by thetails of the two known resonances at E_= 662 keVand 825 keV. Our results would suggest that resonances near the 180 + p threshold contribute significantly to the 180(p,ot)15N reaction rate.

15:00BD6 A J1T=3 Isospin M ixed Doublet in 18F,* W. E.

KIESER, K. P. JACKSON, I. BERKA, R. E, AZUMA, Univ. of Toronto ; A. B. MCDONALD, AECL, Chalk River Nuclear Lab­oratories ; H. B. MAK, W. MCLATCHIE, Queen1s Univ.— The resonance at Ex=6241 keV in 170(p,y)^F and (α,γ)10Finvestigated by Rolfs et a^1 has been found to be a closely separated doublet (ΔΕχ=2.19+.07 keV). Resonance strengths in 170(p,y)18F, *70(p,ot) ll4N and 1ι+Ν(α,γ)1θΡ have been measured and partial widths for these levels have been obtained. The doublet was further investigat­ed by means of the ^HeC1 ,a) ll+N reaction and the dif­ferentially pumped gas target at CRNL. Analysis of these data with R-Matrix theory yielded J7T = 3 for both levels and accurate values of the α-particle widths (raL=133±4 eV ; Γαυ=137+4 eV). The reduced a-widths and the El and Ml transition strengths indicate that the doublet arises from the nearly complete mixing of T=0 and T=1 eigenstates separated by <, 50 eV.

'c.· Rolfs et al, Nucl. Phys. A199, 306 (1973).

*Partially supported by grants from NRC Canada.

An Accurate DSAM Lifetime Measurement of the 3.35 MeV 4+ Level in ^Ne. T.K. ALEXANDER, G.cV BALL, W.G. DAVIES & J.S. FORSTER, AECL. Chalk River Nuclear Labs.— Experiments by Broude et al1) and by Toulemonde and Haas2) have shown that values of the apparent life­time for the 4+ level in 22fle derived from low initial velocity (v 'U 1% the velocity of light) DSAM measure­ments analyzed using theoretical stopping powers show large systematic variations as a function of the stop­ping material. In the present experiment, the lifetime of this level was determined by producing 22^e recoils at high initial velocities (v ^ 4% the velocity of light) where stopping power measurements exist. The ^(He(l^F,p) 22Ne reaction was used and gamma rays were detected at 0° in coincidence with protons to the 4+ level of 22pje. From the analysis of the Doppler broadened lineshapes of the 4+ -+■ 2+ transition, consistent values of τ = 0.333 ±0.020 ps and τ = 0.315 ± 0.020 ps, for Cu and Au stop­ping media respectively, were obtained. These values should help to resolve the difficulties in interpreting the low velocity measurements.1) C. Broude, P. Engelstein, M. Popp and P.N. Tandon,

Phys. Lett. 39B, 185 (1972).2) M. Toulemonde and F. Haas, Phys. Rev. C15, 49 (1977).

1 5 : 1 5

15:30BD8 Measurements of the Pr oton To ta l React io n Cross

Section f or *»°Ar D.K. HASELL, T.N. NASR and A.M. SOURKES, Cyc lo tron Lab. U n iv e r s i t y o f Man itoba*, R. F. CARLSON and A.J. COX, U n iv e r s i t y of Redlandsr,and D.J.

MARGAZIOTIS, C a l i f o r n ia S ta te U n iv e r s i t y , Los Angeles^ -- Using a t i g h t l y co l l im a ted and momentum analyzed proton beam and a modif ied a t tenua t ion techn ique l) t o t a jR e a c t i o n cross sec t ions , o r , have been measured

fo r Ar a t 23, 29, 36, 43, and 49 MeV. The argon gas was contained in a 3-cm long gas c e l l w i th t h in n icke l

entrance and e x i t windows a t a p ressure o f app rox i­mate ly 1000 kPa. The *t0Ar cross sect ions are presented and compared w i th o p t ic a l model p red ic t io ns and w i th or values measured fo r the nearby elements 40Ca and 48Ti in the same energy reg ion.

it

Work supported in pa r t by the NRC o f Canada

Work supported in pa r t by the Research Co rpo ra t ion, U.S.A.

^ R.F. Car lson, W.F. M c G i l l , T.H. Shor t , J.M. Cameron, J.R . Richardson, W.T.H. van Oers, J.W. Verba, P.

Doherty and D.J. M a rga z io t is , Nucl. In s t . 123. 509 (1975)

BD9 Admixtures of Second-Forb idden Matrix Elements the Isospin-Forbidden beta Decay of 7egRb.*D. M. REIiFIELD, McGill Univ.--The 0 + ( g os. , ’ g . s . ) positron decay of "7'é Rb to78}<r has bee found to deviate from an allowed shape. The shape factor obtained is S(W)=K(l .0.0206V/2 +0.0017W3 ), where W is the positron energy in units of mc^ and K is an (undetermined) multiplicative constant. This shape factor was obtained in a positron energy range of 3 to 6 MeV. The present studies indicate that this transition account for of the decay of 7^£Rb,and has an endpoint energy of 6195^50 keV. The shape factor is attributed to second-forbidd­en matrix elements, and the effect of these admixtures o the effective Coulomb matrix element will be discussed.

* Supported by the Atomic Energy Control Board.

10

MONDAY, JUNE 20, 1977ROOM 127Chairman: D. Matz

PHASE TRANSITIONS

13:30BEI Elastic Neutron Scattering Study of the

Antifluorite Crystal K?OsClf;. D. MINTZ and R.L. ARMSTRONG, Univ. of Toronto, Toronto, Ontario?B.M. POWELL and W.J.L. BUYERS, Atomic Energy of Canada Ltd., Chalk River, Ontario.--The structural phase transition in potassium hexachloro-osmate (K^OsClg) has been investigated at the NRU reactor by elastic neutron scattering methods. The observed change in the crystal structure in passing through Tc is consistent with a rotational model in which rigid OsClfc octahedra undergo a collective ferro-rotation. The transition temperature found from the temperature dependence of the Bragg peaks was 44.5 ± 0.4 K. The transition is continuous with a critical exponent, $ = 0.35 ± 0.06, characteristic of three-dimensional phase transitions.

13:1,5 * BE2 Analysis of Power Series for Critical Exponents.E. W. GRUNDKE, St. Francis Xavier Univ.--An important step in series expansion studies of critical phenomena is the final analysis of the power series to obtain the location and exponent of its dominant physical singu­larity.! A procedure is described which moves the singularity to a known location and then estimates the exponent using a self-consistency criterion. To some extent the strong dependence of the estimated exponent on the estimated location of the singular point is bypassed. Several innovations in the standard tech­niques of Pádé and ratio analysis are also discussed.

1 D. S. Gaunt and A. J. Guttmann, in "Phase Transitions and Critical Phenomena," vol. 3 (ed. C. Domb and M.S. Green). Academic Press (London and New York, 1974)

* Supported by the National Research Council of Canada and the St. F. X. University Council for Research.

I k : 00BE3 Further Investigation of the Classical Vector

Model of Ferromagnetism. P. S. ENGLISH and D. L. HUNTER, St. F. X. Univ. - We have investigated the high-tempe rature series for the free energy and specific heat of the Classical Vector Model of ferro­magnetism in arbitrary spin dimensionality (D). We have extended this series to twelve terms, and have calculated the thirteenth term explicitly for D=3 (the Classical Heisenberg Model). We discuss the conver­gence of this series, laying particular emphasis on the cases D=2 and D=3, and compare our results with previous work1-. Following the Universality Hypothesis, the results for D=2 may be applied to the superfluidity of liquid helium. We also describe preliminary work on the susceptibility of this model through which we expect to obtain a more reliable estimate of the critical point shortly. The present work will then allow us to obtain a more reliable estimate of the specific heat exponent a.

1. M. Ferer; M. A. Moore and M. Wortis, Phys. Rev.B4, 3954, (1971).

114:15BEk Spontaneous Symmetry Breaking in the Large

Dielectric Polaron. D. MATZ, Univ. de Montreal.— We have shown elsewhere how to obtain the large dielectric polaron ground state energy within the Fock Green’s function approximation (with no a priori translational invariance) for all coupling constants, a.1 We found a translationally invariant exact ground state energy solution for a < 3,* and approximate ones for a > 3, corresponding to states which break the symmetries of the Frohlich hamiltonian1*2. Here we show how to obtain the exact polaron Fock wave function in the region 0 < a < 3, confirming explicitly that it is an eigen­state of total momentum with eigenvalue zero. More im­portantly, the wavefunction renormalization constant displays an essential singularity at a = 3, implying that for a > 3 the system exists in a phase of diffe­rent symmetry (perturbation theory also is no longer applicable), a conclusion that is consistent with our previous findings1»2. Similar results hold for the low lying excited states, i.e., small total momentum states.

JD. Matz, Can. J. Phys. 53, 2665 (1975).2D. Matz, Y. Lépine and R. Simard, submitted for publi­cation.

XÍ4 :30BE5 Anharmonic Phonons in Potassium.* H.R. GLYDE,

Univ. of Ottawa, M.L. KLEIN, National Research Council of Canada, and J.-P. HANSEN, Univ. of Paris Vl.-Calcu- Lations of the phonon frequencies and lifetimes in K at T= 162.5 K and T = 311°K using both the self consistent theory of dynamics and direct molecular dynamic simula­tion have been made. These show that while the self consistent theory represents anharmonic effects well in simple metals such as K, there remain small errors, particularly in the phonon lifetimes, near the melting point. Comparison of both calculations with recent measurements^· on K via neutron inelastic scattering have also been made and show excellent agreement.

^J. Meyer et al, J. Phys. F. 6, 943 (1976)*Supported by the National Research Council of Canada.

15:00BE6 Positron Self-Trapping in ^He . E. ZAREMBA and

M.J. STOTT, Dept, of Physics, Queen's Univ.— Positron annihilation experiments in helium gas have shown anomalies in annihilation rate near the gas-liquid critical point which indicate the formation of positron self-trapped states in helium droplets. A theory is presented which appears to confirm the existence of the self-trapped states and accounts quantitatively for the positron annihilation rate in the range of densities and temperatures over which these states are stable. A thermodynamic potential describing the interacting positron-helium system is constructed and a variational method is used to obtain the positron wavefunction and helium density distribution. The stability of the drop­lets arises from the net attractive positron-helium atom interaction and the easy compressibility of the gas near the gas-liquid critical point. The droplets have a maximum density 2.2 x 1022cm” and are typically 15Â to 25Â in radius.

*Supported by the National Research Council.

11

BE7 Vacancy Formation Enthalpy Measurements in the Brass System. P. J. SCHULTZ, T. E. JACKMAN, J. FABIAN, J. R. MacDONALD and I. K. MacKENZIE, Univ. of Guelph. Doppler broadening measurements of the annihilation line in the Cu-rich half of the Cu-Zn system are analysed by a threshold temperature technique to show the systematic dependence of the formation enthalpy on concentration and crystal structure. Evidence is found for structural vacancies at low temperature in the neighbourhood of the β' phase, the associated well depth being much less than that of the non-structural vacancies generated in the same material at higher temperature.

15:15

15:30be8 A Magne t ic and Mossbaue r Study o f Magnetic

Order ing and Vacancy C lu s te r in g in CuçFeS/i

M.G. TOWNSENDt and W.B. MUIR*

Magnetic s u s c e p t i b i l i t i e s and Mossbauer spectra recorded

at temperatures between 4° and 300°K show th a t the low temperature form o f Cu5 FeS4 , b o rn i t e , orders magnet ica l­l y a t 76±20K. At a lower temperature 8°K a second magnetic phase t r a n s i t i o n occurs. The Mossbauer spectra

suggest t h a t the re is s i g n i f i c a n t p a r t i a l d iso rde r ing o f cations and vacancies in te t ra hed ra l holes o f the

face-centred cubic su lphu r l a t t i c e . The rmoe lec tr ic power measurements in d ic a te t h a t bo rn i te i s a p-type semiconductor.

MONDAY, JUNE 20, 1977 ROOM 126

Chairman: T.K. A lexander

13:30BF1 Timing Properties of HPGe Detectors* B. C.

ROBERTSON, A. BROWN, Queen1s University and U. L. MALM, Aptec Engineering Ltd.— The dependence of a coaxial HPGe detector timing characteristics on detector bias has been determined. Pulse shape characteristics as a function of bias are compared with those of a Ge(Li) detector, and with calculated pulse shapes obtained using a simple model of the pulse generation process in HPGe detectors. The HPGe detector exhibits improved timing performance because of electric field modifica­tion due to the fixed space charge present.

*Work supported in part by the National Research Council Canada.

13:145BF2 Response F u n c t i o n s o f I n t r i n s i c

German ium- D e t e c t o r s to t i e c t r o n s ana

P o s i t r o n s * W.R. LEO and K. MUUKt, M c G i l l U n iv .~ - T h e use o f an i n t r i n s i c ge rm an ium c r y s t a l d e t e c t o r f o r t h e m easu rem en t o f h ig h n u c l e a r b e ta d ecay e n e r g i e s r e q u i r e s s p e c i f i c

kno w led g e o f t h e r e s p o n s e f u n c t i o n s o f th e d e t e c t o r i n o r d e r to a l l o w u n f o l d i n g o f th e o b s e r v e d p u l s e h e i g h t d i s t r i b u t i o n s . We have c o n s t r u c t e d a Mon te C a r l o p ro g ram w h ic h

c a l c u l a t e s t h i s r e s p o n s e f o r e l e c t r o n s and p o s i t r o n s i n t h e 1 to 10 MeV ra n g e . The p rog ram f o l l o w s t h e e l e c t r o n s and p o s i t r o n s t h r o u g h t h e ge rm an ium c r y s t a l and keeps t r a c k

o f t h e e n e rg y d e p o s i t e d i n t h e c r y s t a l . The

For a th ree dimensional magnetic superexchange i n t e r ­ac t ion between F e ( I I I ) atoms a small supe r- t ransfe r red

spin dens i ty would be requ ired on in te rm ed ia te Cu( I) atoms.

tEMR, Ottawa, K1A 0G1

*McGil l U n iv e r s i t y , Montreal

15:U5V e l o c i t y o f U l t r a s o u n d I n TTF-TCNQ C r y s t a l s . M.H.

JERICHO, W .A . ROGER and A. SIMPSON, D a l h o u s i e U n i v . - ­

We have m easu red t h e v e l o c i t y o f 10 MHz u l t r a s o n i c p u l ­

ses w h ic h w e re p ro p a g a te d a l o n g t h e b - a x i s o f TTF-TCNQ

c r y s t a l s . The v e l o c i t y o f l o n g i t u d i n a l t y p e modes i n ­

c r e a s e s by a b o u t 2ζ% on g o in g f ro m room t e m p e r a t u r e to

AK and th e v e l o c i t y c u r v e s show a s h a rp k i n e k n e a r 52K.

The m a g n i t u d e s o f t h e v e l o c i t i e s a r e r e a s o n a b l y c o n s i s ­

t e n t w i t h h e a t c a p a c i t y m e a s u re m e n ts 1 b e lo w AK and we

c o n c lu d e t h a t TTF-TCNQ does n o t d i s p l a y a n y u n u s u a l

e l a s t i c a n i s o t r o p y . W i t h t h e h e l p o f i n f r a r e d a b s o r p t i o n

m e a su re m e n ts 2 we have c o n s t r u c t e d a s p e c i f i c h e a t f u n c ­

t i o n f o r TTF-TCNQ and c o n c lu d e t h a t t h e b - a x i s t h e rm a l

e x p a n s i o n i s d o m in a t e d by i n t r a m o l e c u l a r modes. We f u r -

t h e r e c a l c u l a t e d t h e T dependence o f t h e b u l k m o d u lu s , B,

and a co m p a r i s o n w i t h t h e v e l o c i t y r e s u l t s s u g g e s t s t h a t

t h e p r e s s u r e d e r i v a t i v e o f B, dB/dP - 15. The e x t r a

s t i f f e n i n g o f t h e e l a s t i c m od u lu s b e lo w 52K i s a t t r i b u ­

te d t o t h e c h a rg e - d e n s i t y - w a v e t r a n s i t i o n and we s u g g e s t

t h a t i t r e f l e c t s th e v a r i a t i o n o f t h e g ro und s t a t e e n e r ­

gy o f TTF-TCNQ as t h e c h a r g e - d e n s i t y - w a v e s t a t e i s

es tab 1 i s h e d .

1T .W e i , e t a l , P h y s . L e t t . A5A, 269 (1973 )

2 J . E . E 1 d r i dge, S o l i d S t a t e Commun. 19, 607 (1976 )

NUCLEAR INSTRUMENTATION AND TECHNIQUES

p o s s i b i l i t y o f p a r t i a l e n e rg y d e p o s i t i o n due t o b a c k s e a t t e r i n g and B r emst r a h 1ung escape

i s a l s o t a k e n i n t o a c c o u n t . R e s u l t s and a s h o r t d i s c u s s i o n w i l l be p r e s e n t e d .

♦ Resea rch s u p p o r t e d by t h e N a t i o n a l R e s ea rc h

C o u n c i l .

1A : 00

BF3 An Improvement to the Beam Buncher o f the U n iv e r­s i t y o f Manitoba Cyc lo tron^ . R. P0GS0N and S. OH, CycTo-

t ro n Lab. Univ. o f Manitoba -- In March 1976 the e x t r a c t ­ed cu r ren ts a v a i l a b le from the U n iv e r s i t y o f Manitoba Cy­c lo t ro n were increased nea r ly 4021 by the ad d i t io n o f a

second harmonic component to the s inuso ida l waveform pre­v io u s ly used on the beam buncher. The d r iven element of the two gap beam buncher was b isected and the two halves are now d r iven in push-pull mode a t the second harmonic and in p a r a l l e l mode a t the fundamental frequency. With t h i s technique the two frequencies a re never mixed and can be co n t ro l le d independent ly in phase and ampli tude. The e le c t ro n ic system is simple in comparison to t h a t used a t K a r ls r u h e ) ). I t cons is ts o f an antenna to pick up the cyc lo tron frequency, an a m p l i f i e r which could be

e l im ina ted by inc reas ing the antenna coup l ing , a s ignal s p l i t t e r , a passive frequency doub le r , two de lay boxes, two a t tenua to rs and th ree tuned c i r c u i t s .

G. Haushahn e t al , Seventh In te rn a t io n a l Conference on Cyc lo trons and T he i r A p p l ic a t io n s , page 378.

*Supported by the NRC o f Canada.

12

l l i t lSBFl* The M cG i11 C y c l o t r o n U p g ra d in g

P r o j e c t . * J . E . CRAWFORD, R .B . MOORE and G .K . B AVAR IA , M c G i l l U n i v . --The M c G i l l p r o to n s y n c h r o c y c l o t r o n has r e c e n t l y been m o d i f i e d to

a c c e l e r a t e io n s w i t h c h a rg e - to - m a s s r a t i o s o f 2 /3 and 1 /2 . A new dee has been i n s t a l l e d ,

and t h e c o a x i a l r a d i o - f r e q u e n c y l i n e s have been m o d i f i e d to p e r m i t r a p i d c h a n g e o v e r b e tw een f r e q u e n c y r a n g e s c e n t r e d on 24 , 16 and 12 MH^.

The d e s ig n p ro c e d u re f o r t h e new s y s te m w i l l be

d i s c u s s e d , and p r e l i m i n a r y m e asu rem e n ts o f t h e p e r fo rm a n c e o f t h e s y s te m w i t h ^He and 4He i o n s w i l l be p r e s e n t e d .

‘ R e s e a rc h s u p p o r t e d by t h e N a t i o n a l R e s ea rc hC ounc i 1.

114:30BF5 A Readout system for dual coordinate

multiwire Proportional Chambers*, L. BIRD,R.G. FINDLAY, R. SANCTON, Carleton University.- A readout system for the induced planes of dual coordinate multiwire proportional chambers is described. The X and Y coordinates are cal­culated in a C.A.M.A.C. unit and stored for subsequent transfer to the computer.

‘Supported by N.R.C. (Canada) through the Institute of Particle Physics.

MONDAY, JUNE 20, 1977 ROOM 107

Chairman: H.R. Glyde

POLICIES FOR SCIENCE AND TECHNOLOGY IN CANADA

20:00BG1 THE HONOURABLE J. HUGH FAULKNER

MlnnAten o i State, ion. Science and Technology

20:30BG2 J.J. SHEPHERD

Executive V inecton , Science Council ok Canada

lU : U5BF6 MANSA - MANitoba S imu la t ion and Ana lys is Pro»

gram.* T. W. MILLAR and J. V. JQVANOVICH, Univ . o f Ma~-

n i to b a .-- MANSA is a general event s im u la t io n and data

ana lys is program fo r mult i-arm spectrometer experiments. The program is w r i t t e n in a modular ( k i t ) form so i t

can be e a s i l y expanded, contracted o r changed. Program

users th a t a re not in te res ted in some s o f i s t ic a te d op­

t ions e x is t in g in the program can use i t in i t s elemen­t a r y form on ly .

The general o rgan isa t ion o f the MANSA program

w i l l be discussed and r e s u l t s o f some app l ica t io n s w i l l be presented.

•Supported by the Nat ional Research Council o f Canada and the U n iv e r s i t y o f Manitoba through a computer g ran t.

15:00BF7 Transmission of Electrons in a Scattering

Medium*. W.R. CONKIE, Queen's Univ.— A transport theory of electron propagation in finite multi-media problems has been developed in a form suitable for application to radiation detectors. The theory is based on a com­bination of Bethe's theory of multiple scattering1 and Spencer's basic work on electron transmission in in­finite media2. Simple expressions for angular moments S. > 2 can be obtained, followed by numerical solution of the equation for the electron flux and current. Comparison will be made with experimental results of Seliger3 and others.

'h .A. Bethe, Phys. Rev. 89, 1256 (1953).2L.V. Spencer, Phys. Rev. 98, 1597 (1955·3H.H. Seliger, Phys. Rev. 100, 1029 (1955).•Supported by Atomic Energy of Canada Ltd.

PHYSICS AND SOCIETY

21:00 Discussion and Questions from the Floor

Chairman: B. Ahlborn

TUESDAY, JUNE 21, 1977ROOM 130 PLASMA PHYSICS SYMPOSIUM

9:00CA1 Dynamic Stabilization of Microinstabilities

J. TEICHMANN, UrUviAi-iXí d l Mo n t â i a l

Electromagnetic fields generated by external sources penetrating into a plasma can change the dielectric properties of plasma substantially. Thus, growth rates, thresholds and frequencies of microinstabilities driven by density and temperature gradients, impurity ions and anisotropy in the particle distribution in velocity space, could be strongly influenced if a suitable configuration of the H.F. field components is chosen. A review of theoretical work on this subject will be presented. Also discussed will be recent experiments, especially these based on use of a low impedance H.F. field for suppression of drift-dissipative instabilities.

9:45CA2 Evaluation of Magnetoelectric Traps for Hot Plasma Confinement

B.C. GREGORY, ÍWRS - EnesigZe

10:30CA3 Nonlinear Laser Plasma Interaction Experiments

A.A. OFFENBERGER, Ün-LVZ/iA^ty 0 f A lb&Ua

The in te ra c t io n of high power la s e r r a d ia t io n w ith plasma provides a r ic h source of non l inear

phenomena, espec ia l l y through coupling to natura l plasma modes. Stimulated sca t te r ing and abso rp t ioncan occur,which are of fundamental importance to e f f i c i e n t coupling of la se r power to plasma in in e r t ia l l y - c o n f in e d fus ion schemes. Here, we repo r t on de ta i led experiments designed to in ve s t ig a te such non l inear coupling in a we l1-diagnosed plasma.

11:15CA4 Scattering and Harmonic Generation in High Intensity CO_ Laser Heating Experiment.

N.H. BURNETT, WatcrmaX Rc4eaAc/i C o u n c il o f Canada

TUESDAY, JUNE 21, 1977 MAGNETIC RESONANCEROOM 103Chairman: R.L . Armstrong

9:00CB1 Nuclear Spin Polarization Torsional Spectroscopy in Solids

M.M. PINTAR, ÜtU.ue/lA'ttÿ o f WoXqaZoO

If Zeeman spin states at a low temperature are matched to a pair of torsional levels at higher temperature, a resonant transfer of order occurs. Observations of such instantaneous resonant loss of spin polarization in solids have been made at very small fields (corresponding to torsional energy splitting of 'v 10-ι< peV). Measurements yield a part of the torsional spectrum and, if performed at small fields, also the torsional relaxation time. The experimental technique is to precool instantaneously the spin system in the rotating frame to about 0.1 K by application of a π/2 r.f. pulse followed by a phase shifted r.f. field pulse. This new spectroscopy at high fields and in the rotating frame will be discussed on the basis of spin thermodynamics.

9:1*5CB2 Nuclear Spin Conversion Processes In Solid

Methane*" R.F. CODE, J. HIGINBOTHAM and B.M. WOOD, Unlv. of Toronto.— The time dependence of the proton nuclear spin conversion in solid methane below 20.4 K has been determined by an NMR polarization experiment. Samples of 13CHt, containing variable trace amounts of oxygen impurities were observed for periods of up to 80 hours at 1.8 K during their final approach to equilibrium. As anticipated by earlier work1, a clear separation of the spin conversion processes on the two types of orienta­tional sublattices was obtained. The results will be compared to the recent model of spin conversion propo­sed by Nijman and Berlinsky^.

1. R.F. Code and J. Higinbothara, Can. J. Phys. 54 1248 (1976). 2

2. A.J. Nijman and A.J. Berlinsky, Phys. Rev. Letters, 38 408 (1977).

*Work supported by the National Research Council of Canada.

10:00CB3 Nuclear Spin Relaxation and Activation Energies

of Tunnelling Methyl Groups* P A BECKMANN** and S CLOUGH Univ of Nottingham — The temperature dependence of the proton spin lattice relaxation time from 6 to 50 K is reported for three samples containing methyl groups whose tunnelling frequencies are well known. They are 4-methyl-2,6-ditertiarybutylphenol (MDBP) and two deut- erated derivatives. The activation energy measured at temperatures between 18 and 50 K is in good agreement with the splitting between ground and first excited methyl group torsional states, as computed from the known tunnelling frequencies assuming a three-fold hind­ering potential. At temperatures below 15 K the obser­ved activation energy is only about half this value and it is suggested that this is due to the coupling of short wavelength lattice vibrations with the methyl group rotational motion.

* Supported by the Science Research Council (UK)

** National Research Council of Canada PostdoctoralFellow, 1975-77. Present address: Physics Department, Univ of British Columbia.

ih

10:30CBl* Sensitivity in SQUID Ma gne tome ter Detection of

N.M.R. J.L.G. LAMARCHE, M. O'CONNELL and G. GOODCHILD, Univ. of Ottawa.-A SQUID magnetometer is used to detect N.M.R. by recording the d.c. nuclear magnetization Mz parallel to the direction of a constant applied magnetic field B0 . The slow passage signal is largest when the resonance effect is saturated by the r.f. power incident on the sample, but the optimum signal-to-noise ratio of the SQUID and related electronics introduces a severe limit as to what nuclei can be observed. The relative sensitivity of the method for equal number of nuclei of species i and of protons p is given by

2 2y. (I.+1}I /p_ (I +1)1. for the constant field case. By 1 1 Ÿ Y P 1comparison with known signals, the s/n ratios to be expected for all nuclei can be estimated. Only a small fraction of all isotopes gives a value greater than one. Methods to enhance the signal will be discussed: lower temperatures and higher fields. Also, signal averaging techniques will be assessed. Experimental results will be given to illustrate some aspects of the sensitivity of this method of N.M.R. detection.

10:U5CB5 Laser Magnetic Resonance of HCO at 9.Up.

J.W.C. JOHNS, A.R.W. McKELLAR and M. RIGGIN, Herzberg Inst, of Astrophysics, NRCC, Ottawa— The v2 bending fundamental of the formyl radical HCO (vo = 1080.76 cm 1) has been studied by the laser magnetic resonance technique using a C02 laser at 9.*+M. Fluorine atoms from a discharge in CFi» were reacted with H2C0 to form the HCO, which flowed through an absorption cell located between the pole faces of an electromagnet and within the optical cavity of a C02 laser. Over 200 Zeeman resonances involving levels with H£7 and Kal3 have been detected and assigned, enabling accurate estimates of the band origin and the rotational, centrifugal distortion, and spin rotation interaction parameters of the V2=l state to be made. Fairly large changes in the values of A, Δκ , and between the ground and v =1 levels were observed.

11:00CB6 Μ-Dependence of Colllsional Transfer of

Rotational Energy in PCS.* R. M. LEES, Univ. of New Brunswick— Collision-induced transitions have been investigated by microwave double resonance for OCS in the v=0 ground state, with the M-sublevels separated by a Stark field. Experiments have so far been perfor­med on the (2*-l>p-(l«-0>s and (3+2)p-(l*-0) s systems for pure OCS and for mixtures with CH30H, He and H2· For Δμ =0 in the second system and Δμ =1 in the first, parity-changing (dipolar) collisional transitions are preferred in OCS-OCS and OCS-CH3OH collisions, while parity-conserving (non-dipolar) transitions are preferred in OCS-He and OCS-H2 collisions. For ΔΜ=2 in the second system above, parity-conserving transitions are observed for all collision partners.

*Supported by the National Research Council.

11:15CB7 Radiofrequency Spectroscopy of Methyl Iodide

Inside a Laser Cavity. E. ARIM0ND0, P. GLORIEUX andT. OKA, Herzberg Inst, of Astrophysics, Ottawa --------The infrared-radiofrequency double resonance is used to observe "pure" quadrupole transitions (AI=AJ = AK = o and AF = ±1) of CH3I in the 1-500 MHz region. The sensitivity of the intracavity method is several orders of magnitude larger than that of the straight RF absorption method and quadrupole resonances in many vibrational and rotational states have been observed.The characteristic pattern of the rf spectrum specific to each rotation vibration level has enabled us to assign the infrared coincidence and the associated far- infrared laser transitions unambiguously. This also provides the dependence of the quadruple coupling constants with rotation and vibration quantum numbers, the spin-rotation and 1-type doubling constants.Several phenomena have been observed and interpreted. They are (1) infrared radiofrequency Lambdips (2) radiofrequency two photon signals and (3) collision Induced double resonance signals. The last phenomena provide nature of rotational energy transfer in CH3I, This method of observing "pure" quadrupole transitions in gases is applicable to any polar molecule having rotational levels with double parity.

TUESDAY, JUNE 21, 1977 ACCELERATOR PHYSICSROOM 202

Chairman: D.W. Smell ie

9:00CCI The Electron Pulse Stretcher Ring EROS and Its Applications

R. SERVRANCKX, U rU v eiu lty S a ska tch ew an

9:45CC2 The Spallation Breeder of Fissile Material

J.S. FRASER, Chalk ZiveA Nucleon. Labonatonles

10:45CC3 Chalk River Superconducting Heavy Ion Cyclotron

j .h . ORMROD, Chalk RiveA Nuclea/i LabonatosUes

11:30CC4 Applied Physics at TRIUMF

E.w. BLACKM0RE, TRIUMF, UnlveAAlty BnÂJttsh Columbia

BIOPHYSICS

Chairman: A.F. Holloway

TUESDAY, JUNE 21 , 1977ROOM 126

9:00CD1 The Origin of Nuclear Spin Relaxation in Tissues H. PEEMOELLER, L.J. SCHREINER and M.M. PINTAR, Dept._of Physics, Univ. of Waterloo— Measurements of proton spin-lattice relaxation in the laboratory and rotating frame and of spin-spin relaxation times have been made in normal and in isotonic 100% and 60% deuterated mouse tissues. Field and temperature de­pendences of the above relaxation times are used to es­tablish the existence of a strong intermolecular diffu­sion relaxation of water protons. Because this process, which has a similar frequency dependence as the intra­molecular reorientational relaxation, it is difficult to use spin relaxation times for tissue characterization. The freezing phase transition and motion of water mole­cules in tissue are analized on the basis of a more general relaxation model.

9:15Perturbed directional correlations of gamma-ravs

emitted by Meta1 ions in bovine Carbonic Anhydrase.G.R. DeMILLE, K. LARLEE, D.L. LIVESEY and K. MAILER. Univ. of New Brunswick— Measurements are reported on the perturbed directional correlations of gamma-rays emitted by 133Ba and Ulln sources added to apo-carbonic anhy­drase in aqueous solution. Interpretation of the re­sults depends critically on the nature and the degree of binding between metal ions and the enzyme molecule, also on the effects of Auger emission following electron cap­ture by T3 3ga an<3 111χη. The binding problem has been investigated by ultra-violet differential spectroscopy and enzyme assay methods, leading to the conclusion that indium binds strongly to apo-carbonic anhydrase, prob­ably in the molecular site normally occupied by zinc. However, barium ions appear to bind weakly and in a non­specific fashion, a deduction supported by the nuclear evidence. Clear evidence has been obtained of pertur­bations of the gamma-ray correlation pattern in indium bound to the enzyme. The experimental time-differential spectra are interpreted in terms of a component due to Tiled daughter-ions bound to the slowly-rotating enzyme molecule plus a component with a short rotational correlation time, ascribed to the after-effects of Auger emission following electron capture.

9:30CD3 A High Resolution Energy Selecting Electron Mi­

croscope . J.W. ANDREW and F.P. 0TTENSMEYER, Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto. - -Light microscopy of biological tissue has benefited im­mensely from the use of light optical stains of differ­ent specificities and colors. Although these stains are highly specific, they could not be used in electron microscopy since electron microscopes with energy fil­tering capabilities were not available and contrast in electron microscopy has therefore had to rely on heavy atom stains. We have designed an imaging spectrometer for a Siemens 102 electron microscope, operating at ac­celerating voltages of 20 to 125 kV, which should be capable of utilizing the light optical stains. Filtered images using electrons which have lost energies from 0 to 4500 eV in the specimen can be obtained with an energy resolution down to 1.5 eV. The deleterious ef­fects of chromatic aberration found with thicker specimens can be obviated, opening up new analytical capabilities for both metallurgical and biological specimens.

9:^5CDA An Improved Prism Design for an Energy Selecting

Electron Microscope. F.P. OTTENSMEYER and J.W. ANDREW, Ontario Cancer Institute and Department of Medical Bio­physics, University of Toronto. - -Energy selecting electron microscopes of the Castaing- Henry prism-mirror-prism type (see previous paper) suffer from a loss in image resolution with increasing field of view. Experiments with a prototype of such a device indicated that an image premagnification of 1000 before the image is filtered permits a useful field of view of about 1μ diameter. The resolution, which was 6) for this instrument at the center of the field of view, worsened very rapidly beyond this 1μ limit. These aberrations result primarily from the different focusing effects of the fringe field on electrons emerging from the intermediate lens cross over and entering the prism at slightly different angles of attack. We have been able to correct these aberrations to first order by designing a prism with curved, rather than flat, en­trance and exit surfaces. This should allow for up to an order of magnitude increase in the useful field of view.

10:00CD5 Visual Perception Limits in Angiography.*

A. E. BURGESS and k 7 HUMPHREY, Univ. of B.C. --Two different types of psychophysical experiments were performed. The first was done using large numbers of images of aluminum wires produced by a standard neuro­angiography system. Wire diameter at the statistical detection threshold was determined as a function of geometric magnification and quantum noise level. The results were compared to predictions of a number of signal to noise ratio (SNR) theories. The second set of experiments were done by optically superimposing targets on a variety of backgrounds (noiseless,quantum and/or structural noise). Results for a variety of target sizes and shapes will be presented and inter­preted using a simple SNR theory. A novel effect due to variation in decision criteria will be described.

*Supported by the B.C. Health Sciences Research Fund.

10:145 .cd6 D e s ig n and P e r f o rm a n c e o f a Medic a 1

L in a c R a d i a t i o n M o n i t o r / C o n t r o ι i e r . l .D. MÔLSÛN, D .L . SMYTH and W.K. BROWN, A tom ic E n e rg y o f Canada L t d , -- A t r a n s m i s s i o n t y p e ,

p u l s e d - r a d i a t i o n , m o n i t o r has been d e v e lo p e d to p r o v i d e t h e T h e ra c 6 /N e p tu n e t h e r a p y a c c e l e r a t o r w i t h r e l i a b l e p ho to n r a d i a t i o n

c a l i b r a t i o n as w e l l as i n f o r m a t i o n used by beam s t e e r i n g s e r v o s y s te m s to m a i n t a i n a s y m m e t r i c r a d i a t i o n f i e l d . The m o n i t o r i s a d o u b le io n chamber a s s em b ly w i t h one chamber d e d i c a t e d to m o n i t o r i n g t h e f u l l p ho to n beam

o u t p u t , and t h e o t h e r used to i d e n t i f y beam a s s y m m e t r y . The m o n i t o r i s f a b r i c a t e d u s in g p r i n t e d c i r c u i t b oa rd m a t e r i a l w i t h e l e c t r o d e

d e s ig n s c o m p a ta b le w i t h t h e T h e ra c 6 a p p l i ­c a t i o n . S t a b i l i t y o f t h e m o n i t o r c a l i b r a t i o n i n p ho ton r a d i a t i o n f i e l d s i n e x c e s s o f

1200 R / m in u te i s b e t t e r t h a n 21. Chamber c o l l e c t i o n e f f i c i e n c i e s have been m easu red and r a d i a t i o n damage s t u d i e s on t h e chamber

i n d i c a t e l i f e t i m e s i n e xce ss o f 1 0 9 rads for the monitor.

16

THE USE OF A HAND-HELD PROGRAMMABLE CALCULATOR FOR DOSE CALCULATIONS IN RADIOTHERAPYL.H.Gerig,J.C.F.MacDonald and D.J.Dawson, Ontario Cancer Foundation, London, Ontario,

The treatment time or number of monitor units must be calculated In order to carry out the prescription of a dose at the specified depth and field area. It has proved possible to express in analytical form the dependence of relative dose on depth and area and to describe it in a program of about a hundred steps. Such a program, unique to a particular therapy unit, can be stored on a magnetic strip memory used in programming a hand-held calculator. This has been done for a betatron, a linac, and a cobalt unit, with a single calculator serving all three. The strip for the specific unit is inserted into the calculator, and when the depth, tne area, and the required dose are keyed in, the program yields the required number of monitor units (linac and betatron) or the treatment times (cobalt unit). Corrections for wedge filters and shielding blocks can also be included.

11:00CD7

11! 15CD8 Dose Distributions Around Radium Arrays Used

In The Treatment of Uterine CancerP .D . SHARMA, ONTARIO CANCER FOUNDATION THUNDER BAY C L IN IC , THUNDER BAY, ONTARIO

The determination of absorbed dose in gynecological applications of radium is more difficult and less accurate than in any other branch of radiation oncolo­gy. This inaccuracy is inherent in a technique which involves using linear sources at short distances, where inverse square law variation is manifested in sharp dose gradients. Despite the advent of the electronic computer and the consequent improvement in the determination of dose distributions, there are still many variables involved, not the least of which arises in the estimation of the positions and shapes of the relevent organs.In this work a determination of the dose distributions around a number of reconstructed radium applications was made using LiF microrods. The results of these measurements were then compared with those of computed dose distributions of the same radium arrays. Taking into account the uncertainties inherent in both procedures, the agreement was good.

TUESDAY, JUNE 21 , 1977 ROOM 128

Chairman: J.-D. Carette

9:00CEI High Resolution Raman Spectroscopy of Gases

H.L. WELSH, UnivQAà'iX y 0 ToKOYVto

9 'MX-Ray Scattering by Liquid Argon at High

Pressure.* K. L. YAN and J. C. STRYLAND, Dept, of Physics, Univ. of Toronto.— The molecular ordering in liquid argon is studied as a function of pressure and temperature. Scattering of a highly monochromatic and collimated X-ray beam takes place off a sample contain­ed within a cylindrical beryllium cell of 1.0 mm i. d. and 2.54 mm o. d. The scattered intensity is measured by a photon counter, moved in steps of 0.125 degree. A total of approximately 500 hours counting time provided

CD9 Evaluation of Radiation Risks from the radioactive tracers in sediment transport studies. N. KULKARNI, Halifax Infirmary and B. LONG, Bedford Institute of Oceanography. This paper discusses the application or critical path techniques to the evaluation of public radiation exposure from the marine release of radioactive tracers. Precision and economy are the advantages of the use of tracer in sediment transport studies. Radiation exposure risks to the population must be known before its release. The evaluations have been compared with the measurements done during the investigations at the MINAS BASIN. Various factors such as the radioisotopes, total activity and activity per grain of the sand,to be considered in the application as well as risk evaluation have been discussed.

11:30

11 : h 5UD10 The Use of Phoswich Detectors in the Radiation

Protection Bureau Human Monitoring Laboratory. C. Pomroy, Radiation Protection Bureau, Department of National Health & Welfare - A recent development in scintillation counters is the phoswich detector, which consists of a double crystal of two different materials with different scintillation characteristics. The associated electronics is able to distinguish between events in the two crystals, and anti-coincidence counting then enables the background count of the detector to be significantly reduced in the low energy (below lOOKev) region. The Human Monitoring Laboratory of R.P.B, has used three of these detectors for a variety of health physics studies. The first was to develop a method for in vivo measurements of 2^9pu the lungs. The Laboratory participated in an inter­national calibration experiment using volunteers whose lungs were loaded with ^^Pd. A series of measurements were made to investigate the effects of detector location, subject position, and body build. Another use of these detectors has been in the investigation of uranium miners, where ^Pb in the skeleton is thought to be related to total intake of radon daughters. Several miners from a Canadian uranium mining area have been measured. Other uses of the phoswiches include monitoring of laboratory personnel for 2 - -Am and

MOLECULAR PHYSICS

sufficient data for meaningful statistical analysis of one thermodynamic state, a density of 1.427 g/cm^ at 105.4 K. The resulting radial distribution function shows good agreement with Verlet’s 1 computed curve based on molecular dynamics simulation of a system of 864 particles, interacting through a Lennard-Jones (6:12) potential.

*Verlet, L., Phys. Rev. 165, 201 (1968).

*Supported by the Nat. Res. Council of Canada.

17

10:00CE3 The Ravieigh-Brillouin Spectrum of

Compressed He, Ne and Ar. A. D. MAY and V. GHAEM-MAGHAMI, University of Toronto.-~Th Ray­leigh-Brillouin spectra for light scattered at 90° vas observed for He, Ne and Ar at pressures varying from 2 to 100 atm. all at room tempera­ture. The range of densities covers the kinet­ic and hydrodynamic regimes. Of special interest in this work is a check of the usual scaling laws1 for the Raylei,h-Brillouin spectrum. A preliminary analyses shows that the conventional scaling, which loosely speaking is associated with the assumption of a single collision cross-section, does not hold. This is shown purely from an intercomparison of the experimental results for the three gases. The observations will also be compared with a number of theoretical spectral profiles and the scaling laws discussed.lc.f. Fookson et al. , J. Chem. Phys. 65 ,

350 (1976). "

10:30CEU Intensity Measurement of 0-2 Band of CO.

G. CHANPRAIAH, Memorial Univ. of Newfoundland.-- Ourearlier experiemnts on the intensitv measurements of a few higher J-value lines of P-branch 0-2 hand of on have now been extended to lower J-value lines Used in this investigation was the Perkin-Flmer Model PPG double pass grating spectrometer with a spectral slit width of about 0.23-0.25cm ^ Depending on the particular band line being measured, absorption cells of different path lengths and several pure CO gas pressures below 1 atmosphere were used. Line intensities were obtained after making wing and base corrections for the measured equivalent widths. Bv using all the measured line intensities data and the Herman-Wallis formula, the carbon monoxide 0-2 band intensity was calculated. The value found for the band intensity from this method is in excellent agreement with the corresponding value of 2.11 cm 2 Agt-1 obtained by employing essentially the Milson-Wells extrapolation technique.

Chandraiah, CAP-APS-SMF Joint Congress, 1Q76 Université I.avel, Ouébec.

10:1(5CE5 The Rotation-Vibrational Raman Spec­

trum of Benzene.* A. H0LLINCUR and H. L. WELSH, Univ. of Toronto.--The rotation-vibrational Raman spectrum of benzene vapour (80 Torr) has been investigated at high resolution using a multiple-reflection Raman tube and Ar+ laser excitation. All seven Raman-active fundamen­tals were observed, although their structures were only partially resolved. The analysis of these bands will be illustrated by examining

the doubly degenerate Vi7 (e2g) fundamental in which approximately 150 maxima were observed. The molecular constants of this band have been obtained by computer simulation of the band profile. Although, many features of the band can be explained by assuming that the molecule in both the v = 0 and Vi7 = l states is planar, the band frequencies are best reproduced by assum­ing that the inertial defect, Δ i = Ii - 2li, is nonzero in the v17 = l state; the vaTue of Δi/IB v 2x10“3.

‘Supported by the National Research Council of Canada.

11:00Emission Spectra of the d 1Σ*—c1Π and d 1 Z^-b1 Σ*

System of NH. W.R.M. GRAHAM and H. LEW, Herzberg Inst, of Astrophysics, NRCC, Ottawa.— Earlier work1 on the Δν-O sequence of the d'L'-c'lI system of NH and ND in the 2460-2560 Â region has been extended to include higher vibrational levels and transitions with Δντ0. These observations have permitted the determination of accurate vibrational constants for the d*2' and c1Π states. Clear breaking-off in the rotational structure due to predissociation has provided revised estimates of dissociation energies. The system of NH,which previously had been observed only weakly in the 168O-IT8O A region, 2 has now been analyzed in detail.

‘F.L. Whittaker, Proc. Phys. Soc. 90, 535 (1967).2F.L. Whittaker, Can. J. Phys. 47. 1291 (1969).

11:15CE7 Absorption in CO., a t Elevated Temperatures.

A.M. ROBINSON, Univ. o f A lb e r ta - The absorpt ion of 10pm

r a d ia t io n by CO,, and CO mixes has been measured in the

temperature.range 300-650 K over the P and R branches of

the ΟΟ'Ί-ΚΓΟ t r a n s i t i o n . A simple two-level t r a n s i t i o n model of CC does not adequate ly e xp la in the observed

v a r i a t io n of absorp t ion and con t r ib u t io ns from o the r over lapp ing t r a n s i t io n s which become s ig n i f i c a n t a t higher temperatures must be considered. These mixed­mode computations are compared w i th the measured

r e s u l t s .

TUESDAY, JUNE 21, 1977 STRUCTURE OF HEAVY NUCLEIROOM 107Chairman: J.S.C. McKee

9:00CF1 N u c l e a r L e v e l D e n s i t y w i t h R e a l i s t i c

I n t e r a c t i o n s . * F .N . CH0UDHURY and S. DAS GUPTA, M c G i l l U n i v . - - A f o r m a l i s m i s d e v e lo p e d w h ic h can be used to c a l c u l a t e n u c l e a r l e v e l d e n s i t i e s w i t h r e a l i s t i c i n t e r a c t i o n s . The g rand p a r t i t i o n f u n c t i o n and t h e l e v e l d e n s i t y e x p r e s s i o n a r e d e r i v e d f o r t h e g e n e r a l case o f

an a r b i t r a r y s e t o f s i n g l e p a r t i c l e e n e r g i e s and a g e n e r a l two-body i n t e r a c t i o n . The f o r m a l i s m i s a p p l i e d to s p h e r i c a l n u c l e i and t h e r e s u l t s a r e compared w i t h t h o s e o b t a i n e d i n p u re p a i r i n g f o r c e case and t h e H a r t r e e - P o c k c a s e .

♦ S up p o r te d by t h e N a t i o n a l R e s e a rc h C o u n c i l .

9: 15ζΡΰ The Enerev Levels in 96Tc via (a.n) Reaction.

H. MACH, M. JOHNS, J. THOMPSON, McMaster Univ.— The energy levels of 3°Tc have been investigated using the g3Nb(a,ny)9&Tc reaction. The following experiments have been performed: singles, excitation function, γ-γ coin­cidence, η-γ coincidence, angular distribution and internal conversion measurements. States in 96Tc have been identified at the following energies: 34.4, 49.3,177.1, 319.0, 506.1, 565.0, 574.7, 751.3, 814.9, 927.0,946.1, 1061.7,1446.9, 1702.2, 1860.7, 1922.4, 2147.0, 2212.8, 2317.7, 2395.9, 2599.5 and 2642.9 keV. The spin and parity assignments as well as the interpreta­tion of the states are under active consideration.

l8

9 = 20CF3 104

Decay o f l u U n . * H. HUANG, B .P .

PATHAK and J . K . P . LEE , M c G i l l U n i v --The l e v e l s t r u c t u r e o f 104cd has been s t u d i e d f ro m t h e decay o f 1 0 4 χn u s i n g s- and γ- s p e c t r o s c o p i c m e th od s . The r a d i o a c t i v e s o u rc e s we re p rodu ced v i a ( p , 3 n ) r e a c t i o n on e n r i c h e d °Cd

t a r g e t s . γ-γ c o in c i d e n c e m e asu rem en ts u s i n g two G e ( L i ) d e t e c t o r s w e re p e r fo rm e d and a d ecay scheme was o b t a i n e d . The t im e d e c a y in g

c h a r a c t e r i s t i c s o f t h e γ - r a y s i n d i c a t e s t h a t t h e r e a r e two p o s s i b l e d e c a y in g i s o m e rs w i t h

h a l f - l i v e s o f 1 .6 t 0 .2 and 2 . 0 ± 0 .2 m in H o w e ve r , s i n c e t h e s e h a l f - l i v e s a r e s i m i l a r , and i t i s l i k e l y t h a t t h e i r s p in s a re n o t to o d i f f e r e n t f r o m each o t h e r , c o n s e q u e n t l y , no

s e p a r a t e d ecay schemes w e re d educed . The β- e n d - p o in t e n e r g i e s f o r v a r i o u s b ra n c h e s

f e e d i n g d i f f e r e n t l e v e l s i n 1 04cd w e re o b t a i n e d u s i n g β-γ c o in c i d e n c e m e th o d s , y i e l d i n g a QEC v a l u e o f 7 .0 ± 0 .2 MeV f o r

one o f t h e ^ ^ I n i s o m e r s . R e s u l t s w i l l be d is c u s s e d i n c o n j u n c t i o n w i t h l e v e l s t r u c t u r e s

o f o t h e r e v e n- e ve n Cd n u c l e i

‘ R e s e a rc h s u p p o r t e d by t h e NRC.

CF7 High Spin States in 11,9Tb. N.C. SINGHAL,M.W. JOHNS and J. THOMPSON, McMaster Unlv.— In-beamγ-ray studies have been made for neutron deficient Î^Tb using the reactions **2Nd ( * 0B, 3n) and *1+Í4Sm(Li,2n) at 54 MeV and 32 MeV respectively. Excitation func­tions, angular distributions and prompt γ-γ coincidence spectra were obtained. A decoupled band with AI=2 based on the 11/2” isomeric state in ll+0Tb is strongly excited and has the following members; 786.6(15/2“), 1346.2(19/2“), 1636.9(23/2“), 2267.6(27/2”) and 2628(31/2“) keV. High spin positive parity states are also strongly excited and the maximum spin observed is 45/2+ . The energies (in keV) and spins of these states are as follows; 1093.3(15/2), 1832.0(19/2), 2314.7(23/2) 2482.9(27/2), 2777.2(29/2), 3106.6(31/2), 3492.2(33/2), 4172(31/2), 4428.2(35/2), 4639.0(37/2), 4885.0(41/2) and 5110.0(45/2). A level scheme based on these mea­surements and an interpretation of the excited states will be presented.

10:1*5

9 ^ 5CFU Energy L e v e ls o f l 2 l Sb arid l28Sb E x c ite d from

the (η,η*γ) Reactions. H.R. HOOPER, P.W. GREEN,H.E. SIEFKEN,T G.C. NEILSON, and W.J. MCDONALD,Nuclear Research Centre, University of Alberta—A study of energy levels excited in the 1 * * 3Sb(n,n 'γ) reactions is presently being carried out. The energy level structures of these isotopes, up to E - 2.2 MeV, is investigated and compared with previous results. As well, γ-ray angular distributions are measured, and spins and γ-ray multipole mixing ratios deduced. Defin­ite spin assignments have been made for states at 947 keV (9/2), 1025 keV (7/2), and 1145 keV (9/2) in 12*Sb, and at 1030 kev (9/2) in 123Sb. These experimental results are compared with seme recent model calcula­tions.

^Permanent Address: Department of Physics, GreenvilleCollege, Greenville, Illinois.*Work supported in part by the National ResearchCouncil of Canada.

10:15S t r u c t u r e o f f r o m t h e Decay o f

1 3 8 Pm.* j DESLAURIERS and S .K MARK, M c G i l l

U n iv . - - T h e s t r u c t u r e o f 1 38 n d has been . i n v e s t i g a t e d t h r o u g h t h e b e ta d ecay o f °Pm whose h a l f - l i f e i s m easu red t o be 3 .2 4 ± 0 .0 3 m in . A l e v e l scheme c o m p r i s i n g 23 s t a t e s i s p roposed The t o t a l d ecay e n e rg y i s measu red and compared w i t h t h e p r e d i c t i o n s o f mass f o r m u la e and d is c u s s e d i n te rm s o f th e s y s t e m a t i c s o f t h e o t h e r e ven A N=77 i s o t o n e s . S p in and p a r i t y a s s ig n m e n t s a r e deduced f rom d ecay p r o p e r t i e s . The s t r u c t u r e o f 1 3 8 n d i s compared w i t h t h a t o f t h e o t h e r even A N=78 i s o t o n e s ; t h e s e n u c l e i a r e d e s c r i b e d in the t w o - q u a s ip a r t i e l e BCS f o r m a l i s m u s in g T a b a k in i n t e r a c t i o n s .

^ R e s e a rc h s u p p o r t e d by t h e N a t i o n a l R e s ea rc h C o u n c i l .

10:30CF6 Study of Neutron Deficient Tb Nu c lei.

M.W. JOHNS^N.C. SINGHAL and J. THOMPSON, McMaster Univ.— Neutron deficient terbium isotopes (I4/Tb, 1U0Tb, 14^Tb) have been studied using &Li, 'Li, 1CB and n B induced reactions. Excitation functions, angular distributions and γ-γ coincidence measurements have been made and a number of "mini-decay" schemes have been established in u7Tb, ^40Tb and ^u^Gd, 0Gd. The problem of identifying these with specific nuclei will be discussed.

11:00CFÔ The Level Structure of ^00Er. J. D. PANAR and

D. G. BURKE, McMaster Univ.— Single particle transfer reactions leading to states in l00Er up to 3.6 MeV in excitation energy have been studied. Beams of 24 MeV 3He, 27 MeV α-particles and 15 MeV deuterons from the McMaster University FN Tandem Accelerator were used for the (3He,d) and (a,t) proton transfer reactions, and the (d,t) and (3He,a) neutron transfer reactions.Several spin assignments have been made, based on observed peak intensities and on transferred 2,-values. The Z-values were obtained from (3He,d) and (d,t) angu­lar distributions, and from the (3He ,d)/(a,t) and (3He,a)/(d,t) cross section ratios. Due to improved resolution and the availability of angular distribu­tions it has been possible to correct several erroneous assignments made in an earlier proton transfer study!'* . In the (d,t) reaction, several levels populated by Z=0 transfers are observed. The properties of these states can be explained by considering AN=2 and Coriolis mix­ing of the 7/2“[523] 0 l/2+ [400] configuration with other states. Evidence for proton-neutron mixing is found in that several levels are populated significant­ly in both the proton- and neutron-transfer reactions.1) Katori, K. et al., Phys. Rev. C Vol. 9, (/I 360 (1974)

xj. ; xpCF9 Resonances at 9 MeV in ^00Pb. N.K. SHERMAN,

C.K. ROSS, and K.H. LOKAN, National Research Council, Ottawa, and H.M. FERDINANDE, Rijksuniversiteit, Ghent, Belgium — The differential cross section for the íOöpb(γ ,n)207Pb reaction has been measured at 8 angles for photon energies from 7.9 to 10.2 MeV. The angular distributions of the resonances up to 8.3 MeV are con­sistent with recent measurements^ of spin and parity. The 9.034 MeV state2 has a nearly isotropic distribu­tion consistent with J7* - 1 . A weaker resonance at 8.95 MeV has a distribution about the beam direction which peaks at about 97°, indicative of 1 . The 9.08 MeV resonance is strongly peaked and nearly symmetric about 90°, consistent with pure d-wave emission from a 1“ state, or with an Ml assignment. This could be the state identified as a monopole excitation in one (P»P*) experiment.!r .j . Holt and H.E. Jackson, Phys. Rev. Lett. 36, 244 (1976).

2N.K. Sherman, H.M. Ferdinande, K.H. Lokan, and C.K. Ross, Phys. Rev. Lett. 35, 1215 (1975).

19

Chairman: . uglas

TUESDAY, JUNE 21, 1977 SUPERCONDUCTIVITY AND POSITRONS IN SOLIDSROOM 127

9:00CGI Low frequency a.c. losses In the Current- Induced Intermediate State In Type-I Superconductors.* B.K. MUKHERJEE, H.D. WIEDERICK, and D.C. BAIRD, R.M.C. Kingston.- The d.c. current-induced intermediate state in Type-I superconductors shows low frequency a.c. losses (resistance) much greater than attributable to its d.c. resistance. We find that this enhancement in the a.c. resistance is a function of the intermediate state structure, being greatest at the onset of the intermediate state. The enhancement is also a function of the a.c. frequency and disappears at high frequencies Our observations can be understood by attributing the additional a.c. resistance to the eddy-current losses which occur during the motion of interphase boundaries in the superconductor.

♦Work supported by Defence Research Board of Canada Grant No. 7345-3610-320.

9:15CG2 Resistivity Evidence for the Correlation Between Superconductivity and Optical Phonons in Pd-H. j. c. H. CHluT" Brandon Univ.- From electrical resistivity measurements on Pd-H samples we have separated out the optical and acoustic phonon contributions. The onset of optical resistivity coincides with the occurrence of superconductivity, supporting the recent evidence that optical phonons play the major role in the formation of superconductivity in Pd-H system.

9:30CG3 Crystalline Electric Field Effects in Super­

Conducting Bi-Pr Alloys , C.S.LIM and J.D.LESLIE,Physics Dept., Univ. of Waterloo - We have carried out experiments on Al-Al oxide-Bi^_xPrv tunnel junctions where the Bi-Pr superconducting alloys were prepared as thin films quench-condensed onto substrates at helium temperature in an evaporator-cryostat. The introduction of Pr into Bi does depress its transition temperature, however the depression is much less than predicted by the theory of Abrikosov-Gorkov. The transition temper­atures are 5.90, 4.45, and 2.25°K for 0.3, 7.0, and 30 atomic % Bi Respectively. The tunneling conductances of our junctions exhibit structure which can be^explained in terms of the calculation of Holzer et al ,provided we assume that the crystalline electric field split energy levels in our Bi-Pr films are the same as those determined by Birgeneau et al for bulk BiPr. We believe that our experimental results are the first confirmation of the theoretical predictions of Holzer et al.Finally, our results indicate that the short-range order in the Bi-Pr alloy system is very stable,since quench-condensa- tion can not alter it significantly.

(1) P.Holzer,J.Keller, and P.Fulde,J.Low Temp.Phys.14,247 (1974)

9:^5CG4 A New Technique for Electron Tunnel Junction

Fabrication , V. KEITH and J.D.LESLIE, Physics Dept., Univ. of Waterloo - This new technique involves ion etch­ing a hole through an insulating layer on the surface of a superconducting sample until Auger spectroscopy indi­cates that a clean surface of the superconductor has been attained. Then thermal or plasma oxidation of the clean surface at the bottom of the hole produces the tunneling barrier. Finally, a metal evaporation over the hole completes the tunnel junction. Tunneling results ob­tained with Ta-Ta 0 -Pb or Ag and Nb-Nb 0 -Pb or Au tun­nel junctions so prepared on bulk and foi¥ samples are presented. Structure in the current-voltage characteris­tics due to the proximity effect is explained quantita­tively using McMillan's theory. The explanation is sub­stantiated through our observation that a reduction of the proximity layer thickness due to a lower ion etching energy is associated with a reduction of the excess cur­rent above the voltage corresponding to the sum of the energy gaps. It is proposed that excess current below this voltage is due to tunneling through normal regions of Nb and Ta in parallel with tunneling through the superconducting regions.

10:00Maintenance of the Canadian Unit of EMF With

the Josephson Effect. G. H. WOOD, National Research Council. Ottawa--A suitably biased superconducting Josephson junction serves as a very precise frequency- to-voltage transducer in which the proportionality fac­tor is the ratio of fundamental constants 2e/h. The exploitation of this phenomenon to maintain the Canadian unit of emf (the volt, Vjjrç) in terms of these constants, rather than the electrochemical potential of saturated Weston standard cells, will be described. Recent results indicate the experimental uncertainty is close to the immediate objective of 1 part in 1θ7.

10:30CG6D ete rm ina tion o f Small Void Sizes by Pos itron

L ife t im e s * . R. GRYNSZPANT, B .T.A . MCKEE, and A .T .

STEWART, Queen's U n iv . -- The trapp ing o f p os itro ns a t vo ids p rovides a powerful technique fo r the study of the nuc léa tio n and e a r ly stages o f growth o f vo ids which are s t i l l too sm all to be reso lved by conven­t io n a l e le c tro n microscopy. We p resent a simple c a lc u la t io n , based on a surface trap p ing model1 ,

which re la te s the vo id rad iu s to the trapped p os itro n l i f e t im e . Measurements o f p o s itro n trapp ing in molybdenum ir ra d ia te d a t 100°C to fa s t neutron fluences o f 6.5 x 1019cm“2 and 2 x 1020crrr2 revea l

the presence o f ve ry sm all vacancy c lu s te rs . Based on the model c a lc u la t io n , the mean vo id d iam eter in these samples is estim ated to be about 6A, equ iva­le n t to a c lu s te r o f about 8 vacancies. The v a l id i t y o f t h is convenient model w i l l be discussed.♦Supported by N.R.C.'Seconded from C .N .R.S. - Centre d'Etudes de Chimie

M é ta llu rg iq u e , V i t r y , France.^ .H . Hodges and M.J. S to t t , S o l. S t. Comnum. ] 2 ,

1153 (1973). '

20

CG7Recovery o f Deformed Copper stud ied by Pos itron

L i f e tlm e* . B .T.A. MCKEE, S. SAIMOTO, and A .T7 STEWART, Queen's U n iv . -- Extensive stud ies by e le c t r ic a l r e s i s t i v i t y and flow s tress measurements o f the te n s ile deformation and subsequent recovery during isochronal

annealing of hjgh p u r i ty copper c ry s ta ls have re c e n tly been repo rted . We have performed p os itro n l if e t im e measurements on some corresponding Cu samples, de­formed in tension in the [100] o r ie n ta t io n a t room temperature. P a r t ic u la r a t te n t io n has been g iven to

the recovery below 300°C, because the r e s i s t i v i t y measurements have ind ica ted the annealing in th is temperature range o f a defect type which does not a f fe c t the flow s tre ss . The pos itron technique is se n s it iv e to th is defect species annealing below 300°C, although a unique assignment of the species is not poss ib le . The present data ind ica te th a t vacancy c lu s te rs la rg e r than a few atoms are not in vo lved , and are cons is ten t w ith the hypothesis th a t these defects may be d is lo c a tio n loops.*Supported by NRC.^ . S . B as in s k i, M. Sahoo, and S. Saimoto, to be pub- 1ished in A c ta . M et.

10:1)5

11:00CG8 Positron Trapping at Dislocations in Metals.

B. BERGERSEN, UBC and T. McMULLEN, Queen's U.— The trapping rate of positrons at a model of a dislocation in a metal, and the temperature dependence of this rate, are calculated. The dislocation is represented by a cylindrical square well. Two different trapping processes, trapping mediated by electron-hole pair ex­citation and trapping mediated by phonon creation, are considered. The wavefunétions and binding energies for positrons trapped at dislocations are not very well known at present. For the range of trapped state energies used here the particle-hole mechanism is found to be the dominant one. It gives a temperature indep­endent trapping rate. However, the phonon mediated rate increases with temperature, and for low binding energies provides a significant correction to the particle-hole rate. The possible significance of classical diffusion of positrons is discussed.

CG9 Parameterization of Doppler-Broadened Annihilat­ion Energy Spectra in Metals. I. K. MacKENZIE, P. J. SCHULTZ, T. E. JACKMAN, J. FABIAN and J. R. MacDONALD, Univ. of Guelph.Indium and nickel are used as test cases to demonstrate the accuracy attainable in deducing the fraction of trapped positrons from Doppler-broadened annihilation energy spectra. The data are analyzed on a channel-by­channel basis, by comparison of second moments and by superposition of spectra. These standard techniques are then compared with less conventional, but familiar, analyses using the S-parameter and its variations. New parameters are introduced which use difference curves to produce channel-by-channel weighting factors to improve trapping sensitivity. The benefit of these new parameters will be demonstrated in linear annealing studies on Cu and brass.

1 1 : 1 5

11:30

CG10 Tests of the Existence of Positronium in Polymeric Solids T. E. JACKMAN, J. R. STEVENS and I. K. MacKENZIE, Univ. of Guelph.The observation that the narrow component in the momentum spectrum in solid hydrocarbons has an anomalously low intensity compared to the long-lived component in the time spectrum has raised doubts about the existence of a posit­ronium state in these materials.‘ We have investigated the possibility, first discussed by Goldanski2, that the anomaly arises from the swelling of positronium in some polymers. Experimental evidence is presented from 3γ/2γ ratios, magnetic quenching effects on time spectra and dual-parameter age-momentum correlations.

1 De Blonde, G. et al. Can. J. Phys. 50, 1619 (1972).

2 Goldanskii, V. I., Positron Annihilation, Academic Press, New York, 1967.

21

TUESDAY, JUNE 21, 1977 NUCLEAR PHYSICS 1ROOM 130Chairman: J.A. Kuehner

13:30DAI Symmetries in Nuclear Beta Decay

F.P. CALAPRICE, P/UnceXon UniveAAZty

14:15DA2 Hartree-Fock Approach To Exotic Nuclei

J.M. p e a r s o n, U y U v e/u lte d e M on trea l

15:00DA3 Time Evolution Studies of Heavy Ion Induced Fission Using Crystal Blocking Techniques

J .s . FORSTER, CkaZk flivCA Nucl&Vi La.boncLtoru.&t>

15:45DA4 Nuclear Structure Studies Using Pion Probes

R.R . JOHNSON, UviiveAA-cty Τ&λ ΛλλΗ Columbia and TR7UMF

TUESDAY, JUNE 21, 1977 CONDENSED MATTER SYMPOSIUMROOM 103

Chairman: W .J.L. Buyers

13:30DB1 Elementary Excitations in Normal Liquid JHe

F.c . k h a n n a, CkaZk HivCA Slucle.a,>i Labo>icLtonJ.eA

Recently, using inelastic neutron scattering techniques, the dynamic structure factor, S{q,tu), for liquid ^He has been determined at two temperatures (T=15 mK and 0.63 K) for 8<_Q<_25 nm" 1 . A zero- sound mode at fiú = 1 meV and a paramagnon mode at much smaller Αω were observed in the low tempera­ture experiment. In this talk an RPA calculation^ aimed at explaining the excitation spectrum of liquid ^He, based on the Landau theory of Fermi liquids, is described. A phenomenological exten­sion of the Landau quasi-particle interaction to finite T by a temperature-dependent effective mass provides a reasonable description of the experiments at high temperature. At low T the position of the zero-sound mode and the position and Landau damping of the paramagnon mode are predicted re­markably well. The dependence of S(Q,w) on Q and T is reproduced. An attempt is made to justify the extension of the Landau theory to finite Q, ω and T within a microscopic theory. The quasi­particle interaction is written in terms of a ^-matrix (including effects of the Pauli principle) obtained from a Lennard-Jones type two particle potential. A realistic calculation for the excita­tion spectrum and the spreading width of the zero-sound mode is described.

1 . H .R. G lg d e & F .C . K hanna, P h y s . R ev . L e t t . 3 7 (1 9 7 6 )1 6 9 2 an d r e f e r e n c e s q u o t e d therein.

14:15DB2 Dissipation in the Transport of the Superfluid Helium Film

r .f . h a rr i s -LOWE, PoyaZ A\ZtUaAij College

The transport properties of the superfluid helium film will be reviewed, along with various theories which have been proposed in attempts to explain the breakdown of pure superfluid flow and the appearance and rapid increase of dissipation at super-critical velocities. Some of the difficulties in explaining the various observations will be discussed, in particular the difficulties which arise when one tries to explain the existence of metastable flow states within the framework of earlier theories. A new mechanism is pro­posed which accounts for the appearance of dissipation in terms of the continuous generation of pinned vortex lines, and which explains many of the puzzling observations concerning film transport as being due to changes in the number of pinned lines and/or the location of the pinning points. Quantitatively, this theory pre­dicts that at superfluid velocities v which just exceed the critical velocity v for the appearance of dissipation, the rate of dissipation SQ is given by Q = AN(vg - vc)3/2 where N is the number of pinned vortex lines and A is a constant determined by the vortex line parameters in the film. The value of 3/2 for the exponent represents the first precise prediction by any theory of a parameter associated with dissipation in the helium film, and recent experiments which will be discussed appear to confirm this prediction.

22

DB3 Electric Quadrupole Interactions In Metals: Systematic TrendsE.J. ANSALDO, UniveJUity of, Saikntchem n

1 5 :0 0

In recent years the quadrupole interactions acting on foreign nuclei in metallic crystals have been measured for a large variety of impurity-host combinations. The experimental techniques to be discussed are a) implantation of radioactive atoms into single crystals by means of isotope separators and nuclear reactions, and b) measurement of the magnitude and sign of the interaction through the precession of the angular distribution of the nuclear radiations. The experimental data will be shown to illustrate the two main (unexpected) systematic trends found: I) The electric field gradients due to lattice and conduction electrons appear to be directly proportional to each other, the controlling parameter for the total field gradient being the Sternheimer antishielding factor for the impurity atom, and II) the temperature dependence of the interaction follows a T^/2 iaw for most cases. Current attempts at explaining such behaviour will be discussed. As a by-product of such studies, information on lattice location and radiation damage is often ob­tained. This will also be discussed briefly.

15:45DB4 Brillouin Scattering in Rare Gas Crystals

B.P. STOICHEFF, U n ivem ity of, Toronto

Brillouin spectroscopy has been used to determine elastic constants of single crystals of Ne, Ar, Kr, and Xe, near their triple points. The theory will be reviewed briefly, and the experimental technique used to measure elastic and photoelastic constants will be described. Values of these contants will be discussed and compared with values obtained by other experimental methods and by recent theories.

TUESDAY, JUNE 21, 1977 HEALTH PHYSICSROOM 126Chairman: J.C .F . MacDonald

13:30DC1 The Role o f the AECB in A cce le ra to r Safe ty D.H.

SYKES, Atomic Energy Contro l Board, O tt. -- The Atomic

Energy Contro l Board licenses f a c i l i t i e s which inco rpo r­ate equipment defined in the Atomic Energy Contro l Regulations as p a r t ic le acce le ra to rs . Advice regard ing the sa fe ty aspects o f the design, manufacture and supply of acce le ra to rs and the in s t a l la t io n , opera tion and use o f ac ce le ra to r f a c i l i t i e s is provided by Board s ta f f and an A cce le ra to r S a fe ty Adv iso ry Committee. Recommenda­tions may be made regard ing the g u id e lin e s and standards which are app licab le to c e rta in classes o f acce le ra to rs o r a c ce le ra to r f a c i l i t i e s as w e ll as to sp e c if ic in s t a l­la t io n s . One c lass o f ac ce le ra to r and f a c i l i t y which is of p a r t ic u la r in te re s t is th a t which is used fo r medical treatm ent purposes.

13:45DC2 Standards and Regulations on Radiation Devices in the U.S.A.

M.S. LITTLE, Btoieau o(J Rad io log ica l Health, R o c kv ille , Maryland

Radiation protection programs in the U.S. evolved around voluntary, national, and international product standards and exposure guidelines. Mandatory standards are becoming increasingly evident at both the State and Federal levels. This paper will discuss the coordinated efforts of State and Federal agencies in the development and implementation of voluntary and regulatory standards and related regulations for products which emit or influence the emission of ionizing and nonionizing radiation.

DC3 Federal Contro l o f R ad ia tion E m itt in a Devine·;

M.H. REPa l h u l i, W.M. ZUK and S.K. GHOSH, X-Rays and Radia tion Devices D iv is io n , R ad ia tion P ro tec tion Bureau, Health and W elfa re Canada, Ottawa.Under the Rad ia tion E m ittin g Devices (RED) Act, the Federal Government regu la tes design, construc tion and

performance o f new devices to be so ld o r imported in to Canada. The Food and Drugs Act medical devices re g u la ­tions can a lso be used to d ra f t performance standards fo r medical ra d ia tio n devices. Use o f these devices in e s ta ­blishments coming under Federal ju r is d ic t io n are c o n tro l­led under the Canada Labour Code and Treasury Board Standards. The Rad ia tion P ro tec tio n Bureau is respons i­b le fo r determ ining p o te n tia l hazards from ra d ia tio n devices, proposing re g u la to ry ac tio n , determ in ing ra d ia ­tio n b io e ffe c ts , fo rm u la ting hea lth c r i t e r ia , and deve lo­ping ra d ia tio n measurement techniques. Contro l o f ra d ia ­t io n devices has been d iv id ed in to two major areas, those em itt in g io n iz in g and non- ion iz ing ra d ia tio n s . The pro­cedures and philosophy used in developing re g u la tio n s , the s ta tus o f cu rren t re g u la t io n s . Federal in te ra c t io n w ith o th e r standards s e t t in g o rgan iza tio ns and p ro fe ss io ­nal a ssoc ia tio n s , and the ro le o f the Rad ia tion P ro tec­tio n Bureau in developing hea lth c r i t e r ia w i l l be d iscus­sed .

l i t : 30

15:15Health Physics Regulations In Nova Scotia.

J. E. ALDRICH, Victoria General Hospital, Halifax.The Province of Nova Scotia adheres to the federal acts covering radiation protection and control, i.e. the Radiation Emitting Devices Act, the Atomic Energy Control Act, and the regulations thereunder. At the 1960 Session of the Legislature there was passed an amendment to the Public Health Act entitled Radiation Hazard Control covering the registration and inspec­tion of radiation producing devices. As yet only the registration of such devices has been implemented.The Department of Public Health intends to draw up a set of regulations for the use of radiation in the near future. The Medical Radiological Technicians Act regulates the practice of medical radiological tech­nology. Under the Workmen’s Compensation Act every employer must keep records of the radiation exposure of workers.

15:30DC5 Manitoba X-Ray Safety Regulations. A. F.

HOLLOWAY and E. M. C. CAMPBELL, The Manitoba Cancer Treatment and Research Foundation.— Manitoba Regulation 39773 under The Public Health Act is administered under the terms of a contract with the Department of Mines Resources and Environmental Management. The purpose of the Regulation is to ensure that patients, staff, and the general public are not subjected to unnecessary radiation. The Regulation requires the registration of all devices whose principal purpose is the production of x-rays, together with such ancillary apparatus as may be necessary for

th is purpose. The R egu lation a ls o provid es for in sp e c tio n and approval of x -ray i n s t a l la t i o n s . To date 855 u n its have been r e g is te r e d and 714 i n s t a l l ­a t io n s in sp e c te d . Approval has been granted to 672 i n s t a l la t i o n s , w ith h eld from 80 and su b seq u en tly granted to 59 . N in ety -th r ee u n its have not been in sp e c te d , 64 o f them being out o f s e r v ic e and 29 not y e t in sp e c te d . The R egu lation would be improved by the in c lu s io n of a requirem ent for x -ray companies to inform the reg u la to ry a u th o r ity when s u b s ta n t ia l a l t e r a t io n s are made to th e equipment or when new or used equipment i s so ld .

15 = 5DC^ Rad ia tion Safe ty of Baggage X-ray Systems at

Canadian Ai rp o r ts . E. RABIN and W. M. ZUK, Radi a tio n P ro tec tion Bureau, Health and W elfare Canada.--The in c reas ing incidence of a i r c r a f t h ija c k ing s in the la te 1960's and e a r ly 1970's forced c i v i l a v ia t io n a u th o r i­t ie s to in troduce a irp o r t s e c u r ity measures designed to p ro tec t aga inst such h ija c k in g s . An im portant compon­ent o f these measures a t a l l major Canadian a irp o rts was the in s ta l la t io n and use o f X-ray equipment fo r detec ting weapons in carry-on baggage. In view o f the p o p u la r ity o f a i r t ra v e l th is measure gave r is e to the p o s s ib i l i t y o f unnecessary X-ray exposure to a la rge f ra c t io n of the Canadian popu la tion . To ensure th a t the X-ray equipment did not p resent a hazard to operators o r the t r a v e l l in g p ub lic , the Rad ia tion P ro tec tion Bureau, a t the request o f the federa l M in is t ry o f T ranspo rt, developed and implemented s t r i n ­gent sa fe ty standards o f design, construc tion and pe r­formance o f such equipment. These standards, re cen tly promulgated as Regulations under the Rad ia tion E m ittin g Devices Act, w i l l be described and th e ir im p lic a tio n in terms o f ra d ia tio n exposure to operators and the t r a v e l l in g pub lic w i l l be discussed.

1 6 : 0 0DC7 Survey o f V e te r in a ry X-ray F a c i l i t ie s in the

Ottawa Area. W. M. ZUK, A. TOD, L. SZEGEDI and J. GORDON, Rad ia tion P ro tec tion Bureau, Health and W elfare Canada.--A survey o f th ir te e n v e te r in a ry c lin ic s in the Ottawa area was conducted to assess the s ta te of ra d ia tio n sa fe ty o f X-ray equipment and f a c i l i t ie s used by v e te r in a r ia n s . The m a jo rity of the X-ray un its were found to be in excess o f 10 years o ld , were im p roperly in s ta l le d o r used, and contained defects, such as inaccurate tim ers and excessive X-ray leakage from the tube head. The re s u lts o f the survey w i l l be presented and the steps necessary to reduce the hazards to v e te r in a ry personnel w i l l be discussed.

2U

TUESDAY, JUNE 21, 1977ROOM 128Chairman: J. Teichmann

PLASMA PHYSICS I I

13:30DPI Interaction of C0?-laser light with a Z-pinch

plasma.* J. MEYER, G. ALBRECHT and H. HOUTMAN, Univ. of British Columbia.-- The interaction of a high power CO2 laser beam with a plasma produced in a fast Z-pinch is studied experimentally. The laser beam of 200MW power is focussed along the axis of the discharge during the pinch phase. At this time the plasma has reached a density of 3-4 x 1018 cm-' and a temperature exceeding 20eV. The plasma parameters and stimulated fluctuations are investigated by analyzing the spectrum of foreward and backward scattered ruby laser light.

*Supported by the N.R.C.

13:1*5DD2 Claquage à 1*Interface entre la cible et le

plasma laser. MICHEL G. DROUET, direction Sciences de base, 1REQ, Varennes, Québec, Canada JÓL 2P0 — Nous examinons l'évolution temporelle du courant électrique émis par une cible de cuivre irradiée par une impulsion laser CO2 (Valcartier 1.7 ns, 2.5 GW, 1.3 mrad) dans une atmosphere d'argon à une pression variant entre 10"** et 1 torr. Le courant croît jusqu'à une valeur critique pour décroître ensuite de façon exponentielle. Les résultats sont interprétés comme indiquant que la source de courant dure jusqu'à 150 ns - c'est-à-dire beaucoup plus longtemps que l'impulsion laser de 1.7 ns - et qu'un claquage se produit à l'interface plasma- cible. Le claquage permet au courant de court-circuiter la cible et de se refermer au travers du plasma. Le claquage se produit avec un délai, par rapport a l'im­pulsion laser, qui croît avec la pression du gaz. Cette observation est attribuée au fait qu'à basse pression, la topologie du courant occupe un plus grand volume et que la vitesse du plasma laser est également plus gran­de. A la suite du claquage, la cible est blindée con­tre le champ magnétique intense, créé dans le plasma laser.

lh:00Photoionisation de l'hélium et de l'azote par

des rayons-X mous produits dans l'interaction d'une im­pulsion laser CO? sur une cible de cuivre. MICHEL G. DROUET, direction Sciences de base, IREQ, Varennes, Québec, Canada JÓL 2P0 — La source de rayonnement est un plasma produit par l'interaction d'une impulsion la­ser CO2 (Valcartier 1.7 ns, 2.5 GW, 1.3 mrad) focalisé sur une cible de cuivre épaisse dans une atmosphère d'hélium ou d'azote. Un collecteur de charge est uti­lisé pour la mesure de la dépendance de l'émission pho­to-électrique sur la pression du gaz. L'atténuation du rayonnement par le gaz correspond à une section effica­ce de photoionisation de 0.4 Mbarn dans l'hélium et de0.9 Mbarn dans l'azote. Les résultats sont discutés en tenant compte que la valeur de la section efficace dé­terminée ici pour l'hélium correspond1 à une longueur d'onde de 120 R ± 10 X alors que la valeur tabulée pour l'azote2 à 150 S est approximativement 3 ± 1.5 Mbarn; nous prendrons également en considération le fait que le cuivre émet à 110.6 A (transition M^).

1 Lowry, J.F. et al., Phys. Rev. 137, A 1054 (1965).

2 Curtis, J.P., Phys. Rev. 94, 908 (1954).

lU : X5DD4 Parametric In s t a b i l i t ie s in Inhomogeneous

Plasmas. A.K.H. NG, M.R. CERVENAN and A.A. OFFENBERGER. bept. of E le c t r ic a l En ingeerinn, Univ. o f A lb e rta -

A hydrogen gas ta rg e t has been ir ra d ia te d w ith C07 l^ s e r ra d ia tio n a t focussed in te n s it ie s up to lO '^w a tts^cm .

Depending upon the gas ta rg e t pressure, plasmas of various d en s itie s were produced. Thus, by systemmat- ic a l ly inc reas ing the ta rg e t pressure, one may study the f u l l spectrum o f param etric processes from stim u la ted sca tte ring in s t a b i l i t ie s in underdense plasmas, to two- plasmon decay a t 1 /4 - c r it ic a l dens ity and to param etric decay and ősei 1lating-two-stream in s t a b i l i t ie s a t c r it ic a l- d e n s ity . Ruby la s e r in te rfe ro m e try and Thomson sc a tte rin g techniques were employed to provide d e ta ile d space and time reso lved in fo rm ation on induced dens ity f lu c tu a t io n s and in s t a b i l i t y growth-

ra te s . Results o f the various measurements w i l l be presented.

14:30005 Pressure Dependence of Stimulated Brillouin___

Scattering from a Hydrogen Gas Target. M. R. CERVENAN and A. A. OFFENBERGER, Department of Electrical Engin­eering, Univ. of Alberta.In an earlier work (1) we have reported stimulated Brillouim Scattering (SBS) from underdense hydrogen plasma (ne -v .2-1.3x1018cm"3) for the intensity of the focussed 10.6μ radiation in the range ,5-l.OxlO11 Wcm"2. To increase this intensity a shorter focal length system was used. The temporal characteristics of the SBS pulses agree qualitatively with that expect­ed for the shorter plasma columns corresponding to the new system. Some evidence indicating possibility of saturation in the process of SBS has been observed. Investigation of the pressure dependence of the SBS was carried out up to critical density. Substantial increase of the peak intensity and more than an order of magnitude increase of the back scattered energy of the SBS was observed.

1A.A. Offenberger, M.R. Cervenan, A.M. Yam and A.W. Pasternak, J. Appl. Phys. 47, 1451 (1976).

14:45

DD6 CO2 Laser Irradiation of Solid Targets in HighMagnetic Fields.* W. HALVERSON, N.G. LOTER. W.W. MA, C.V. KARMENDY and J.H. WATTS, M.l.T. Francis Bitter Nat'l Magnet Lab.t and R.W. MORRISON, Carleton University.-- The mass loss from carbon targets damaged by gain-switched 225 J COa laser pulses is reduced more than 20-fold by the application of a 100 kG field. Soft X-Ray diagnostics indicate that the electron temperature of the plasma near the target is about 300 eV during the spike of the laser pulse and has a rapid temporal and spatial decay at all magnetic field values. At fields greater than 30 kG a strongly radiating plasma is partially confined for periods up to 300 nsec in a region extending several cm. from the target. The time of formation of this plasma, whose elec­tron temperature is about 100 eV, is reduced with increasing magnetic field.•Supported in part by USAFOSR. fSupported by the National Science Foundation.

15:00DD7 Interactions a Quatre Ondes et ses Applica­

tions*. D.L. NGUYEN, K.J. PARBHAKAR et T.W. JOHNSTON, INRS-Energie, Univ. du Quebec. — Les interactions à quatre ondes dans un plasma chaud à deux fluides sont considérées et les matrices d'interaction sont déter­minées. On montre que les interactions à quatre ondes sont constituées en général de trois processus élémen­taires dont chacun implique une onde virtuelle. Le taux de croissance du processus t^ + % -*■ + s, dontl'application pratique correspondrait à la génération des harmoniques 2tü et 3ω /2 (ω étant la fréquence de l'onde incidente) est obtenu.

15:145DD10 Plasma Param etric A m p lif ie r fo r In fra re d Laser

R ad ia tio n . R.D. MILROY, C.E. CAPJACK, and C.R. JAMES, Dept, o f E lec. Enq., U. o f A lb e rta - A pp lica tio n s of the non linea r m ixing of two in tense la s e r beams in a plasma are examined. I t is found th a t i f a 10.6 um C0? la s e r were used to produce a pump beam o f in te n s ity

11 210 W/cm an e xpe rim en ta lly re a liz a b le device could be made to am p lify beams in the 11 -16um wavelength range.

Also examined are the im p lic a tio ns of using th is process to tu rn a la s e r beam around in s id e a long so lenoid

re ac to r.

*Work supported by NRC

15 = 15

DDÔ Evolution temporelle des interactions à quatre, ondes*. D.L. NGUYEN, K.J. PARBHAKAR et T . wT JOHNSTON7 ” INRS-Energie, Université du Québec. — L'étude du sys­tème d'équation des modes couplés décrivant l'évolu­tion temporelle des interactions à quatre ondes est présentées. En général, les ondes évoluent périodi­quement. Toutefois, lorsque deux des ondes ont la même densité d'action, le comportement du système change complètement et les ondes évoluent de façon apériodique. Les processus de diffusion mutuelle et d'autre diffusion, qui introduisent une modulation de phase des ondes, ont un effet d'interférence des­tructive; le blocage des phases disparait, rendant l'interaction plus faible.

*Work supported by NRC

15 = 30DD9 CO2 Laser-Produced Ripple Patterns on NixP]_x

Surfaces. N. R. ISENOR, Univ. of Waterloo— When CO9- laser pulses of " 50ns duration and intensity of ~ 100­500 MW/cm^ produce plasmas on NixP^_x surfaces in oxy­gen-containing atmospheres, distinctive "ripple" pat­terns are etched into the surfaces. The ripple wave­fronts are normal to the E-field and vary in spacing from ~ liaser at normal incidence to ^ 0.5 A^aser for it polarization at grazing incidence. This dependence is found to be consistent with the diffraction of the laser light into a surface-travelling wave. A discus­sion based on laser-driven plasma oscillations is pre­sented .

1 6 : 0 0DD11 One Theorist's View of our Current Understanding of the Laser-Plasma Interface in Current Investigations of Inertial Confinement Thermonuclear Fusion using Lasers. T.W. JOHNSTON, INRS-Energie - While much of the earlier parametric instability analysis on uniform or weakly non uniform systems with application to in­tense laser irradiation of plasmas retains its intrinsic value, it seems that profile modification effects due to present day lasers require direct inclusion of ponde- ^omotive effects and violent density variation. The WKB era is nearly over and strong nonuniformity is a dominant feature now. Current trends along these lines will be reviewed with some thoughts for the near future. Some key words are surface waves, surface stability, surface solitons, nonlinear stimulated Brillouin scat­tering.

16:15DD12 Comportement du seui1 de l'instabilité absolue dans un plasma inhomogène fini. V. FUCHS et G. BEAUDRY, direction Sciences de base, IREQ, Varennes, Québec, Canada J0L 2P0 — On montre que le système d'équations décrivant l'épuisement non-linéaire d'une onde-pompe dans un plasma inhomogène fini atteint un état d'équi­libre non-stationnaire caractérisé par la rotation des amplitudes complexes des deux ondes de désintégration.Le décalage en fréquence qui en suit est une valeur pro­pre de l’équation pour la phase totale qui, contraire­ment à un plasma homogène, ne se bloque pas. Un nou­veau mode apparaît à chaque fois que la longueur norma­lisée Λ du plasma s'accroît de π/2. Nous présentons la courbe de seuil de l'instabilité absolue comme fonc­tion du gradient de la mésadaptation en longueur d'on­des et de la longueur du plasma. Les résultats sont corroborés par les résultats de calculs numériques faits sur le système d'équations temps-espace.

TUESDAY, JUNE 21, 1977 ROOM 202Chairman: R. M on ta lb e tt i

13 = 30DEI Theory for the Generation of Pc 5 Micro­

pulsation Activity. G. ROSTOKER and H.-L. LAM, Univ. of Alberta, Inst, of Earth and Planetary Physics. —In this paper the relationship between morning sector Pc 5 activity and the westward auroral electrojet will be discussed. It is found that Pc 5 oscillations may be understood as the combined effect of oscillations in the strength of the electrojet and in the position of its borders. It is shown that the magnetosphere- ionosphere current system including the ionospheric electrojet can be modelled by an LCR-circuit, and it will be demonstrated that earth induction plays an important role in determining the phase and polar­ization characteristics of the pulsations in the HZ- and DZ-planes.

BALFOUR W. CURRIE SYMPOSIUM - CONTRIBUTED I

13:^5DE2 Longitudinal Characteristics of Energetic

Electron Precipitation in Coniunction with Pc 5 Micropulsation Activity. J. V. OLSON, G. ROSTOKER and K. KAWASAKI, Univ. of Alberta, Inst, of Earth and Planetary Physics. — Magnetometer and riometer data from the University of Alberta IMS array have been used to study the character of high energy electron pre­cipitation during periods of large amplitude Pc 5 micropulsation activity. It is found that oscillations in the riometer signal often occur in conjunction with Pc 5 pulsations, however many cases are found where the Pc 5 fluctuations are not accompanied by concurrent riometer variations. The variations in phase of the micropulsation signal in the east-west direction will be discussed in terms of modulation of the ionospheric conductivity by energetic electron precipitation.

26

lit: 00DE3 M a tr ix and Stokes Vecto r Representations o f

Detectors fo r P o la rized Waveforms, w ith Some A pp lica ­t io n s to Te lese ism ic Waves and ULF Magnetic F ie ld s ,J.C . SAMSON, N.R.C. -- A problem which is fundamental to the in te rp re ta t io n o f m u lt iv a r ia te tim e-se ries is to

determ ine whether a given se rie s has c e rta in temporal and sp a t ia l fea tu res o r p o la r iz a t io n s . Detectors fo r po la rized waves can be designed in the frequency domain using the three-square spec tra l m a trix and the a lgebra o f non-negative herm itean m atrices , and a lso by using a nine-dimensional Stokes vecto r-a lgeb ra . In the Stokes vec to r-a lgeb ra , the detec to rs a re simple in ne r products in a re a l vec to r space, and are com pu ta tio na lly ve ry e f f ic ie n t . Some of the de tec to rs should be e sp e c ia lly usefu l in de tec ting te le se ism ic waves, such as Ray le igh waves, which are ' l in e a r ly ' p o la rized in a u n ita ry space, and fo r de tec ting po la rized ULF magnetic pu lsa tio ns contaminated by broad-band, unpo larized no ise.

l4 :15ΡΕ|* A Model fo r Oblique Propagatio n during T IP s .

G.F. LYON Uniy, o f Western O n ta rio -- I f a

T ra v e ll in g Ionospheric D isturbance is considered to cause a plane surface o f equal e le c tro n d ens ity to d is to r t in to a moving s in u s o id a l ly corrugated su rface , then re f le c t io n from such a surface is e a s i ly tre a ted . For one-hop propagation over a given ground range and fo r g iven TID parameters the changes in frequency, azimuth and e le va tio n o f the rece ived s igna l may be s im p ly p red ic ted . With reasonable assumptions the e ffe c ts o f m u lt ip le

simultaneous TIDs may be taken in to account. Some in te re s t in g p red ic tio n s from the model are d is ­cussed and comparison is made w ith experim enta l observa tions over the Ottawa-London path.

lit : 30DE5 A t - type Absorption: A Sensitive Tco­nique For monitoring ülb'ü. üïc’Li ki a U íJDI??. Laurentlan University, Sudbury, Cntarlo,An At - type absorption study was undertaken using 3-33 MHz CHU transmitter at Ottawa, over a b-25 km 'path. Some results are discussed.

15:00Latitudinal and Seasonal Variations of 5577A

Airglow Emission.* R. KHANEJA and L.L. COGGER, Univ. of Calgary— A study of the 5577A airglow using data from the ISIS-2 satellite has identified the main global features to be an equatorial minimum and a pronounced midlatitude maximum. The position of the midlatitude enhancement varies with season, occurring near 39 degrees geographic latitude in the winter and near 30 degrees in summer. The intensity of this feature exhibits a large semiannual variation with maxima in April and October which are about four times the minima in January and July. A seasonal variation of the intensity of the midlatitude enhancement has also been observed: it is about 1.6 times larger in winter than in summer.

*Supported by the National Research Council of Canada.

15=15DET Thp Radiative Lifetime of the Meinel OH

bands. E.J. LLEWELLYN, I.S.A.S., Univ. of Saskatchewan■The interpretation of many atmospheric pro­cesses, particularly in the stratosphere, re­quire an accurate knowledge of OH' radiative lifetime. Recent studies1»2 have indicated values that could extensively modify the at­

mospheric models. New measurements of some important atmospheric parameters are presented and compared with the values predicted by the extreme range of the radiative lifetime. A new interpretation of existing laboratory studies is also presented and used to infer a new value for the radiative lifetime of 0H^.1. F.H. Mies. J. Mol. Spectrosc. 53. 150,

1974 .2. A.E. Potter, R.N. Coltharp and S.D.

Worley. J. Chem. Phys. 54. 992, 1971.

15:30DE® A Wide-Eyed Look a t Radio Meteor Echo

S tru c tu re . R.W. HERRING, Department o f Communications, Communications Research C en tre , Ottawa, O n ta rio ,Canada.--The d if f r a c t io n p a tte rn s o f a rad io meteor echo propagated over a 911 km path a t a frequency o f about 22 MHz has been s p a t ia l ly sampled and recorded

using a 1.18 km l in e a r antenna a rra y . The temporal and sp a t ia l v a r ia t io n s o f the recorded am plitudes and phases were examined, and the sp a t ia l F o u r ie r t ra n s ­forms o f the data were computed to y ie ld angu la r spectra , o r in fo rm ation on echo am plitude as a func tion of angle o f a r r i v a l . The angu la r spectra showed evidence of a reso lved secondary echo near the end o f the echo l i f e . Ana lys is ind ica ted th a t th is secondary

echo could have been due to a t r a i l caused by a f ra g ­ment from the meteoroid th a t generated the main echo t r a i l . The observed motions o f the deduced main and

secondary echo re f le c t io n po in ts could be exp la ined on

the basis o f t r a i l ro ta t io n s caused by v e r t ic a l shears in the n eu tra l winds.

15:L5DE9 Effect of Atmospheric Turbulence on Sound Inter­

ference produced by a boundary, G.A. DAIGLE, Physics Dept,, Carleton University, Ottawa, Ontario. - When sound propagates through turbulence caused by wind and temperature variations, it exhibits fluctuations in phase and amplitude. If a boundary is present the in­terference pattern between direct and reflected waves is therefore degraded to an extent that depends on the par­tial correlation between the two waves - which in turn depends on the correlation length for meteorological fluctuations of the medium. Previous theoretical work has been extended to include this partial correlation between the two waves as well as adapting calculations of fluctuations in phase and amplitude of a spherical wave. The theory now also includes the explicit calcu­lation of the fluctuating index of refraction from the fluctuating values of temperature and wind speed. The above allows the sound pressure level at a point above the boundary to be computed quantitatively. Finally the theory is compared with simultaneous acoustical and meteorological measurements.

16:00DE1° Atmospheric Circulation, 60-110 km,at Saskatoon (1974-5 ). J . B. GREGORY and A.H. ΜΑΝΞ0Ν, I.S.A.S., UnTv. of Saskatchewan, Saskatoon"! — Radiowave drift observations were made daily from September 1974 to April 1975, near Saskatoon, Canada. Winds, 60-110 km, for selected periods were subject to spectral analysis, revealing wave energy at 2-3, 4-5, and >10 days. Coherence of motion in the mesosphere, e.g. 52-100 km, was estab­lished for several periods. The stratospheric warming of early January 1975 was marked by significant correlation of winds from strato­sphere (20 mb) to upper mesosphere (=85 km). Deductions from thermal winds show that as the stratosphere warmed, the mesosphere cooled. More generally, the upper mesosphere, 76-90 km, poleward of 52°N throughout December and January and to mid-February showed a 'cooling trend', and was cooler than in previous years.

27

TUESDAY, JUNE 21, 1977 ATOMIC PHYSICSROOM 129Chairman: .M. Ke

13:30DF1 The Canadian Primary Standard of Time and Freauency

C.C. c o s t a i n, a .g . mu ng all and H. d a a m s, N ationa l Reôea/tc/i Council Canada

In nearly two years of continuous operation, the performance of the NRC CsV, a long beam cesium primary standard of time and frequency, has exceeded that expected from evaluations^. The rms error during this period was 0.3 us, measured against the International Atomic Time Scale, and much of this error can be attributed to seasonal variations in the propagation of the Loran C 100 kHz signals used in the comparison. The absolute accuracy is 5 x 10”*\ or close to 1 U sec/year, and the stability is higher than can be measured at present. To overcome the difficulty of measuring the most accurate device in the world, three more primary cesium standards are under construction. Satellite time transfers with 1 ns precision to the BIH in France, NBS in the U.S.A. and PTB in Germany are under discussion. The significance of 1 ns accuracy in electronic navigation, and of parts in 1011* accuracy in experiments on the time variation of fundamental constants will both be discussed.

A.G. Mungall, H. Daams, D. Morris and C.C. Costain, Performance and Operation of the NRC Primary Cesium Clock, CsV. Seventh Annual PTTI, December 1975.

lU : 15DF2 S ino le Photon Emission From Rubidium Follow ing

Double K-Shell Io n iz a t io n 1 G. DUR0CHER, J.S .C . McKEE,D. RAMSAY and S .F .J . WILK, Cyclo tro n Lab. Un iv. of Manitoba -- At the U n iv e rs ity o f Manitoba C yc lo tron Labo ra to ry we have stud ied s in g le photon em ission fo llo w ing double K-shell io n iz a t io n o f rub id ium using

the P .I.X .E . technique p re v io u s ly d e sc rib ed l»2 *3). We are ab le to put an upper l im i t on the cross section fo r th is e ffe c t and d iscuss i t s re levance to data obtained by G entry e t a l4 ) concerning element 126.

^ J.S .C . McKee, C.P. Randell and S .F .J . W ilk ,J. Phys. D. 9 L 69,(1976).

^ C.P. R ande ll, J .S .C . McKee and S .F .J. W ilk ,J. Phys. G. 2 L 69 (1976).

^ C.P. R ande ll, M.Sc. Thes is , U n iv e rs ity o f Manitoba (1976).

R.V. G en try , T.A. C a h i l l , N.R. F le tc h e r, H.C. Kaufman, L.R. Medsker, J.W. Nelson, R.G, F lo c c h in i,

Phys. Rev. L e t t . 27, 11 (1976).

Supported by the NRC o f Canada.

1U:30DF3 Orientation of Fast Tons Excited by Grazing

Surface Collisions.* H.G. BERRY, G. GABRIELSE, and A.E. LIVINGSTON, Univ. of Chicago and Argonne National Lab^-- Anisotropic excitation of atomic states in general produces both oriented and aligned atoms or ions. The orientation and alignment can be measured by observ­ing the circular and linear polarizations of the light emitted by these excited states. We have measured the relative Stokes parameters of polarized light emitted fo^lowi^ig the ne^r-grazing-angle scattering of 1.0 MeV He , Ne , and Ar ions from solid metallic surfaces.We have established that the circular polarization of light emitted by the scattered ions, and hence the ion orientation, is strongly dependent on the ion scattering angle. The orientation is maximum for ions experiencing nearly elastic collisions with the surface. The linear polarization is small compared with the circular polar­ization for all scattering angles. Results will be presented for various atomic states. Possible applica­tions for such sources of highly oriented fast ions in atomic physics experiments will be mentioned.*Supported by U.S. ERDA and NSF.

iL : 1+5DFL Core Polarization Effects In Atomic Systems.*

R. A. MOORE, Univ. of Waterloo, and C. F. LIU, Kaohslung Teacher*s College.— A semi-classical, self-consistent and unified formulation of core charge polarization effects in atomic systems is presented. The method applies to atomic polarization in electric fields, to the total effective one-electron potential energy for the valence electron, to the effective dipolar scatter­ing interaction, to the shell model in ionic crystals, and to the conduction electron states in metals. The

expressions are presented in forms that can be readily assimilated into standard calculations. Some results are compared with previous calculations for atomic cesium. It appears that we have a valid and useful formulation and that, at least for atomic cesium, the major portion of the correlation effects, to be added to a Hartree-Fock calculation, are given simply by the dipolar contribution.

*Supported in part by the National Research Council of Canada.

g gDF5 Ad 5s -» 4d 5p Transitions^ in the Fifth

Spectrum of Indium (In V) and the Sixth Spectrum of Tin (Sn VI). R.P. SRIVASTAVA, Y, N. JOSHI and TH. A.M. VANKLEEF1. St. F. X. Univ,— The spectra of quadruply ionized indium and five times ionized tin have been observed on 10.7 m and 6.65 m normal inci­dence spectrographs In the region 700 A - 1500 A. The source used was a sliding spark operated under varied experimental conditions to discriminate among different stages of ionization. All the energy levels belonging to 4d®5s and 4d®5p configurations have been establish­ed. Over 275 lines are now classified in the In V spectrum and over 250 lines in the Sn VI spectrum.^The parametric level-fitting calculations of Poppe confirm both these analyses.

1. Permanent Address: Zeeman Laboratory, University of Amsterdam, The Netherlands.

2. R. Poppe, Physic·. _75, 341, 1974.

15:30DF6 Beam-Foil Lifetimes and Spectra of Xenon V-VIII*

K. E. D0NNELLŸ7 E7 H. PINNINGTON ancT J. A. KERNAHAN, Univ. of Alberta — Radiative lifetimes for the ions Xe V-VIII have been measured in the range 400-1000 Δ, using a beam-foil light source. Although the spectra of these ions are poorly known, lifetimes of assigned transitions are In good agreement with isoelectronic and homologous trends. Suggested assignments are made in Xe VI on the basis of isoelectronic wavelengths and homologous f- values in other noble gases. In Xe VII the 5s2 *Sq - 5s5p 3Pi intercombination decay rate has been measured.A theoretical study of this transition rate in terms of the LS-interaction determined directly from the known separations of the 3P levels predicts a ratio of Xe VII 5s5p 3Pj and toj lifetimes in good agreement with our measurements.

*Supported by the National Research Council of Canada and the Province of Alberta.

2 8

DF7 Measurements of Atomic Oscillator Strengths Using Beam-Foil Spectroscopy.* E. H. PINNINGTON, K. E. DONNELLY and R. L. BROOKS, Univ. of Alberta — One of the major justifications for measuring atomic f-values at the present time is to provide a test of the latest generation of methods for computing accurate atomic wavefunctions. Of particular interest is the f-value variation along an isoelectronic sequence for transi­tions from or to states in which configuration inter­action is important. Illustrative examples will be taken from recent work at Edmonton. Naturally the usefulness of an experimental f-value increases with its accuracy. A brief review of current procedures for estimating the accuracy of beam-foil f-value measurements will be given.

1 5 ^ 5

*Research supported by the National Research Council of Canada and the Province of Alberta.

TUESDAY, JUNE 21, 1977 ROOM 127

Chairman: J. Vanderkooy

13:30DG1 Uniaxial Stress Deoendence of the Fermi Surface

of Rhenium.* F.W. HOLROYD, E. FAWCETT and J.M. PERZ, Unfv. of Toronto— The large anisotropy of the limiting electronic attenuation of longitudinal ultrasonic waves in Re1 suggests that its Fermi surface has a very ani­sotropic deformation-tensor. In order to explore this anisotropy directly, we have made simultaneous measure­ments of quantum oscillations in the torque and magneto­striction. For stress σ along the hexagonal axis the resultant values for the stress dependence, d2.nA/da, in units of 10-6 bar-*, for various orbits of area A, range from approximately +4 (5th band hole ellipsoid), -0.3 (6th band hole dumbbell) and -0.8 (7th band hole dis­torted sphere), to +50 (9th band electron torus).

!c.K. Jones and J.A. Rayne, Phys. Letters 21, 510 (1966). *Supported by the National Research Council of Canada.

13 : U5DG2 Thermopower of the Linear Chain Mercury Com­

pound Hg? AsF&.* G. A. SCHOLZ, W. R. DAT ARS,D. CHARTIER and R. GILLESPIE, McMaster University — The temperature dependence of the thermopower of the linear chain mercury compound Hg2.86 s 6 was investi­gated along its two principal directions. The appara­tus measured the Seebeck e.m.f. of the small specimens which have to be handled in a dry-box and to which only mechanical contact can be made. Metallic con­duction is found which is electron dominated in the a, f> directions and hole dominated in the c direction. The temperature dependence observed in the thermo­power is explained using a free electron model in which the total thermopower is expressed as the sum of a diffusion component, dominating above 100K,and a phonon drag component, dominating at lower tempera­tures. The Fermi energy is calculated to be 4.6±0.5 e.V. and the Debye temperature is fixed between 60K and 90K. No metal-insulator transition was observed. However, a transition is observed around 190K in Sg and is thought to be due to ordering of the mercury atoms or to a change in unit cell dimensions.^Supported by the National Research Council of Canada

DF8 On the Calculation of Line Broadening Constants Using the Methods of Deridder and Van Rensbergen.* J.A. O’NEILL, Univ. of Alberta — The calculation of line broadening constants to oe used in the analysis of Stellar spectra requires an expression for the inter­atomic potential for collisions between the radiating and perturbing atoms. An unusual potential which reduces the interaction between the atoms to that between the perturbing atom and the valence electron of the radiator has been described by Roueff!, and an extensive tabulation of broadening constants for collisions with neutral Hydrogen and Helium perturbers calculated using this approach has been made by Deridder and Van Rensbergen. In this paper it will be shown that the approximations made previously in the calculation of line broadening constants using this potential are not valid for some values of n* and c, leading to a drastic revision of the importance of this potential.

E. Roueff, Astron. and Astrophys. 7_, A (1970).

*G. Deridder and W. Van Rensbergen, Astron. and Astrophys. Supplement 23, No. 2 (1976).

1 6 : 0 0

ELECTRONIC AND MAGNETIC PROPERTIES OF METALS

14:00P l a t i n u m Rhod i um A l l oys i n The rmoe1e c t r i c

The rmomét r y . R .E . BEDFORD, NRC -- As an o u t g r o w t h o f a

p rog ram conce rn e d w i t h p ro d u c i n g r e f e r e n c e t a b l e s f o r

P tRh a l l o y t h e rm o c o u p le s , t h e Seebeck emfs o f a l l o y s

c o n t a i n i n g 1, 5 , 6 , 2 0 , 30 , A 0 , and 100% Rh i n P t have

been measu red r e l a t i v e t o p u re P t f rom -50° t o 1600°C

w i t h an a c c u ra c y w i t h i n ± IpV a t t h e lo w e r t e m p e r a t u r e s

and ± 3pV a t th e h i g h e r t e m p e r a t u r e s . T h e re a r e s y s t e ­

m a t i c d i f f e r e n c e s be tw een th e em fs o f w i r e s o f d i f f e r ­

e n t o r i g i n . The t h e r m o e l e c t r i c powers o f t h e a l l o y s

r e l a t i v e t o P t a r e o b t a i n e d f rom p o l y n o m ia l f i t s o f

t h e emfs as f u n c t i o n s o f t e m p e r a t u r e . I t i s known t h a t

t e m p e r a t u r e s ( t £ y ) d e f i n e d by a P t l 0 R h / P t th e rm o co up le

on th e IPTS-68 between 630 °C and 106A°C d e p a r t f rom

th e rm o d ynam ic t e m p e r a t u r e s (T ) by a b o u t 0 . 5 °C a t 800°C.

From i n t e r c o m p a r i s o n s o f c o m b in a t i o n s o f t h e above

a l l o y s , we show t h a t s i m i l a r t e m p e r a t u r e s c a l e s based

upon them d i f f e r f rom b o th t ^ y and T in a s y s t e m a t i c

way. The u s e f u l n e s s o f P tRh a l l o y t h e rm o c o u p le s f o r

d e f i n i n g a c o n t e m p la te d s e c o n d a r y r e a l i z a t i o n o f t h e

IPTS-68 w i l l be d is c u s s e d .

14:15 D G AThe High-Field Electrical and Thermal Magnetoconduct-

ivlties of Pb. R. FLETCHER and M.R. STINSON, Queen’s Univ.- The limiting high magnetic field behaviour of the electrical and thermal magnetoconductivities of a Pb single crystal with B along [001] has been extracted from data taken in fields of up to 4.3T in the liquid ^He temperature range. The electrical conduct­ivity varies as B-2 in the limit of high fields, with the coefficient exhibiting a T5 dependence, the same as is found for the zero field resistivity. The analogous coefficient for the thermal magnetocónductivity shows a T 3 dependence but there is no zero field data avail­able for comparison. The lattice component of thermal conductivity has also been determined and is found to obey a T2 dependence only below 3K with a more rapid dependence between 3-AK.

lU : 30DG5Femii Diameters in Lithium*. R.J. Douglas,

S.L. Basinski, L.A. Gordon, and A.T. Stewart,Queen's Univ. Accurate measurements of the Fermi diameters in the [100], [110], and [111] directions in Li have been made by positron annihilation using a high resulution long slit angular correlation apparatus. The data show that the [110] diameter is about 25, larger than the diameter in the cubic direction, the latter being very close to free electron theory. Detailed analysis, including effects of higher momentum components of the electron wave function will be presented.

* Supported by the National Research Council.

Il» : 1*5Far Infrared Cyclotron Resonance Measurements

in Bi and Sb.’' C.S. KANG and J. VANDERKOOY, Univ. of Waterloo— The surface impedance of antimony and bismuth at 337p and 311μ has been studied in magnetic fields to 11.8 T. The bismuth data show hybrid resonances and dielectric anomalies. Model calculations show that details of the data are reproduced only when explicit account is taken of Fermi level variations with mag­netic field and non-parabolicity of the bands. Even so cut is strongly dependent on field in a manner similar to other experiments^. The antimony data show cyclo­tron resonances, propagating modes and a dielectric anomaly fairly independent of orientation. Details of a model are being prepared for some of these phenomena.

*H.R. Verdun and H.D. Drew, Phys. Cond. Matter 19, 371 (1975).

*Research supported by the National Research Council.

15:00 ni; 7 Spin-Orbit Interaction in Metals.* C. B. SO,

R. A. MOORE and S, WANG, Univ. of Waterloo— A model pseudopotential which includes the spin-orbit inter­action is developed from first principle considerations for the calculation of metallic and semiconductor prop­erties. First, an atomic model potential, which is, in general, more suitable than existing ones is determined by fitting to the energy levels of the low-lying atomic valence states and is then used in the construction of the model pseudopotential for the solids. It appears from the applications that we have made that spin-orbit effects are (a) not significant for the Fermi Surface distortions of the alkali metals, e.g., being about 5% for Cs, (b) also not significant for the lattice prop­erties of all the alkali metals, with the exception of being about 10% in the second order elastic constants of Cs and (c) very important in both the elastic con­stants and phonon spectra of Pb metal.

*Supported in part by the National Research Council of Canada.

15:15DG8 Hyperfine Fields at Fe Impurity Sites

in Co-based Heusler Alloys G] R] MACKAY,J. JUDAH, C. BLAAUW, W. Le IPER, Dalbousie Univ.--We have used the Mossbauer effect to measure the hyperfine fields at Fe sites in Co57- and Fe-·-doped samples of Co2MnX, with X one of the Group IVA elements Si, Ge and Sn. The values found were, respectively, H(Co57-* Fe57] = -117 kOe, -107 kOe and -118 kOe and H(Fe 5 7 ) = - 325 kOe, -300 kOe and - 290 kOe. It is clear that the Fe substitutes prefer­entially on the Mn sites. The difference in the hyperfine fields at the two Fe sites can be understood in terms of different near neighbour moment configurations.

15:30DG9 The Observation o f Magnetic Domain Wall P inning

in Iro n using Thin F ilm E lec tron M icroscopy*.P. GAUNT and C.K. MYLVAGANAM, U n iv e r s i t ÿ o f Manitoba. The coerc ive f ie ld o f many ferromagnets a r is e s because o f the p inn ing o f domain w a lls a t inhomogeneities in the m a te r ia l. Progress in deve lop ing d e ta ile d models o f the in te ra c t io n between domain w a lls and inhomoge­

n e it ie s has been s low 1 because magnetic data alone do

not g ive s u f f ic ie n t in fo rm a tio n fo r a c r i t i c a l te s t o f d if fe re n t th e o r ie s 2’ 3. Transm ission e le c tro n m ic ros­copy can, however, g ive a d e ta ile d p ic tu re both o f the morphology o f the inhomogeneities and o f the w a ll p inn ing process1· ’ 5. P re lim in a ry re s u lts showing the p inn ing and unpinning o f domain w a lls a t copper p re­

c ip ita te s in iro n , w i l l be presented and discussed.

3L. Néel, Cah iers de Physique, 4, No. 25, 21-44, 1944. 2D .I. Pau l, AIP Conf. P roc ., 29, 545, 1975.3P. Gaunt and C.K. Mylvaganam, J. A p p l. Phys., in press, 1977.

"A. R ile y and G.A. Jones, IEEE Trans, on Magnetics,

MAG 9 , 201, 1973.5P. Gaunt, Physica, in p ress, 1977.

*Work supported by Nationa l Research Council o f Canada.

15:!*5Transition spin-Pelerls de premiere espèce

dans un modèle dHeisenberg antlferromacnétiaue liné­aire. Y. LEPINE et A.CAILLE, U. de Sherbrooke .Une chaîne linéaire antiferromagnétique d ’Heisenberg est traitée dans l’approximation de Hartree-Fock .Le couplage élastique combiné à 1’intéraction anti­ferromagnétique entre les spins provoque une dimé­risation spontanée de la chaîne aux basses tempéra­tures. Nous trouvons que cette dimérisation peut être décrite comme une transition de phase de premiè­re ou de seconde espèce si on tient compte du carac­tère exponentiel de 1 ’intéraction d ’échange et d ’une force élastique de courte portée. 2^e s résultats sont une généralisation de ceux de Béni qui obtient une transition uniquement de seconde espèce à partir d ’une énergie élastique quadratique et d ’une dépen- dence linéaire pour 1 ’intéraction d ’échange.

L.N. Bulaevskii, Soviet Physics JETP 17,684 (1963)2 G. Beni, J. Chem. Phys. 58, 3200 (1973)* Recherche subventionnée par le C.N.R.C.

1 6 : 0 0

1X111 E la s t ic Constants o f Holmium between 80K and 140K. A.M. SIMPSON and W. A. ROGER, Dalhousie U n iv .—

The v a r ia t io n in the e la s t ic constants Cm .Cj j , C^t,, and C66 o f a s in g le c ry s ta l o f Holmium has been measured

as a function o f temperature between 80K and 140K w ith a r e la t iv e accuracy o f about one p a rt in 10s . P a r t ic ­u la r a tte n t io n was paid to the reg ion near 95K where

an anomalous peak in the u lt ra s o n ic shear wave a tten u ­a tio n has been observed.1>2 ftn accompanying d ip in the

va lue o f C.i, o f magnitude ACku/G.u=3>< 10"3has been obser­ved. No anomalies were observed in the o th e r e la s t ic constants in th is reg ion w ith in the accuracy o f the measurements. I t has been suggested th a t the anomalous p ro pe rt ie s occur when the an tife rrom agne tic sp in s p ira l s tru c tu re becomes commensurate w ith the la t t ic e when the s p ira l angle between ad jacent planes becomes 45°.The e la s t ic constants then con ta in in fo rm a tion as to which in te ra c t io n s in the metal are s e n s it iv e to th is o rde ring .

^A. M. Simpson, Μ. H. Je ric ho , and M. C. J a in , Can. J. Phys. 54, 1172 (1976).M. C. Lee, R. A. T rede r, and M. Levy, J. Phys. Chem. So lid s 36, 1281 (1975).

16:15

Low Temperature Thermal Expansion of Holmium D. A. TINDALL, M. 0. STEINITZ and M. PLUMER, St. F. X. Univ. - As reported at this meeting by Simpson &Roger, the nature of the elastic anomalies found in Holmium around 95K is slowly becoming clear. We have made thermal expansion measurements on a piece cut from the single crystal used in their ultrasonic velocity measurements, in order to enable the con­version from pulse time-of-flight data to velocity.We report the null result of a search for associated anomalous changes in length and/or coefficient of thermal expansion, which might indicate the occurrence of a phase transition.

30

TUESDAY, JUNE 21, 1977 DIVISION OF PHYSICS EDUCATION WORKSHOP

ROOM 125Chairman: .H. 31rn e

13:00 - 17:00dh the development o f scientific understanding

The Division of Physics Education, the Saskatchewan Teachers' Federation and the University of Saskatchewan will present jointly a Workshop which has been organized by the American Association of Physics Teachers. The topic of the Workshop is the work of the Swiss psychologist Jean Piaget on the development of the ability to grasp concepts which are needed in science. Although much of Piaget’s work is concerned with the early development of conceptual ability in young children, many of the concepts treated by Piaget are relevant to the senior years of school and the junior years at university. The Workshop consists of a series of modules which contain audio-visual and other material, each module referring to one of the basic concepts in science. The Workshop will be introduced by Mr. T. Campbell, Illinois Central College, Peoria, Illinois on behalf of the American Association of Physics Teachers.

TUESDAY, JUNE 21, 1977 ANNUAL BUSINESS MEETINGS16:45

ROOM: 202 Division of Aeronomy and Space Physics CHAIRMAN: G.G. Shepherd

129 Division of Atomic and Molecular Physics J.-D. Carette

103 Division of Condensed Matter Physics W.R. Datars

126 Division of Medical and Biological Physics J.C.F. MacDonald

130 Division of Nuclear Physics S.K. Mark

127 Division of Optical Physics G. Stegeman

165 Division of Particle Physics Y. Takahashi

125 Division of Physics Education D.C. Baird

128 Division of Plasma Physics H.M. Skarsgard

107 Division of Theoretical Phvsics H. Umezawa

TUESDAY, JUNE 21, 1977 SYMPOSIUM OF THE DIVISION OF PHYSICS EDUCATIONROOM 107Chairman: D.C. Baird

19:30Dll The Universities’ Expectations of High School Physics

M.w. JOHNS, ttcM asten U n lv e /u ity

20:00

DI2 The Saskatchewan Core Curriculum in PhysicsH.H. BIRNIE, U n iv e r s i t y oft S a s k a tc h e w a n

2 0 : 45DI3 The Ontario Core Curriculum in Physics

J.R. STEVENS, U n iv e r s i t y <7/5 G uetph

21:15DI4 The Saskatchewan Core Curriculum: the High School Teachers' Point of View

E.w. ROBERTSON, WaLter M tvilay C o lleg ia te In s titu te , Saskatoon

31

WEDNESDAY

ROOM 107 Chairm an:

JUNE 2 2 , 1977 NUCLEAR PHYSICS I I

J . T . Sample

9:00EA1 Electrofission of Light Elements

A . E. LITHERLAND, U w iw u lty ojj Toronto

9:45EA2 Pionic Effects in Low Energy Nuclear Physics

f .c . KHANNA, Chalk ZivzA NucI& oa LabanatofUQA

10:30EA3 Proton-Nuclei Interactions at Intermediate Energy

W.J. MACDONALD, U iu ve A iity otf Atb z ita and TRILIMF

11:15EA4 Nuclear Fireballs in Heavy Ion Collisions

G.D. w e s t f a l l, Laurence BeAkeley LabotiaCoKy

WEDNESDAY,

ROOM 103 C ha irraan :

JUNE 22, 1977 LOW DIMENSIONAL SYSTEMS SYMPOSIUM

W.R. Datars

9:00EBI Theoretical Concepts in the Study of Quasi One Dimensional Materials

B. BERGERSEN, lly iive /i& lty ojj S ic tiA h Columbia

A review is given of concepts which are important for an understanding of the equilibrium properties of quasi one-dimensional materials and in particular of semi-donductor to metal transitions in such substances. The charge density wave instability of a single one dimensional electronic band is first discussed in mean field theory. It is then argued that the naive picture this gives must be modified to take into account the effects due to disorder, fluctuations, weak inter-chain couplings and electron-electron interactions.The importance of partial charge transfer is emphasized and it is shown how partial charge transfer can give rise to a minimum in the cohesive energy. The possible role of charge transfer transitions is discussed.

9:45EB2 Preparation and Study of Organic Metals

L. WEILER, iln ivzsu iZ y o BrUtL&h Columbia

A review of the history, preparation and physical properties of one-dimensional organic metals will be given. Particular emphasis will be given to synthesis of TTF-TCNQ and the study of its properties including conductivity, structure and susceptibility. The interpretation of this data based on simple models will be presented. The application of MO theory, ionic fluctuations, polarizability, molecular geometry, packing and ionic effects to these systems will be discussed. Efforts to produce new materials with higher room temperature conductivities or materials devoid of metal-insulator transitions will be given.

10: 30 EB3 The Role of Librons in Quasi ID Organic Conductors

H. MORAWITZ, IBM Research Labox.a£o>iy, San Joóe., Calico nyila.

The lattice dynamics of molecular charge transfer crystals such as the class of conducting TCNQ salts involves both translational ("phonons") and rotational ("librons") degrees of freedom. At general (low symmetry) points of the Brillouin zone the rigid body motion of the molecular units is strongly hybridized, in parti­cular at degeneracy points of the lattice spectrum. We discuss the implications of this important difference of molecular solids with conduction bands formed from delocalized pi-molecular electrons as opposed to the more familiar case of inorganic (atomic, ionic) solids, in which only translational displacements (phonons) enter. Specifically we will show that the occurrence of degeneracies of the finite frequency libron branches (at q=0), which have little dispersion, and the longitudinal and transverse acoustic phonons near q=2k^ lead to definite predictions for the character of the softening Peierls mode observed in diffuse x-ray scattering and neutron scattering. Implications of the role of libron-conduction electron interaction for electron scattering times, the temperature dependence of the conductivity and thermal expansivity will also be discussed.

32

EB4 Phonons dans les systèmes de dimension réduiteD. CHEEKE, \lYÙ.oeJU>Jcté d e Shzn.bn.ooke,

On limitera la discussion aux systèmes de type unidimensionnel (TCNQ, KCP etc.) et bidimensionnel (type NbSe2). D'une part, on exposera l’intérêt fondamental d'études acoustiques dans de tels systèmes et les principales prévisions théoriques. D’autre part, on passera en revue les résultats expérimentaux obtenus a Sherbrooke et ailleurs par differentes techniques complémentaires (neutrons, ESR, ultrasons, etc.). On expliquera finalement les domaines d'activité future probable.

11:15

WEDNESDAY, JUNE 22, 1977 THEORETICAL PHYSICS

ROOM 130Chairman: R. Sk inne r

9:00EC1 Present Status of Gravitational Theory

M. WALKER, U niveA iiXy o$ A lb w ta and Max Planck In s titu te , Munich

9:45EC2 A Classification of Sub-groups of Conformal Group of Space Time and Its Application to Physical ProblemsG. PATERA, U n iv c u itc dc M ontreal

10:30 Break

10:45EC3 Theory of Soliton; Nonlinear Waves in Dispersive Media

M. WAD AT I, Univ u n ity ofj k ib u ita and Kyoiku U n iv u u ity , Tokyo, Japan

The study of nonlinear waves stemmed from the observation of solitary wave on a canal in the middle of the 19th century, has made a remarkable stride in the last decade. Intensive researches on nonLinear waves occurring in the various fields of physics have provided us with new physical concepts such as "soliton" and "envelop soliton" and also very powerful mathematical tools such as "Inverse scattering method" and "Backlund transformation". Soliton is a localized component of nonlinear wave and behaves as if it is a particle. Mathematically we can define "soliton system" as a completely integrable system. The soliton system has a remarkable property as there exists an infinite number of conservation laws. Recently, a one-to-one correspondence between conservation law and infinitesimal transformation (symmetry) has been explicitly shown. The relationships among quantum topological number, vortex solutions (e.g. magnetic flux in superconductor and dislocation in crystal) and soliton will also be discussed.

11:30Ecl* Neutron Charge Radius and the Quark

Parton Model.* A. NIEGAWA**and D. KIANG, Dalhousie Univ.--In the framework of the val­ence-sea version of the quark-parton model, we obtain an inequality which relates the neutron mean-square charge radius to the deep- inelastic electron-nucleon structure functions. A numerical estimation of this inequality using available data indicates that it is doubtful the correct neutron charge radius can be obtained in this type of quark-parton model commonly in use.‘Supported in part by the National Research Council of Canada.

“ Killam Postdoctoral Fellow. On leave of absence from the Physics Department, Osaka City University, Osaka, Japan.

11:U5 EC 5 Gravitational Time in a Projective Space

with Null Cones. C.C. CARBNÖ,* R. SKINNER and J.M. NESTER, Univ. of Saskatchewan.— Freely falling part­icles may determine a projective connection Γ in space-time, and light rays fix a conformal metric f a The projective connection, if it exists, and the conformal metric can be measured independently by the Kundt-Hoffman procedure. Can one extend these along a path to a connection, possibly non-metric and with torsion, and a metric that define gravitational time in the sense of Marzke and Wheeler or Ehlers?

One can do this only if the projective connection and a metric representative of the conformal equivalence class satisfy sixteen relations. In general, the torsion is non-zero. Such gravitational time can be defined in a torsion-free space only if the projective connection and the representative metric satisfy additional constraints.

*Supported by an N.R.C. postgraduate scholarship.

12:00EC6 The Poincare Group and Its Gauge Theory.

J.M. NESTER,* Univ. of Saskatchewan/— In a general spacetime with metric one can express quantities in terms of their components with respect to orthonormal frames. Physics must be independent of the choice of reference frame i.e. invariant under local Lorentz "rotations” and translations (i.e. diffeomorphisms). An examination of this generalization of the Poincaré group to general spacetimes shows the necessity for the introduction of compensating fields for rotations and translations. Because of the great interest in the use of gauge theory to explain fundamental inter­actions, these results are important in treating gravity as a gauge theory of spacetime symmetries. This analysis shows that Einstein’s theory is a gauge theory only for translations while Kibble's theory is a gauge theory for the "Poincaré group".

Supported by NSF grant GP-43708X

33

WEDNESDAY, JUNE 22, 1977ROOM 128Chairman: A.A. Offenberger

PLASMA PHYSICS I I I

9:00EDI Gas Shell Targets for Laser Fusion.* J. KWAN,

K. FONG and B. AHLBORN, Univ. of British Columbia.-- The properties of a gas shell target generated with a laser blast wave prepulse (energy E0) in a background gas (density p0) are discussed with an analytical model. The ’’target" gas inside the shell is the rest of the laser fireball established initially and the high den­sity shell is the shock compressed background which sur­rounds the laser plasma at a later time. It is assumed that the main laser pulse establishes an ablation front at the outer edge of the gas shell, driving a shock ra­dially inwards which compresses the target gas inside.We find that the maximum pressure generated at the cente center scales as pm^w2/3 At6/5 E0"^/5 pQ-4/15^ where W is the power of the main laser and At the time interval between prepulse and main pulse.

9 = 5EDit U lt r a fa s t In f ra re d D iagnostics fo r the COCO-II

Laser System. P. JAANIMAGI*, N.R. I SENOR* and M.C. RICHARDSON, N.R.C. In te ra c t io n s tud ies o f in tense sho rt d u ra tio n C02 la s e r pulses w ith so lid ta rg e ts are a t p resent l im ite d by the temporal re s o lu t io n o f con­ven tio na l photon drag and p y ro e le c tr ic in fra re d de­te c to rs (bandwidth 1 GHz). An a lte rn a t iv e approach fo r re a l time measurement o f 10 um ra d ia tio n is based upon upconversion in p ro u s t ite , y ie ld in g a bandwidth l in . ic exceeding 200 GHz. A novel Q-switched Nd:YAG la s e r has been synchronised to the C0C0-II la s e r system, and the upconverted ra d ia t io n a t 0.96 um analysed using conventiona l high o p tic a l reco rd ing techniques.

* U n iv e rs ity o f W aterloo.

*Supported by the N.R.C.

9:15Génération et detection de microcibles liquides

destinées aux interactions laser. G. SAINT-HILAIRE et Z. SZILI, Direction Sciences de base, IREQ, Varennes, Québec, Canada, J0L 2P0 — Un dispositif électrostati­que simple a été conçu afin de créer des microsphères dans une chambre d'interaction laser. La pointe d'une aiguille conductrice émerge de quelques millimètres au- dessus de la surface d'un liquide (huile) où un fort champ électrostatique polarise celui-ci et extrait les gouttelettes une à une. En variant le champ électrique et la hauteur émergente de l'aiguille, on varie le dia­mètre et la fréquence de production des gouttelettes.Ce dispositif électrostatique ne requiert aucun tube ca- pilaire, ni réservoir à pression contrôlée, ni transdu­cer sonique, ni pulseur haute tension. Un dispositif optique permet l'étude de ces microcibles et de leurs trajectoires dans la région d'interaction avec le fais­ceau laser.

1 0 : 0 0ED5 Charged P a r t ic le A na lys is o f High Power CO?

Laser Target In te ra c t io n . D.M. VILLENEUVE*, G.D. ENRIGHT, N.R. I SENOR* and M.C. RICHARDSON, N ationa l Research Counc il o f Canada. Measurements o f ion and e lec tro n em ission from p lana r ta rg e ts ir ra d ia te d by 1 ns, 10.6 pm la s e r pulses from the COCO-11 la s e r system are reported fo r power d en s itie s up to 2 * 1 0 11+ W/cm? . Thermal and non-thermal ion components were analysed using a Thomson parabola spectrometer and

charge c o lle c to rs , w h ile PIN de tec to rs were used to record the superthermal e le c tro n em ission. Fast ions w ith energ ies %1 MeV have been observed.

* U n iv e rs ity o f W aterloo.

10:30EDo UV Photoion Density Measurement Using a High

Pressure Langmuir Probed J . SANTIAGO and A.M. ROBINSON, U n iv , o f A lb e rta - Volume io n iz a t io n produced in A r by uv photoions was measured using a fa s t ro ta t in g Langmuir probe. The uv ra d ia tio n was obtained from an e le c t r ic d ischarge and co llim a ted to produce a c y lin d r ic a l plasma. Measurements were performed fo r pressures o f 100, 200, 400 and 600 T o rr and d istances o f 2.5 to 10.2 cm from the d ischarge. Plasma decay was observed from 50 to 350 ps a f te r the d ischarge was f i r e d and was a t t r ib u te d to ra d ia l expansion by ambipolar d if fu s io n and volume recombination. By an

e x tra p o la tio n process, the i n i t i a l photoion d en s ity can be obta ined; i t s d is tance dependence suggests two- photon io n iz a t io n o f A r. The re s u lts a re a lso compared to o th e r measurements found in the l i t e r a t u r e .

9:30ED3 Rubv Laser Diagnostics Accurately Synchronized

with the Plasma Created by a Short Pulse CO Laser. B. GREK, T.W. JOHNSTON, F. MARTIN, H. PEPIN, FT RHEAULT, INRS-Energie - The synchronous mode locking and pulse selection of the output from a short pulse CO^ laser (1.7 nsec, 10 J) used for target irradiation and that of a shorter pulse (30 - 50 psec) diagnostic ruby laser has been achieved. The active mode-locking components for each laser oscillator are driven from a common source. Time displacement can be obtained readily with an electrical delay line and relative jitter is certain­ly better than 200 psec. Sequences of Schlieren photo­graphs and, hopefully, holographic interferograms of the CO^ laser produced plasma will be presented demons­trating some of the capabilities of the system. This work is supported by Negotiated Development Grant D-59 from the National Research Council of Canada and by in­dividual grants to Grek, Johnston and Pepin.

10:14 5Ton fnntainiiimt hv RadIo-Freauencv Fields. J.E.

FULFORD and R. E. MARCH, Trent Univ. and R. F. BONNER, Rockefeller llniv. —The containment of ions by radio-frequency fields appli­ed to a th r e e - d i m e n s io n a l quadrupole ion store (Quistor) has been examined in an integrated programme of experi­mentation and computer-assisted simulation study. The equations of motion for an ion in a conventional Quistor with hyperbolic electrodes permit ready calculation of ion motion leading to simulation of ion trajectories and collisions. The effects of charge and momentum transfer on ion motion and energy have been examined through both simulation and experimental observation.The experimental work has been extended to a study of geometric variation of the Quistor configuration with the objective of operational optimization of RF ion traps. A comparison is made of the operation of the Quistor at Ί 0 -2 Pa and at ~105 Pa; work is proceeding at this latter pressure on the development of trace detection for explosives and narcotics.

3*·

11:00EDS Observation schlleren et shadougraphy d'un plas­ma dense rf'hydrogène prndnlt par striction axiale.G-. SAINT-HILAIRE, C.R. NEUFELD, P. NOEL, A. ROBERT, Di­rection Sciences de base, IREQ, Varennes, Québec, Cana­da, JÓL 2P0 — Des observations, par ombrage (shadou­graphy) et déviation de faisceaux (schlleren), ont été faites sur une colonne dense^ (ne * 10^ cm2) de plasma d'hydrogène et d'hélium, produit dans une machine à striction a courant axial (Z-pinch). En utilisant un laser rubis (20 ns), les observations par déviation de faisceaux indiquent aucune déviation parallèle à la co­lonne de plasma, et une déviation faible (Θ < 2°) dans le plan perpendiculaire à celle-ci. Les observations par ombrage mettent en évidence la présence d'ondes de choc convergentes antérieures à la formation de la co­lonne, ainsi que les phases de compression et de détente, en fonction de la pression initiale. En raison du dia­mètre considérable de la colonne et de sa densité élec­tronique élevée, une très forte atténuation (> 15 db) du faisceau laser rubis se produit dans le plasma.

1 J. Mercier, C.R. Neufeld, P. Noël et A. Robert, Bull.Am. Phys. Soc. 21, 833 (1976).

11:15ED9 O ütica l Measurements o f Laser-Detonated Shock-

Haves in Thin L ith ium M ire s . J.C. SAMSON and A .J. ALCOCK, N.R.C. -- In te rferog ram s and shadowgrams of plasmas produced by focussing a 0.5 J, 1 ns, 1.06 pm laser-beam onto 100 pm l ith iu m strands in d ic a te th a t a weak shock propagates through and along the strand .Toe la s e r beam-path is transve rse to the s trand-ax is , v/ith a focal w id th o f 200 pm and focussed in te n s ity o f

V lG 12W/cm2. In te rferog ram s and shadowgrams, produced wiLh a 1 ns, 0.53 urn pu lse, in d ica te two d is t in c t phases in the plasma expansion. The f i r s t phase, a spherica l core o f dense plasma o r ig in a t in g from a shock propaga­t in g through the strand along the la s e r beam, expands r a d ia l ly and d r i f t s along the beam w ith a dens ity p ro­f i l e n0( t)e xp [ (r- u )2/R : ( t ) ] , where t is tim e, r is rad­ia l p o s it io n , the d r i f t v e lo c ity u v 3(10s ) cm/s, and 3R/H - 1.8 (106) cm/s. Shock compression is ve ry weak and the shock v e lo c ity is near the isotherm al sound ve­lo c i ty in the plasma [1.4(10' ) cm/s]. The second phase is approxim ate ly c y l in d r ic a l, and is produced by a shock propagating a t ^1.3 (10t ) cm/s along the strand .

WEDNESDAY, JUNE 22, 1977 LASERSROOM 129Chairman: G .I. Stegeman

9:00EE1 Tuneable Coherent Radiation in the Vacuum Ultraviolet

B.P. STOICHEFF and S. WALLACE, U vU vU U ity o i ToUOYltO

9; 45EE2 CW Raman and Brillouin Fibre Optic Lasers

D.C. JOHNSON, K.O. HILL and B.S. KAWASAKI, CommunÀCoJXOïU, R&ieatc/i Centte, O ttawa

The recent development of low-loss single-mode glass optical fiber has made possible a new class of continuous-wave lasers using stimulated Brillouin and Raman scattering as the gain mechanisms We have achieved low threshold continuous-wave oscillation by both these mechanisms using an argon-ion laser to pump long lengths of single-mode fiber. High conversion efficiencies of over 50% have been demonstrated. The Brillouin laser can be constructed in a ring-resonator configuration and a Fabry-Perot configuration. The former has potential application as a sensitive ring gyro and the latter is a potential source of picosecond pulses. The Raman laser has been demonstrated to be a tunable source in the visible and near infrared. The effect of nonlinear properties of the fiber on the Raman laser linewidth will be discussed.10: 30

EE3 Synchronization of Short High Power Laser Pulses for Plasma Interaction StudiesP.B. CORKUM, N ationa l RcAcaAck Council o& Canada

11:15A High Pressure, Continuously Tunable TE CO?

Laser.* A. W. PASTERNAK, D. J. JAMES and J. A. NILSON, Lumonics Research Ltd.— A repetitively pulsed CO2 laser operating at pressures in excess of 10 atmospheres has been developed. The discharge (1 x 1 x 50 cm3), which is UV preionized, is formed between a pair of profiled electrodes. With a stable resonator the laser delivers pulse energies of 500 mJ limited by damage to optics. When operated with a dispersive cavity the laser can be tuned continuously over ^25 cm-1 in each of the four CO2 bands with a linewidth <0.1 cm-1 and a long term frequency stability of better than 0.05 cm-1. Under these conditions pulse energies of 200 mJ are achieved without damage to the optical components. Results of a detailed study of the tuning characteristics of the laser will be presented together with data on repeti­tively pulsed operation.

* This work was sponsored by the National ResearchCouncil of Canada under the Pilot Industry/Laboratory Program.

11:30

Development of a High Power Iodine Laser.*S. ARIGA, D. FRIEDMANN and B. AHLBORN, Univ. of British Columbia»— A multistage iodine laser experiment (MILE 1) is under way. The oscillator section is now in operation. The amplifiers in modular form are under construction. Electrically excited bleachable absor­bers^ will be installed to suppress undesired couplings between two successive stages. The oscillator has two 2-ft Xenon flash lamps, a double elliptic mirror, and

dielectric mirrors for the laser cavity. The lasing medium is CF3I gas. A 20 mJ pulse of 200 nsec half­width is obtained. Output pulse has been investigated as a function of the gas pressure and the current in the flash tubes. In determining the pulse shape of the oscillator we made use of an absorption filter of continuously variable transmission to avoid saturation of the photoresistor detector. The absorbing medium of this filter is water which has an e-folding absorption length of 6.1 mm at the wavelength of the iodine laser (1.315ym).

Ishii et al., Rev. Sc. Instr. 47, 600 (1976)*Supported by the N.R.C.11:45

EEd Investigation of Tunable Stimulated Raman Scattering by Light Mixing in Liquid N2· T. SINNQTT and J~ MEYER, Univ"! of British Columbia, H. MENNICKE, Max-Planck-Institut fllr ExtraterresTische Physik, Gar- ching b. Mtínchen.-- High order tunable anti-Stokes Raman scattering is produced by mixing the radiation of a Q-switched ruby laser and that of a dye laser in liquid nitrogen. All investigated orders of both ruby laser and dye laser anti-Stokes radiation are found to have the same ruby laser power threshold of about .5MW. The intensities of the anti-Stokes radiation is found to increase linearly with ruby laser power once thres­hold has been surpassed appreciably. The dye laser anti-Stokes radiation does not exhibit a dye laser threshold power. The results can be explained by a simple theoretical model which treats the ruby laser as pump fox coherent molecular oscillations.

LIQUIDS AND STATISTICAL PHYSICS

35

V»E <E5DAY, JUNE 22, 1977 ROOM 127

Chairman: H. Slyce

9:00The Effect of Surface Curvature in Surface

Tension « * FT ET CURZÖN and R. PUDRITZ, Univ. o f Bri­tish Columbia.— It is shown that the change in sur- tace tension <5σ caused by curving a fluid surface is a function of the local mean curvature (τ) and the local gaussian curvature t q . The expression derived for 0σ is valid provided the curvatures τ and do not change appreciably over distances on the fluid surface compar­able to the range of intermolecular forces (λ). The expression derived for όσ is then used to demonstrate that curvature dependent surface energy does not change the mechanical stability of spherical droplets.

9 = 15EF2 The Effective Pair Potential in Liquid ^He.

V .F. SEARS, A.D.B. WOODS, E.C. SVENSSON, and P. MARTEL, A tom ic E n erqy o f C anada L im it e d , C h a lk R iv e r , Ont a r i o .— The iterative method proposed by Rahman1 for the direct determination of the effective pair potential, <Peff(r), in a monatomic liquid from neutron-scattering data is shown to be equivalent to solving an integral equation in which the inhomogeneous term is determined by the low-order frequency moments of the dynamic structure factor, S(Q,u), and the kernel by the pair correlation function, g(r). This equation has been solved by numer­ical iteration for liquid **He at T = 4.2 K with the help of neutron data for S(Q,ui) and X-ray results for g{r).We find that the shape of 4>eff{r) differs radically from that expected for the potential, <j){r), of an isola­ted pair by having a double minimum and being positive at large r. This unexpected behaviour is attributed to the effect of many-body interactions. We conclude that these interactions are either larger than previously estimated or else their effect on Is somehowgreatly enhanced.

* A. Rahm an, P h y s. R ev . A 1 1 , 2191 (1 9 7 5 ) .

9:30EF3 IThe Atomic Kinetic Energy in Liquid '*He.A.D.B. WOODS and V.F. SEARS, Atomic Energy of Canada Ltd., Chalk River, Ontario.— The average kinetic energy per atom, <KE>, in liquid- “He at T = l.l K and 4.2 K has been determined from analysis of neutron inelastic scat­tering measurements1 of the dynamic structure factor, S(Q,co). In the limit of large Q it can be shown that <KE> is obtained directly from <xnu one of the moments /ojn S(Q,w)dw, for n = -1 or n > 2. The analysis, which was carried out with the help of the requirement that the static structure factor (n = 0) and the f-sum rule (n = 1) be satisfied exactly, was confined to the range 60 nm“l < Q < 80 nm“l. A total of twenty-seven values of <KE> from the n = -1, 2 and 3 moments yielded 13.5 ± 1.2 K at T = l.l K and 14.1 ± 1.0 K at T = 4.2 K. While these results are in reasonable agreement with theoretical and less direct experimental estimates the change in <KF> in going from 1.1 K to 4.2 K is somewhat less than these other estimates suggest.

]R.A. Cowley and A.D.B, Woods, Can. J. Phys. 49, 177(1971).

9:1*5EFij Density Expansion of Classical Correlation Functions'.* P.MALTAIS, N.K.POPE AND S .RANGANATHAN, Royal Military College of Canada.— Using the classical grand canonical ensemble, the density expansion of the van Hove correlation function for a system of hard spheres is attempted. We have obtained expressions and numerical results upto second order in density for the total correlation function and expressions upto third order in density for the self correlation function.The expansion is carried out using the time dependent Ursell functions which in turn are expanded in terms of Yang and Lee's binary collision operators. After these transformations, the coefficient of the n3 term, for example, involves collisions between no more than 3 particles and the range of integration is only over that small part of the phase space volume that leads to col­lisions. For the 3 particle hard sphere dynamics, we

have used diagram techniques to write down the terms for sequences of two and three binary collisions. These number twenty for the third order term of self corre - lation function. Comparison with other approaches to this problem will be discussed.* Supported by DRB of Canada, Grant No. 9510-30.

10:15EF5 Hard and Soft Core Equations of State. John

STEPHENSON, llniv. of A lberta.- In order to obtain a qualitatively correct description of the second virial coefficient and the characteristic curves of a simple fluid it is necessary to take into account the solten- ing of the hard core which occurs at sufficiently high temperatures. For example, the locus of Cp extrema along isotherms which commences at the critical point and terminates on the fusion curve can be described by purely hard core equations of state, but in order to account for the occurrence of a second branch, which terminates at zero density on the temperature axis, one must consider soft core effects. There are six dis­tinct temperatures associated with the termination points of ten characteristic curves, and the Cp locus. These temperatures may be calculated from the tempera­ture dependence of the second virial coefficient. By constructing a simple soft-core model containing one characteristic temperature and an exponent, chosen to describe correctly the high temperature behaviour of the second virial coefficient, one may modify any cho­sen hard core equation of state. The complete set of characteristic curves can then be calculated, and com­pared with experimental results.

10:30Ground State Properties of Many Body Quantum

Mechanics 1 Systems in Two Dimensions. D.D. BETTS,Univ. of Alberta, and J. 0ΙΤΜΛΑ, Univ. of New South Wales.- The exact nature of the ground state of many body systems is known in only a few special cases. For the Heisenberg antiferromagnet and the XY magnet we have calculated several ground state properties exactly on square cells containing N = 8,10,16 and 18 spins.The ground state of both models is non degenerate. By extrapolation in 1/N we estimate ground state proper­ties on the infinite square lattice. For the Heisen­berg ant if erromagnet the ground state energy, E^/NJ= -0.68Ό.05 while for the XY magnet e£y/NJ = -0.5 394-0.005 . For the XY ferromagnet we also find a finite perpendic­ular magnetization in the ground state, M^"/Nm=0.67 ±0.01, but the parallel magnetization and both staggered mag­netizations tend to zero. Thus we predict a first or­der phase transition as T O in the two dimensional XY magnet. The properties of the Heisenberg antiferromag­net behave much more erratically as a function of 1/N so that precise predictions for the infinite lattice are not possible. The method can be applied to other models and other lattices.

10:^5EF7 Satisfying Frequency and Equilibrum Conditions

in Lattice Dynamics. J. W. LEECH, Univ. of Waterloo.- The problem of satisfying various equilibrum and frequency constrants in lattice dynamics is discussed.Particular reference is made to work on solid CS».

36

11:00EF8 Positive Muon Spin Depolarisation in Solids.

T. McMULLEN and E. ZAREMBA, Queen's U.— The study of the spin depolarization of polarized positive muons (μ+ ) stopped in solid targets is a recently developed technique for the study of solids. The motivation for the present work is to provide a precise interpretation of the experimental observations in terms of the micro­scopic parameters which influence uT dynamics in solids. The spin depolarization is due to fluctuations in the local magnetic field at the position of the μ+ . By introducing space-time correlation functions, the fluc­tuations due to the y+ motion in the solid can be conveniently separated from the intrinsic fluctuations arising from the dynamics of the nuclear spins. In particular, this formulation allows the effect of μ motion to be treated from a common point of view, regardless of the specific nature of this motion. Var­ious simple models of μ+ motion are examined to show what aspects of the motion are reflected in the experimental observations of spin depolarization.

WEDNESDAY, JUNE 22, 1977 ROOM 202Chairman: E .J. L lew e llyn

9 = 00EG1 Correction of Rocket and Satellite Auroral Observations for Ground Albedo.* J.S. MUKPHREE, C.D . ANGER and I.W.H. ROBERTSON, Univ. of Calgary— Rocket and satellite observations of auroral emissions may be contaminated by the effects of the earth's albedo. In particular during winter observations this effect will maximize because of the high spectra] albedo of snow cover. A straightforward albedo removal routine is used to correct emission profiles in one dimension. It is assumed that any intensity variations at right angles to these profiles have a small effect on the corrected profile. Independent input to the routine is required for the height of the emissions (approximately 100 km) and the spectral albedo (assumed to be .7 to .8 for 5577X). The effects of the correction are investigated for data taken on a rocket flown from Churchill during the winter of 1974 and from the Auroral Scanning Photo­meter on ISIS-II during the winter of 1972.

*Supported by the National Research Council of Canada.

EG2 Auroral Brightness Fluctuations in Quiet Auroral Structures.* F.T. BERKEY and N.R. PARSONS, Univ. of Calgary— It is not well recognized that quiet auroral structures (homogeneous arcs or bands) and the diffuse aurora, undergo small, but periodic fluctua­tions in their total luminosity. This phenomenon has been studied almost exclusively by Shepherd and co­workers, with the first observations reported by Iyengar and Paulson (1961). We have extended their studies using auroral imagery data from an image intensifier-television system. Our results confirm the previous observations, showing a predominant peak in the frequency spectrum having a period of 7-9 seconds. This result appears in our observations of quiet arcs at L values of 5.0, 8.8 and 16.8. Furthermore, the frequency spectra often show harmonics of the fundamen­tal frequency.

*Supported by the National Research Council of Canada.

9:30EG301d and New Concepts^ in Auroral Morphology G.G. SHEPHERD, Centre for Research in Experimental Space Science. York University.

Early concepts of the behaviour of the aurora were obtained by ground-based measurements from a few sites, that included visual observations, photography, electro­optical scanners, and radars. New perspectives have been provided by optical satellite images and it is of interest to compare these with the early measurements.

EF9 Thermo-Mechanical Coupling in Plastic Shear. T.J.T. Spanos and E. Nyland, Ι_· E.P.P. - Physics, Univ. of Alberta — In real materials such as rock deep within the earth viscositv is temperature dependent and shear heating can thus cause apparently inexplicable varia­tions in mechanical behaviour. We have exact solutions for coupled thermal and mechanical behaviour of Newtonian and non-Newtonian materials in which the exponential temperature dependence of transport properties is considered. These solutions have direct implications for the creation of macroscopic instabil­ities in materials such as rock, under verv high temperature and pressure. The onset of instability for time dependent boundary conditions is a strong function of the time history of boundary conditions.

11:15

BALFOUR W. CURRIE SYMPOSIUM - CONTRIBUTED I I

It seems that the historical selection of these sites was dominated by factors other than the aurora itself and that this critically influenced the concepts that resulted.

9 ^ 5EG4 Rocket Measurements of the Vertical Distributionof 3914A and 5577Â Emissions in Aurora.* I.W.H. ROBERTSON, C.D. ANGER and L.L. COGGER, Univ. of Calgary — A rocket-borne scanning photometer was flown into bright aurora from Churchill, February 28, 1^74 to measure the emission rates at 3914Λ and 5577A, The instrument provided numerous scans in altitude through­out the flight, both from up down and side-viewing observations. The resulting height resolution in the data was better than two km, permitting accurate height profiles to be obtained over the range 100 to 200 km.The variation of the ratio of 5577& to 3914.X with alti­tude has implications for the auroral excitation processes.

*Supported by the National Research Council of Canada.

1 0 : 0 0EG5 Optical Observations of the Davside Cleft from * 01

Cambridge Bay. Dec. 76- Jan. 77. W.A. GAULT, G.J. GOTSHALKS, R.A. KOEHLER, rTnT PETERSON, J.F. PIEAU, and G.G. SHEPHERD, York Univ. C.R.E.S.S. — Ground- based observations were made from Dec. 8 to Dec. 17, 1976 and from Jan. 1 to Jan. 8, 1977 at Cambridge Bay, N.W.T. (69.1°N, 255°E, geographic; invariant latitude 78.0°) as part of the Canadian IMS program. A four barrel photometer with an internal wavelength stepping system and an external meridian-scanning mirror was used for both periods and a Michelson interferometer was used additionally during the January campaign period. The interferometer was used in the visible wavelength region while the photometer had filters for01 6300A°, 01 5577A°, NI 5200A° and NT 4278A°. Pre­liminary analysis of the data indicates that the cleft emission was generally located equatorvard of Cambridge Bay at noon, with a defined, stable equatorward boundary. A dynamic behaviour pattern has been found for the poleward boundary with a general equatorward recession during the noon to evening transition of the observation station.

Altitude Distribution of the Diffuse Aurora Observed from ISIS-2.* L.L. COGGER and J.S. MURPHREE, Univ. of Calgary— Initial results from limb scans of the diffuse aurora as measured by the auroral scanning photometer on ISIS-2 have been obtained for the evening sector of November 9, 1972. Data were selected for con­ditions when the aurora was at the limb and subsequent spins at the same longitude showed only airglow to be present. The auroral intensity at the limb was then corrected for the airglow component, and an airglow height of 97 km was adopted as the altitude reference. Upon inversion of the corrected auroral limb scan, the height profile was found to be consistent with excita­tion by electrons of energy greater than 1 keV.

^Supported by the National Research Council of Canada.

10:30

10 : U 5Detached Arcs Observed by ISIS-2 Equatorward of

the Diffuse Auroral Belt.* M.C. MOSHUPI and C.D. ANGER, Univ. of Calgary— Detached arcs have been observed equatorward of the diffuse belt by the auroral scanning photometer on board the ISIS-2 satellite. The arcs show a strong Universal Time and longitude (corrected geomagnetic longitude) dependence, being concentrated at 270° CG longitude and at 05 UT. The highest fre­quency of occurrence is in the dusk sector in the Alaskan and Western Canadian longitude region. Statis­tically speaking, the detached arcs occur during posi­tive going Dst. The diffuseness of most of the detached arcs,(width >1° of latitude) and the intensities at 6300A (R(I6300/I3914)<0,2) suggests that the ring cur­rent ions, probably protons, may be a major cause of these arcs. The plasmapause data show that the arcs occur in the trough region. From energy estimates, it appears that protons of J(E<25 keV) = 106/(cm2 sec sr keV)0are sufficient to cause the observed luminosity at 3914A, '

*Supported by the National Research Council of Canada.

EG8 Particle Observations over Detached Arcs. D.D. WALLIS, HerzberR Inst, of Astrophysics, M.C. MOSHUPI, Univ. of Calgary, J.R. BURROWS, Herzberg Inst, of Astrophysics, and C.D. ANGER, Univ. of Calgary - Obser­vations of precipitating particles have been made on the ISIS-2 spacecraft above evening-sector detached arcs which lie equatorward of the diffuse auroral oval. The most intense arcs are characterized by enhanced pitch angle scattering of electrons of all energies (Ee < 210 keV) with peak scattering near 6 keV. Preci­pitation of protons is also observed. These events appear imbedded in a normally existing region of weak pitch angle scattering.

11:00

11:15EG9 E v id e n c e o f Io n - A c o u s t ic P ia : Waves

in R ad io A u r o r a . H AlTDOUPTS and G. J . SOF KO .I . S . A . S . . U n iv . o f S a s k a tc h e w a n , S a s ka to o n — The e x is t e n c e o f io n - a c o u s t ic p lasm a waves in r a d io a u ro ra i s in v e s t ig a t e d by means o f a VHF b i s t a t i c r a d io D o p p le r s y s te m . E x p e r im e n ta l r e s u l t s o b ta in e d by u s in g b o th t im e and f r e ­quency dom ain te c h n iq u e s a re found to ag re e w it h th e m ain p r e d ic t io n s o f tw o - s tre a m i n ­s t a b i l i t y t h e o r y . A ve rag ed pow er s p e c t ra i n ­

d ic a te t h a t o c c a s io n a l l y , f o r s h o r t p e r io d s o f

t im e , a n a rro w s t ro n q peak d o m in a te s th e s p e c tru m and t h a t i r r e g u l a r i t i e s move s o u th ­

w ards n e a r th e io n - a c o u s t ic speed in th e medium . The p o s i t io n o f th e peak is fo und to be unchanged f o r d i f f e r e n t o b s e r v a t io n t im e s and a z im u th a n g le s . D e m o d u la t io n a n a ly s is in d ic a t e s t h a t io n - a c o u s t ic ty p e s p e c t ra a re a s s o c ia te d w i t h s p a t i a l l y lo c a l i z e d s t ro n g

s c a t t e r e r s whose e x is te n c e ap p ea rs to be de­p en d en t on c e r t a n t h r e s h o ld c o n d i t io n s .G round m agne tog ram s s u g g e s t sudden c u r r e n t i n ­

t e n s i f i c a t i o n s d u r in g th e t im e th e io n a c o u s t ic echoes a re o b s e rve d

WEDNESDAY, JUNE 22, 1977 ROOM 107

14:00F Annual General Meeting of the Canadian Association of Physicists

Chairman: R.J.A, LEVESQUE

WEDNESDAY EVENING

Reception and Banquet

18:45 Reception: Marquis Hall, Hosted by the University of Saskatchewan

19:30 Banquet

38

THURSDAY, ROOM 107 Chairman:

JUNE 23, 1977 PLENARY SESSION

H.E. Johns

9:30S k i Electron Microscopy - Imaging of Atoms, Molecules and Cells

P. OTTENSMEYER, Ontario Cancer In s titu te , and U n ive rs ity o|j Toronto

Electron microscopy is one of the physicists most direct approaches to the visual­ization of man's microcosm. With a resolution capability of between 2 to 5A, depending on the instrument, the microscope has made imaging of atomic lattices, crystal planes, ordering in metal alloys, dislocations and other defects a routine matter in solid state physics and metallurgy. In spite of these capabilities, the application of this instrument to biological problems invariably resulted in images displaying a useful resolution of 20 to 5θΧ. The problem here is three-fold: lack of contrast due to the rather feeble scattering of electrons by light atoms, severe chromatic aberration due to predominantly inelastic scatter by light atoms, and finally radiation damage to the rather fragile biological specimen. Our partial though rather successful solution has been dark field microscopy to obtain contrast, an imaging energy selecting microscope to eliminate chromatic aberration, and signal averaging of noisy images to reduce the electron dose and consequently the damage required for imaging. The techniques have permitted imaging of individual atoms, and the three-dimensional structure determination of several small proteins, a result hitherto only possible by X-ray diffraction, while the energy selecting capability will provide a new analytical capability in cytochemistry, histology, pathology, as well as of course in physics and material science applications.

10:20 Break

10: AO GA2 Observing the Dayside Magnetospheric Cleft

G.G. s h e p h e r d, Vork U n ive rs ity

The magnetosphere cleft denotes a region of neutral magnetic field lines on the earth's dayside where solar wind plasma penetrates the earth's magnetic field, and reaches to ionospheric levels. The locus of its ionospheric projection in the northern hemisphere is accessible only from Canada and Greenland. Although the ionospheric responses are pronounced they were not detected until recently because the "bottomside" ionospheric responses can be masked by other effects. However, the "topside" effects are readily observed with a topside sounder and by many other detectors on the ISIS satellites. Experience gained from these satellites led to the establishment of an expeditionary sounding rocket launch site at Cape Parry, NWT, and to a number of successful launches as well as extensive ground-based measurements. One useful ground observable aspect of the cleft plasma is atomic oxygen 6300A emission. If the human eye had its peak response in the red, the magnetosphere cle!t would have become known in Canada through early Arctic explorations.

11: 30 GA3 New Developments in Intermediate Energy Physics

d . m e a s d a y. U niversity 0(j B ritish Columbia

Some experiments at the meson factories have now been completed and we are beginning to reap the fruits of over ten years of labour. Emphasis in the talk will be given to recent results of experiments at TRIUMF on the nucleon-nucleon Interaction, on nuclear studies and on the elusive decay u -►e y. A short presentation will also be given of the chemistry and solid-state physics which has been studied with polarized mouns (pSR).

THURSDAY, JUNE 23, 1977 MARQUIS HALL

13:00 CAP COUNCIL

Chairman: H.E. Johns

AUTHOR INDEX/INDEX DES AUTEURS

Ahlborn, B., ADI,8; EDI; EE5 Albrecht, G., DD1 Alcock, A.J . , ED9 Aldrich, J.E., DCA Alexander, T.K., BD7 Andrew, J.W., CD3,4 Anger, C.D., EG1,4,7,8 Ansaldo, E.J., DB3 Ariga, S., EE5 Arimondo, E., CB7 Armstrong, B., ADI Armstrong, R.L., BEIArsenault, H. , AE2Azuma, R.E., , BD 6

Bacon, M.E., , AD10Baird, D.C. , CGIBall, G.C., BD7 Barnard, A.J., AD10 Basinski, S.L. , DG5 Bavaria, G.K. , BFA Beaudet, G., AA2 Beaudry, G., DD12 Beckmann, P.A., CB3 Bedford, R.E., DG3 Beer, G.A., BD1,2 Bergersen, B., CG8; EBI Berka, 1., BD6 Berkey, F.T., EG2 Berry, H.C., DF3 Betts, D.D., EF6 Bird, L., BF5 Birnie, H.H., DI2 Blaauw, C., DG8 Bonbright, D.I., BD3 Bonner, R.F., ED7 Boucher, C., AD3 Brodie, D.E., BB2,3 Brooks, R.L., DF7 Brown, A., BFl Brown, W.R., CD6 Brunei, F., AD6 Bryman, D.A. , BD1,2 Burgess , A .E., CD5 Burke, D.G ., CF8 Burnett, N.Η., CAA Burrows, J.R., EG8 Buyers, W.J.L., BEI

Caille, A . , DG10 Calaprice, F.P., DAI Campbell, E.M.C., DC5 Capiack, C.E., AD9; DD10 Carbno , C.C., EC5 Carette, J.-D., ABA Carlson, R.F., BD8 Carter , A .L., BC1 Cervenan, M.R., DDA.5 Chandraiah, G. CEA Chartier, D., DG2 Cheeke, D., EBA Chen, T ., AD2 Chiu, J.C.H., CG2 Choudhury, F.N., CF1 Clough, S., CB3 Code, R.F., CB2 Coev, J.M.D., AC3 Cogger, L.L., DE6; EGA, 6 Collins, M.F., AC4 Conkie, W.R., BF7 Corkum, P.B., EE3 Costain, C.C ., DFl Cox, A.J., BD8 Crawford, J.E., BFA Curzon, F.L., AD10; EF1

Daams, Η. , DFlDaigle,■ G .A. , DE9Das Gup)ta, S. , CFIDatars,, w .R. , DG 2Davies,, w.G. , BD7Dawson.► D.J. , CD7DeMille, G.R., CD2 Deslauriers, J., CF5 Dixit, M.S. , BD1,2 Donnelly, K.E., DF6,7 Douglas, A.E., AB1

Douglas, R.J., DG5 Drouet, M.G., AD7; DD2,3 Durocher, G., DF2 Duwury, C., BB8 Eastman, P.C., BB2 English, P.S. , BE3 Enright, G.D., ED5 Evans, H.C., BD3 Ewan, G,T., BD5

Fabian, J., BE7; CG9 Faulkner, J.H., BG1 Fawcett, E., DG1 Ferdinande, H.M., CF9 Findlay, R.G. , BF5 Fletcher, R., DG4 Fong, K., EDI Forster, J.S., BD7; DA3 Forsyth, P.A. , BAA Fowler, W.A., AA1 Fraser, J.S., CC2 Friedmann, D., EE5 Fuchs, V.f DD12 Fuj ii, Η., AE3 Fulford, J.E., ED7

Gabrielse, G., DF3 Gault, W.A., EG5 Gaunt, P., DG9 Gerig, L.H., CD7 Ghaem-Maghami, V., CE3 Ghosh, S.K., DC3 Gillespie, R., DG2 Glorieux, P., CB7 Glyde, H.R., BE5 Goodchild, G., CBA Gordon, J., DC7 Gordon, L.A., DG5 Gotshalks, G.J. , EG5 Graham, W.R.M., CE6 Green, P.W., CFA Gregory, B.C., CA2 Gregory, J.B., DE10 Grek, B., ED3 Grundke, E.W., BE2 Grynszpan, R., CG6

Haldoupis, C., EG9 Halverson, W., DD6 Hansen, J.-P., BE3 Harris-Lowe, R.F., DB2 Hasell, D.K., BD8 Herring, R.W., DE8 Higinbotham, J., CB2 Hill, K.O., EE2 Hirose, A ., ADA Hollinger, A., CE5 Holloway, A.F., DC5 Holroyd, F.W., DG1 Hooper, H.R., CFA Houtman, Η., DDl Huang, H., CF3 Humphrey, K., CD5 Hunten, D.M., BA1 Hunter, D.L., BE3

Isenor, N.R., DD9; EDA,5

Jaanimagi, P., EDAJackman, T.E., BE7; CG9,10Jackson, K.P., BD6James, C.R., DD10James, D.J., EEAJeremie, H., BD4Jericho, M.H., BE9Johns, J.W.C., CB5Johns, M.W., CF2,6,7; DllJohnson, D.C., EE2Johnson, R.R., DAAJohnston, T.W., DD7,8,11; ED3Jones, A.V., BA2Jones, L.A ., AD11Joshi, Y.N., AB2; DF5Jovanovich, J.V. , BF6Judah, J., DG8

Kallne, E., AD11 Kamal, A.N., BCA Kang, C.S., DG6 Karmendy, C.V., DD6 Kawasaki, B.S., EE2 Kawasaki, K., DE2 Keith, V., BB5; CGA Kelly, F.M., AB3 Kennedy, G,, BDA Kenway, D.J., BB8 Kernahan, J.A., DF6 Khaneja, R., DE6 Khanna, F.C., DB1; EA2 Kiang, D., ECA Kieffer, P., AD7 Kieser, W.E., BD6 Kim, J.S., BA3 Kim, S.K., BD1 Kirczenow, G., BB7 Klein, M.L. BE5 Koehler, R.A., EG5 Kovács, G.J., BB6 Kulkarni, N., CD9 Kwan, J., EDI

Lam, H.-L., DEI Lamarche, J.L.G,, CBA Larlee, K., CD2 Lee, J.K.P., CF3 Leech, J.W., EF7 Lees, R.M., CB6 Leiper, W., DG8 Lemay, L., BDA Leo, W.R., BF2 Lepine, Y., DG10 Leslie, J.D., BB5; CG3,4 Lew, H., CE6 Lim, C.S., CG3 Lim, P.K., BB2,3 Lit, J.W.Y., AE3 Litherland, A.E., EA1 Little, M.S., DC2 Liu, C.F., DFA Livesey, D.L., CD2 Livingston, A.E., DF3 Llewellyn, E.J., DE7 Lokan, K.H., CF9 Long, B., CD9 Loter, N.G., DD6 Lyon, G.F., DEA

Ma, W.W., DD6 MacArthur, D.J., BD5 MacDonald, J.A., BD1,2 MacDonald, J.C.F., CD7 MacDonald, J.R., BE7; CG9 MacDonald, W.J., EA3 Mach, H., CF2 MacKay, G.R., DG8 MacKenzie, I.K., BE7; CG9,10 Mah, S.Q., AD3 Mailer, K., CD2 Mak, H.B., BD5,6 Malm, H.L., BFl Maltais, P., EF4 Manson, A.H., DE10 March, R.E., ED7 Margaziotis, D.J., BD8Mark, S.K., CF5Martel, P., EF2Martin, F., ED 3Mason, G.R. , BD1Matz, D., BEA May, A.D., CE3 McDonald, A.B., BD6 McDonald, W.J., CFA McKee, B.T.A., CG6,7 McKee, J.S.C., BD3; DF2 McKellar, A.R.W., CB5 McLatchie, W., BD6 McMullen, T., CG8; EF8 McMullin, J.N., AD9 Measdav, D., GA3 Mennicke, H., EE6 Meyer, J., DDl; EE6 Millar, T.W., BF6 Milrov, R.D., DD10

uo

Mintz, D., BEI Molson, L.D., CD6 Moore, R.A., DF4 ; DG7 Moore, R.B., BF2,4 Morawit z, Η., EB3 Morrison, R.W., DD6 Moshupi, M.C., EG7,8 Muir, W.B., BE8 Mukherjee, B.K,, CGI Mungall, A.G. , DFl Murphree, J.S., EG1,6 Mylvaganam, C.K., DG9

Nasr, T.N., BD8 Neilson, G.C., CF4 Nester, J.M., EC5,6 Neufeld, C.R., ED8 Ng, A.K.H., DD4 Ng, J.N*, BC3 Nguyen, D.L., DD7,8 Niewaga, A ., EC4 Nilson, J.A., EE4 Noel, P., ED8 Nyland, E., EF9

O'Connell, Μ., CB4Offenberger, A.A., CA3; DD4,5Oh, S., BF3Oitmaa, J., EF6Oka, T., CB7Olin, A., BDl,2Olson, J.V., DE2O'Neill, J.A., DF8Ormrod, J.Η. , CC3Ottensmeyer, F.P., CAl; CD3,4

Panar, J.D., CF8 Parbhakar, K.J., DD7,8 Parsons, N.R., EG2 Parsons, R.R., BB7 Pasternak, A.W., EE4 Patera, G. , EC2 Pathak, B.P., CF3 Pearce, R.M., BDl,2 Pearson, J.M., DA2 Peemoeller, H., CD1 Pepin, H., ED3 Perz, J.M., AC2; DG1 Peterson, R.N., EG5 Pieau, J.F., EG5 Pinnington, E.H., DF6,7 Pintar, M.M., CB1; CD1 Plumer, M., DG12 Pocobelli, G., AD5 Poffenberger, P., BD2 Pogson, R., BF3

Pomroy, C., CD10 Pope, N. K. , EF4 Poutissou, J.-M., BC2 Powell, B.M., BEI Pudritz, R., EF1

Rabin, E., DC6 Ramsay, D., DF2 Ranganathan, S., EF4 Read, L .A.A., AE5 Reesor, G.E., AE5 Rehfield, D.M,, BD9 Repacholi, M.H., DC3 Rheault, F., ED3 Richardson, M.C., ED4,5 Riggin, M., CB5 Robert, A., ED8 Robertson, B.C., BFl Robertson, E.W,, DI4 Robertson, l.W.H., EGl,4 Robinson, A.M., CE7; ED6 Roger, W.A., BE9; DG11 Ross, C.K., CF9 Rostoker, G., DEI,2 Roy, M ., AD7

Saimoto, S., CG7 Saint-Hilaire, G., ED2.8 Samson, J.C., DE3; ED9 Sancton, R., BF5 Santiago, J., ED6 Scholz, G.A., DG2 Schott, L., AD2 Schreiner, L.J., CD1 Schultz, P.J., BE7; CG9 Scott, G.D., BB4,6 Sears, V.F., EF2.3 Servranckx, R., CCI Sharma, P.D., CD8 Shepherd, G.G., EG3,5; GA2 Shepherd, J.J., BG2 Sherman, N.K., CF9 Shiah, R., BB2 Shuter, W.L.H., AA4 Siefken, H.E., CF4 Simpson, A.M., BE9; DG11 Singhall, N.C., CF6,7 Sinnott, T., EE6 Skinner, R., EC5 Smyth, D.L., CD6 So, C.B., DG7 So , V., AE4 Sofko, G.J., EG9 Sourkes, A.M., BD8 Spanos, T.J.T., EF9

Srivastava, R.P., DF3 Stegeman, G.X., AE4 Steinitz, M.O., DG12 Stephenson, J., EF5 Stevens, J.R., CG10; D13 Stewart, A.T., CG6,7; DG5 Stinson, M.R., DG4 Stoicheff, B.P., DB4; EE1 Stott, M.J., BE6 Stryland, J.C., CE2 Sutherland, P., AA3 Suzuki, M., AC1 Svensson, E.C., EF2 Sykes, D.H., DC1 Szegedi, L., DC7 Szili, Z., ED2

Teichmann, J., AD3,6; CAl Thewalt, M.L.W., BB7 Thompson, J,, CF2,6,7 Tindall, D.A ., DG12 Tod , A., DC7 Townsend, M.G., BE8 Truong, V.V., BB4

Van Andel, H.W.H., AD3 Vanderkooy, J., DG6 van Driel, Η., AE1 Vankleef, Th.A.M., DF5 Villeneuve, D.M., ED5 Vincent, J.S., BDl

Wadati, Μ., EC3 Walker, Μ., EC1 Wallace, S., EE1 Wallis, D.D., EG8 Wang, S., DG7 Watson, J.W., BD3 Watts, J.H., DD6 Welchman, F.L., BB8 Weiler, L., EB2 Welsh, H.L., CEI,5 Westfall, G.D., EA4 Wiederick, H.D., CGI Wilk, S.F.J., DF2 Wong , Μ., AE5 Wood, B.M., CB2 Wood, G.H., CG5 Woods, A.D.B., EF2,3

Yan, K.L., CE2

Zaremba, E., BB1; BE6; EF8 Ziauddin, S., DE5 Zuk, W.M., DC3,6,7

Crystallographyat

McGill UniversityPost doctoral position, open June 1st, 1977.

Candidate must have rigorous scientific training: BS in Physics, MS in Applied Physics, PhD in Materials Science from a leading Institute of Technology, with usual academic honours. His (her) previous research must have dealt with crystalline materials:

Particularly required are: skillls at growing crystals of high purity and low imperfection den­sity, at preparing samples for X-ray study, at computer programming and electronics, as well as considerable experience in machine shop work. Reading knowledge of German and some familiarity with French, essential, although the Crystallographic Laboratory operates in English. Interest in research-teaching career, a plus.

Applicants should write to

Professor G. Donnay Department of Geological Sciences McGILL UNIVERSITY 3450 University Street Montreal, PQ, Canada H3A 2A7

Royal Military College

of CanadaDEPARTMENT OF PHYSICS

Candidates are required for positions in the Department of Physics to teach in French to undergraduate students. A Ph.D. in Physics is required, preferably with experience in the field of low temperature or solid state physics. Salary and rank will depend upon qualifications. Candidates should send a curriculum vitae and the names of three referees to:

D. C. BairdChairman, Department of Physics Royal Military College Kingston, Ontario K7L 2W3

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TRIUMFSimon Fraser University

A JUNIOR RESEARCH SCIENTIST — NUCLEAR CHEMISTRY

A Junior Research Scientist position is available, subject to final funding approval, start­ing April 1st., 1977, in Experimental Nuclear Chemistry or Physics at the TRIUMF 500 MeV Cyclotron. Canadian citizenship or landed im­migrant status and compliance with atomic workers regulations are cond itions of employement.

The successful applicant will be engaged in the Simon Fraser University research program at the Cyclotron which includes studies in in­termediate energy fission and fragment emis­sion reactions and in nuclear spectroscopic studies of nuclei far from stability.

Salary will be commensurate with experience.Send curriculum vitae, list of publications and

names of referees to:

Dr. R. G. Korteljng Department of Chemistry Simon Fraser University Burnaby, B.C. V5A 1S6

University of Saskatchewan

PHYSICS DEPARTMENT

A position of Assistant or Associate

Professor of Physics may be available in the near future. Applicants with a Ph.D. and with extensive research experience in Plasma Physics will be given preference.

Other areas of interest to the Physics Department are Nuclear Physics, Upper

Atmospheric Physics and General

Relativity.

Applications and curricula vitae should be sent, prior to June 15, 1977, to:

HeadDepartment of PhysicsUniversity of SaskatchewanSaskatoon, SaskatchewanS7N 0W0

Département de physique

POSTE DE PROFESSEUR EN ASTRONOMIE OPTIQUE

Un poste de professeur est maintenant dis­ponible au Département de physique de l’Université de Montréal. Le candidat devra accepter de participer à la mise au point de l’équipement scientifique d’un nouvel obser­vatoire astronomique dont l’instrument principal sera un télescope d’environ 1,5 m d’ouverture. Il contribuera aussi aux program m es de recherche et d’enseignement du Département.

L'engagement pourra se faire dàs l’été 1977. Le rang académique (adjoint, agrégé ou titulaire) et le traitement sont en raison des qualifications et de l’expérience.

Les personnes intéressées sont priées de faire parvenir leur curriculum vitae, les noms de deux répondants et toute autre documentation, à l’adresse suivante:

Le DirecteurDépartement de physique Université de Montréal C.P. 6128 Montréal, Québec H3C 3J7

Queen’sUniversity

POSTDOCTORAL FELLOWSHIPSThe Department of Physics invites

applications for postdoctoral fellowships

from physicists whose interests lie in the areas of:

Nuclear Physics,Radio Astronomy and Astrophysics,Solid State and Low Temperature

Physics,Theoretical Physics

A part-time lectureship on a non­permanent basis may become available in Astronomy and Astrophysics.

For further information please write (with curriculum vitae) to:

Dr. G. T. Ewan Head, Department of Physics Queen’s University Kingston, Ontario

Ontario Cancer FoundationLONDON CLINIC

DIVISION OF NUCLEAR MEDICINE

Applications are invited for a position for a physicist with experience in Nuclear Medicine, preferrably with a graduate degree. Areas of responsibili­ty include instrumentation, radiation safety, computer operation, teaching and research. Successful applicant will be nominated for University ap­pointment. Salary commensurate with qualifications and experience.

Send cu r r icu lum vitse, list of publications, names of references to:

Dr. T. A. Watson, DirectorOntario Cancer Foundation, London ClinicVictoria HospitalLONDON, OntarioN6A 4G5

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National Research Conseil national Council Canada de recherches Canada

PHYSICISTThe Acoustics Section of the Division of

Physics requires a physicist to conduct research in a group working in several areas of basic and applied acoustics.

The applicant should have a recent Ph D. degree in physics, or a related discipline rele­vant to acoustics, with a demonstrated ability to elucidate fundamental mechanisms by experimental and/or theoretical research. For­mal training in acoustics is desirable, though a knowledge of classical wave motion or of fluid mechanics would be a useful substitute. Ver­satility, ingenuity and adaptability are essen­tial.

Language Requirements: Knowledge of either the English or French language is required for this position.

Salary: Up to $21,550 per annum, depend­ing on qualifications.

Apply in writing giving complete details of education and experience to the Employment Officer National Research Council of Canada Ottawa, Ontario, K1A 0R6 In reply please quote P-77-1048.

PHYSICIENLa Section de l’acoustique de la Division de

physique a besoin d'un physicien pour raire de la recherche au sein d'un groupe travaillant à plusieurs aspects de l'acoustique fondamen­tale et appliquée.

Les personnes intéressées devraient posséder un doctorat récent en physique, ou dans une d isc ip line connexe reliée à l'acoustique, ainsi qu'une aptitude à élucider des mécanismes fondamentaux par la recherche expérimentale et/ou théorique. Il est désirable d'avoir reçu une formation en acoustique, mais une connaissance du mouvement classique des ondes ou de la mécanique des fluides serait un substitut utile. Il est essentiel de pouvoir travailler dans plusieurs domaines, d'être ingénieux et de pouvoir s'adapter facilement.

Exigences Linguistiques: La connaissance de la langue française ou de la langue anglaise est requise pour ce poste.

Traitement: jusqu’à $21550 par année, selon la formation et l'expérience.

Prière d'adresser un curriculum complet à l'Agent d'emploi Conseil national de recherches

du CanadaOttawa, Ontario, K1A 0R6Veuillez donner la référence P-77-1048.

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1Reflectance Spectrum of 20D10BD.1 Mirror

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