Physics in

The Bulletin of
The Canadian Association
of Physicists
Physics in
Vol.34 No. 2
C o n g r e s s Issue 1978
Bulletin de
l'Association canadienne
des physiciens
Vol. 34 N ° 2
N u m é r o du C o n g r è s 1978
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Physics in
Canada
The Bulletin of
The Canadian Association
of Physicists
Vol. 34 N o . 2
Congress Issue 1978
Bulletin de
l'Association canadienne
des physiciens
Vol.34 N° 2
N u m é r o du C o n g r è s 1978
EDITORIAL B O A R D / C O M I T É DE RÉDACTION
La Physique
au Canada
Rédacteur en c h e f / E d i t o r
E. R. Fortin
Dépt. de Physique, Université d ' O t t a w a (613) 231-5803
1978 C A P Congress, G e n e r a l I n f o r m a t i o n
i
Associate E d i t o r / R é d a c t e u r Associé
C o n g r è s 1978, renseignements généraux
i
M a p / P l a n du C a m p u s
v
M , L. J e n to
Managing/Administration
Advertising E d i t o r / R é d a c t e u r à la publicité
C A P Medallists 1 9 7 8 / L a u r é a t s de l ' A C P 1978
vi
C A P Prize Exam 1 9 7 8 / E x a m e n de l ' A C P 1978
vi
R. C. S m i t h
Future Congresses/Congrès futurs
vi
Laboratoires G o u v e r n e m e n t a u x / G o v e r n m e n t Labs.
Instructions for T i m e d Papers
W . Coderre
Book Review E d i t o r / R é d a c t e u r à la critique des livres
vii
J. Rolfe
Invited S p e a k e r s / C o n f é r e n c i e r s invités
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Physics D i v . , N R C , Bldg. M - 3 6 , M o n t r e a l R d „ O t t a w a (613) 993-2046
Exhibitors/Exposants
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x
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C o m m u n i t y Colleges/Collèges C o m m u n a u t a i r e s
P . E. Kelly
A l g o n q u i n College, 200 Lees Ave., Ottawa (613) 237-8142
Affaires Étudiantes/Student Affairs
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. A.o fDPhysics,
a i g l e Carleton University, O t t a w a (613) 993-2840
Dept.
A u t h o r I n d e x / I n d e x des a u t e u r s
Rédacteurs R é g i o n a u x / R é g i o n a l Editors
Western Canada/Ouest Canadien :
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Dept. o f Physics, University o f A l b e r t a , E d m o n t o n (403)432-4127
A t l a n t i c Provinces/Provinces de l ' A t l a n t i q u e :
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A D V E R T I S I N G , SUBSCRIPTIONS, C H A N G E OF ADDRESS
PUBLICITÉ,
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Phone: (613) 237-3392
® Canadian Association of Physicists//'Association
canadienne des physiciens 1978. All rights reserved
51
OFFICERS OF THE ASSOCIATION/BUREAU DE DIRECTION
C0UNCIL/C0NSEIL:
1977-78
*President
*Past President
*Vice-President
*Vice-President Elect
*Honorary Secretary-Treasurer
Director - Members
Director - Affiliates
Director - Student Members
Director - Corporate Members
H.E. Johns
,J.A. Lévesque
,R. Haering
, A. FOrsyth
,G. McNamara
, Lysons
,K. Walker
, Mizrahi
,H. Ungar
Ontario Cancer Institute
Université de Montreal
University of British Columbia
University of Western Ontario
National Research Council, Ottawa
National Research Council, Ottawa
Energy Mines & Resources, Ottawa
University of Toronto
Radionics Limited, Montreal
G. Rostoker
F.M. Kelly
D.W. Strangwav
W.J.L. Buyers
M.H. Repacholl
W. Falk
J.W.Y. Lit
J. Hébert
P.W. Whippey
C. Richard
B. Goulard
University of Alberta
University of Manitoba
University of Toronto
Atomic Energy of Canada Limited
Radiation Protection Bureau
University of Manitoba
Wilfrid Laurier University
Université d'Ottawa
University of Western Ontario
Institut de Recherche de 1'Hydro-Québec
Université de Montréal
DIVISION CHAIRMEN
Aeronomy & Space Physics
Atomic & Molecular Physics
Canadian Geophysical Union
Condensed Matter Physics
Medical & Biological Physics
Nuclear Physics
Optical Physics
Particle Physics
Physics Education
Plasma Physics
Theoretical Physics
C0UNCILL0RS/C0NSEILLERS
British Columbia and Yukon
D.E. Lobb
M. Plischke
(1)
(2)
University of Victoria
Simon Fraser University
Alberta
H.R. Krouse
F.L. Weichman
(1)
(2)
University of Calgary
University of Alberta
Saskatchewan and Manitoba
J.S.C. McKee
J.F. Kos
(1)
(2)
University of Manitoba
University of Regina
Ontario - Southwest
M. Fujimoto
E. Habib
(1)
(2)
University of Guelph
University of Windsor
Ontario - Central and North
E.D. Hallman
F. Code
(1)
(2)
Laurentian University
University of Toronto
Ontario - East
M.K. Sundaresan
M. Sayer
(1)
(2)
Carleton University
Queen's University
Ouébec
Benoit Jean
M. Fortin
(1)
(2)
INRS, Université de Ouébec
Université du Ouébec à Chicoutimi
New Brunswick and Newfoundland
R.M. Lees
H. Kiefte
(1)
(2)
University of New Brunswick
Memorial University of Newfoundland
Nova Scotia and P.E.I.
A.M. Simpson
D. Pink
(1)
(2)
Dalhousie University
St. Francis Xavier University
At large
J.H. Ormrod
M.G. Drouet
(1)
(2)
EDITOR - CANADIAN JOURNAL OF PHYSICS
P.R. Wallace
Chalk River Nuclear Laboratories
Institut de Recherches de 1'Hydro-Québec
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 1978; (2) Term ends June 1979
CORPORATE MEMBERS - 1978
MEMBRES CORPORATIFS - 1978
ALLAN CRAWFORD ASSOCIATES LIMITED
GULF OIL CANADA LIMITED
APTEC ENGINEERING LIMITED
INSTITUT DE RECHERCHES DE L'HYDRO-QUEBEC
UNIROYAL LIMITED
BARRINGER RESEARCH LIMITED
LEIGH INSTRUMENTS LIMITED
VARIAN ASSOCIATES OF CANADA LIMITED
SPAR AEROSPACE PRODUCTS LIMITED
BELL-NORTHERN RESEARCH LIMITED
LINEAR TECHNOLOGY INCORPORATED
CTF SYSTEMS INCORPORATED
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CANADIAN GENERAL ELECTRIC COMPANY LIMITED
MACDONALD DETTWILER & ASSOCIATES LIMITED
MCGILL UNIVERSITY
COMPUTING DEVICES COMPANY
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MEMORIAL UNIVERSITY OF NEWFOUNDLAND
DATACOMP ELECTRONICS LIMITED
ONTARIO HYDRO
UNIVERSITY OF OTTAWA
EALING SCIENTIFIC LIMITED
POLYSAR LIMITED
UNIVERSITY OF SASKATCHEWAN
EDWARDS HIGH VACUUM (CANADA) LIMITED
RADIONICS LIMITED
UNIVERSITY OF VICTORIA
ELECTROVERT LIMITED
SED SYSTEMS LIMITED
UNIVERSITY OF WATERLOO
i
RENSEIGNEMENTS GENERAUX
GENERAL INFORMATION
A l'occasion de son Centenaire, l'Université de
Western Ontario est heureuse d'accueillir le
33ème Congrès annuel de l'Association canadienne
des physiciens, du lundi 12 juin au jeudi 15
juin 1978. La réunion estivale de l'American
Association of Physics Teachers aura également
lieu à l'Université de Western Ontario du
mercredi 14 juin au vendredi 16 juin et certaines
sessions (éducation à la physique) auront lieu
conjointement.
In 1978, as part of its centennial celebrations,
the University of Western Ontario is pleased to
host the thirty-third annual Congress of the
Canadian Association of Physicists from Monday
June 12th to Thursday June 15th. The Summer
Meeting of the American Association of Physics
Teachers will also be held on campus from
Wednesday June 14th to Friday June 16th and some
sessions, e.g. on Physics Education, will be
scheduled jointly.
ARRIVEE
ARRIVAL
L'Université de Western Ontario est située sur
un terrain de 300 acres longeant la côte nord de
la rivière Thames, à environ 3 milles au nord du
centre-ville et à peu près 6 milles à l'ouest de
l'aéroport de London. La meilleure façon de vous
rendre de l'aéroport à l'Université est de prendre
un taxi (environ $8.50) mais il y aura également
un service de limousine de l'aéroport jusqu'au
campus et jusqu'au Holiday Inn du centre-ville
($3.00 par personne). Si vous arrivez à la gare
de trains ou d'autobus, vous pouvez facilement
vous rendre à l'Université en prenant l'autobus
no. 6. Ceux qui arrivent en voiture sont priés
de noter que la cité universitaire est située
dans le secteur nord de la ville, juste au sud
du croisement des routes 4 et 22. Si vous
arrivez par la 401, prenez la sortie 19 ou 20 et
dirigez vous vers le nord sur la route 4 ou sur
le chemin Wellington et la rue Richmond. Les
délégués qui ont réservé une chambre à la
résidence universitaire devront se rendre
directement au Pavillon Saugeen-Maitland s'ils
arrivent le dimanche 11 juin, ou au Centre des
sciences sociales s'ils arrivent plus tard (cf,
plan du campus). En cas de difficultés, veuillez
contacter le comité local au 519-679-2289.
The University of Western Ontario is located on
a 300 acre site spanning the north branch of the
Thames River some three miles north of the City
centre and approximately 6 miles west of London
airport. The most convenient means of transportation from the airport to the campus is via
taxi (fare about $8.50), however, limousine
service will also be available from the airport
to the campus and to the City Centre Holiday Inn
at a charge of $3.00 per person. From the railway and bus stations in downtown London the
campus is readily accessible via the #6 Richmond
bus route. Delegates travelling by car should
note that the campus is on the north side of the
city just below the intersection of highways 4
and 22. Those approaching via highway 401 should
exit at interchange 19 or 20 and travel north on
highway 4 or Wellington Road/Richmond Street
respectively. Delegates with reservations for
on-campus accommodation should proceed directly
to Saugeen-Maitland Hall if arriving on Sunday
June 11th, and to the registration desk in the
Social Science Centre if arriving after Sunday
(see campus map). In case of difficulties the
Local Committee may be contacted at (519)
679-2289.
STATIONNEMENT
PARKING
Les délégués en résidence auront accès au terrain
de stationnement adjacent au Pavillon Saugeen
Maitland; tarif 25ç par entrée, ou $1.00 pour la
durée du congrès. Vous pourrez prendre les
dispositions nécessaires lors de votre arrivée
à la résidence. Les délégués qui résident
ailleurs auront le choix entre 2 stationnements
(Medway et Saugeen-Maitland); tarif 25ç par entrée.
Parking facilities for delegates residing on
campus will be available immediately adjacent to
Saugeen-Maitland Hall at a cost of 25c per entry
or $1.00 for unlimited entry for the duration of
the Congress. Arrangements can be made upon
arrival at the residence. Delegates living offcampus may use one of two parking lots (Medway
and Saugeen-Maitland) at 25ç per entry.
INSCRIPTION
REGISTRATION
L'inscription au Congrès aura lieu entre 16h et
22h dans le foyer du Pavillon Saugeen-Maitland
le dimanche 11 juin, puis au 3036 du Centre des
sciences sociales, lieu du congrès, par la suite.
Les frais d'inscription sont les suivants:
Registration will be held from 4:00 - 10:00 p.m.
in the foyer of Saugeen-Maitland Hall on Sunday
June 11th and thereafter in room 3036 of the
Social Science Centre where the congress sessions
will be held. The schedule of registration fees
is as follows:
Membres de l'ACP
Non-membres
Enseignants du secondaire et
étudiants sous-gradués
$35.00
$45. 00
$ 5.00
Les invités des délégués sont priés de s'inscrire,
sans frais; les billets pour le banquet de l'ACP,
les activités mondaines et les excursions seront
en vente au bureau d'inscription.
CAP Members
Non-members
High school teachers and undergraduate students
$35.00
$45. 00
$ 5.00
Guests accompanying delegates are requested to
register without fee. Tickets for the CAP banquet,
various social events and tours will be available
at the registration desk.
11
REPAS
MEALS
Les délégués en résidence au Pavillon SaugeenMaitland pourront prendre leur petit déjeuner
entre 7hl5 et 9hl5 et ce repas est compris dans
le prix de la pension. Autrement, on pourra
manger à différents endroits sur le campus:
Delegates staying at Saugeen-Maitland Hall will
be served breakfast from 7:15-9:15 a.m. as part
of their accommodation package. Otherwise meals
will be available in various on-campus locations
as follows:
Petit déjeuner:
Breakfast:
Cafétéria "Centre Spot", Centre communautaire
universitaire, à partir de 7h30.
"Centre Spot" cafeteria, University Community
Centre, 7:30 a.m. onwards
Cafétéria du Centre des sciences naturelles,
à partir de 8h.
Cafeteria, Natural Sciences Centre, 8:00 a.m.
onwards.
Dé jeuner :
Lunch:
Cafétéria "Centre Spot", Centre communautaire
universitaire, jusqu'à 14h.
"Centre Spot" cafeteria, University Community
Centre, until 2:00 p.m.
Cafétéria, Centre des sciences naturelles,
jusqu'à 14h.
Cafeteria, Natural Sciences Building, until
2:00 p.m.
Cafétéria "Rainbow Room", Somerville House, de
llh à 14h.
"Rainbow Room" Cafeteria, Somerville House,
11:00 a.m. - 2:00 p.m.
P Restaurant "Room 260", Centre communautaire
universitaire llh30 à 14h.
L "Room 260" restaurant, University Community
Centre, 11:30 a.m. - 2:00 p.m.
P Taverne "Elbow Room", Centre communautaire
universitaire, à partir de midi.
L "Elbow Room" tavern, University Community
Centre, 12:00 p.m. onwards.
P*Faculty Club, Somerville House, llh30 à 14h.
L*Faculty Club, Somerville House, 11:30 a.m. 2:00 p.m.
Dîner:
Dinner:
Cafétéria, Pavillon Saugeen-Maitland, 17h à
18h30.
Cafeteria, Saugeen-Maitland Hall,
5:00 - 6:30 p.m.
Cafétéria "Rainbow Room, Somerville House,
16h30 à 18h30
Rainbow Room cafeteria, Somerville House,
4:30 - 6:30 p.m.
P "Room 260", restaurant, Centre communautaire
universitaire, 17h à 19h30
L "Room 260", restaurant, University Community
Centre, 5:00 - 7:30 p.m.
P "Elbow Room", taverne, Centre communautaire
universitaire, jusqu'à 21h30.
L "Elbow Room" tavern, University Community
Centre, until 9:30 p.m.
P*Faculty Club, Somerville House, 17h30 à 20h30.
L*Faculty Club, Somerville House, 5:30 - 8:30 p.m.
* Cartes de membre temporaire disponibles au
bureau d'inscription.
* Visiting membership cards available at
registration desk.
P Permis d'alcool.
L Licensed under Liquor Control Board of Ontario.
EXPOSITION DES FABRICANTS ET EDITEURS
TECHNICAL AND PUBLISHING EXHIBITION
L'exposition d'équipement technique et de manuels
sera située dans le foyer et les couloirs du
Centre des sciences sociales, tout près des
salles de cours oû se dérouleront les sessions
académiques. Il y a suffisamment d'espace pour
40 kiosques, et déjà (au 10 avril) 19 d'entre
eux sont réservés. Les délégués retrouveront
les exposants habituels de même que certains
membres corporatifs de l'AAPT. Une liste complète
des exposants vous sera remise au moment de
l'inscription.
The exhibition of technical equipment manufacturers
and textbook publishers will be located in the
foyer and corridors of the Social Science Centre
in the immediate vicinity of the lecture rooms
used for academic sessions. Space for 40 booths
is available and almost half of these have been
allocated at the present time (mid-April).
Delegates can expect to see many of the regular
exhibitors plus some of the sustaining members
of the AAPT. A complete list of exhibitors will
be provided at the time of registration.
RAFRAICHISSEMENTS
REFRESHMENTS
Le café sera servi pendant les pauses de l'avantmidi et de l'après-midi.
Coffee will be available mid-morning and midafternoon.
ix
ACTIVITES MONDAINES ET EXCURSIONS
SOCIAL EVENTS AND TOURS
1.
1.
Rencontre
dimanche, 11 juin
Banquet
mercredi, 14 juin
2.
Stratford
mardi 13 juin
3.
Visite au Théâtre du Festival de Stratford
pour voir "A Winter's Tale". Les billets
sont de $13.00 par personne, ce qui comprend
la représentation et le transport, et l'on
doit se les procurer avant midi, lundi.
Départ à 18h30 du Pavillon Saugeen-Maitland.
4.
Communauté mennonite
mardi 13 juin
Musées
mercredi 14 juin
4.
"Le vieux London"
Vous trouverez, à l'inscription, des brochures
qui vous permettront de vous guider dans vos
visites à pied à travers la ville. On vous
y dirige vers les sites historiques d'inérêt
â proximité du centre-ville.
Stratford
Tuesday, June 13th
Mennonite Community
Tuesday, June 13th
This tour will include lunch at a Mennonite
operated restaurant near Elmira, Ontario
followed by a guided tour of Brock's Old
Town Village and the old order Mennonite
community in the surrounding countryside,
featuring farms, wagon factories, blacksmiths' shop etc. Tickets are $10.50 per
person and must be purchased before noon on
Monday. Departure time 10:00 a.m.
5.
Une visite de Eldon House, l'une des
premières résidences de London, que l'on a
transformée en musée; le musée Centennial,
construit par les Industries de la construction et les syndicats ouvriers de London, à
l'occasion du Centenaire canadien; et le
London Regional Art Gallery. Billets: $2.50
par personne; prière de les acheter avant
midi, mardi. Départ à 13hl5.
6.
Wednesday, June 14th
A visit to the Stratford Festival Theatre
has been arranged to see a performance of
"A Winter's Tale". Tickets are $13.00 per
person, including theatre ticket and return
transportation, and must be purchased before
noon Monday. Departure time 6:30 p.m. from
Saugeen-Maitland Hall.
Cette excursion comprend le déjeuner à un
restaurant mennonite près de Elmira, puis la
visite guidée de "Brock's Old Town Village"
et de la communauté mennonite de la campagne
environnante avec fermes, fabriques de wagons,
forges, etc. Billets, $10.50 par personne;
prière de les acheter avant midi, lundi.
Départ à 10h.
5.
Banquet
The University of Western Ontario will host
a reception in the lounge of Saugeen-Maitland
Hall commencing at 6:45 p.m. The CAP
banquet will follow at 7:30 p.m. in the same
building. Tickets are $12.00 per person —
wine included — and must be purchased before
noon on Tuesday.
L'Université de Western Ontario recevra les
congressistes à une réception au Pavillon
Saugeen-Maitland à 18h45. Le banquet de
l'ACP aura lieu à 19h30 dans le même pavillon.
Les billets sont de $12.00 par personne (vin
compris) et l'on doit se les procurer avant
midi, mardi.
3.
Sunday, June 11th
Local physicists and their wives wish to
welcome visitors and renew old acquaintances
on Sunday evening from 7:30 - 9:30 p.m. in
the lounge of Saugeen-Maitland Hall of
residence. All delegates, their wives and
families are invited.
Les physiciens de London et leurs épouses
accueilleront les visiteurs de 19h30 à 21h30
dans le Salon du Pavillon Saugeen-Maitland.
Tous les délégués, leurs épouses et leurs
familles sont les bienvenus. Ce sera une
excellente occasion de renouveler de
vieilles connaissances.
2.
Mixer
Museum - Gallery Tour ... Wednesday, June 14th
An afternoon tour of Eldon House, one of the
first residences of London, Ontario and now
a museum; Centennial Museum built by the
Construction Industries and Labour Unions of
London to commemorate Canada's centennial;
and the London Regional Art Gallery. Tickets
are $2.50 per person and must be purchased
before noon on Tuesday. Departure time
1:15 p.m.
6.
"Old London", Ontario
Brochures describing several self-guided
walking tours of the city will be available
at the registration desk. The tours will
feature sites and buildings of historic
interest within easy walking distance of the
central downtown area.
VISITE DES LABORATOIRES DE RECHERCHE
VISITS TO RESEARCH LABORATORIES
Les délégués pourront visiter certains laboratoires
de recherche de la Cité universitaire: le tunnel
aérodynamique à la Faculté de Génie, le
laboratoire de médecine nucléaire â l'hôpital
universitaire, le centre de physique chimique,
le centre des sciences radio et plusieurs autres
laboratoires du département de physique. Les
intéressés sont priés de prendre les dispositions
nécessaires au bureau d'inscription. On
affichera les heures de toutes les visites
prévues.
Various research laboratories on campus will be
open to congress delegates by arrangement. These
include the Boundary Layer Wind Tunnel in
Engineering Science, the Nuclear Medicine
Laboratory in University Hospital, the Centre for
Chemical Physics, the Centre for Radio Science
and several other laboratories in the Physics
Department. Requests for visits to specific
laboratories should be made at the registration
desk and all scheduled visits will be posted.
IV
LOCAL COMMITTEE
COMITE LOCAL
Président
G.S. Rose
Chairman
Inscription
P.W. Whippey
Registration
Hospitalité & Banquet
J.A. Fulford
Hospitality & Banquet
Programme local
M.I. Wilson
Social Program
Visite des laboratoires
J.A. Fulford
Laboratory Tours
Publicité
J.C.F. MacDonald
Publicity
Salles de conférences
G.F. Lyon
Lecture Halls and A.V.
Exposition
T.W.W. Stewart
Exhibits
Trésorier
M.I. Wilson
Treasurer
Hébergement
P.K. John
Accommodation
Liaison
P.A. Forsyth
Liaison
Pour tous renseignements pendant le congrès,
prière de vous adresser au comité local,
bureaux du département de physique, téléphone:
(519) 679-2289. Le bureau de la presse sera à la
la pièce 3107, et le bureau de l'exécutif de
l'A.C.P. à la pièce 3103, du Centre des
sciences sociales.
The Local Committee may be contacted at the
Physics Department Offices, phone (519) 679-2289.
The Press Room will be located in Room 3107,
and the C.A.P. Executive Office in Room 3103
in the Social Science Centre.
ACTIVITES SPORTIVES
RECREATIONAL FACILITIES
Outre les installations de la ville, les
congressistes auront accès à la piscine, au
gymnase et aux autres installations du Centre
communautaire universitaire pour $1.00 par
personne et par jour. Pour plus de renseignements, s'adresser au bureau d'information du
Centre communautaire universitaire.
In addition to recreational facilities available
in the city, congress delegates may use the
swimming pool, gymnastic and other facilities in
the University Community Centre at a charge of
$1.00 per person per day. Details available at
the information desk in the University Community
Centre.
COIN O P E R A T E D
PARKING LOTS ( 2 5 0
V1
CANADIAN ASSOCIATION OF PHYSICISTS MEDALLISTS 1978
LAUREATS DE L'ASSOCIATION CANADIENNE DES PHYSICIENS 1978
CAP Medal for Achievement in Physics
John M. Robson
Herzberg Medal
Walter N. Hardy
CANADIAN ASSOCIATION OF PHYSICISTS PRIZE EXAM 1978
RESULTATS DE L'EXAMEN DE L'ASSOCIATION CANADIENNE DES PHYSICIENS 1978
One hundred and one students from twenty five universities competed this year. The exam was
administered by A.E. Curzon of Simon Fraser University, Burnaby, British Columbia. The names of
the two students tied for first prize and of the third prize-winner are shown followed by the next
seven in alphabetical order.
A. F. Bielajew
D.B. McColl
E. Talbot
E.E. Bloemhof
J.R. Dahn
T. Draper
P. Ruhe
C. Tessier
B. Quinn
K. Zahnle
McGlll University - FIRST PRIZE
Queen's University - FIRST PRIZE
University of Manitoba - THIRD PRIZE
University of British Columbia
Dalhousie University
University of British Columbia
Univeristy of Waterloo
McGill University
McGill University
McGill University
FUTURE CONGRESSES
CONGRES FUTURS
1979 - University of British Columbia, Vancouver, June 18-21
1980 - McMaster University, Hamilton, June 15-19
1981 - Dalhousie University, Halifax
1982 - Queen's University and Royal Military College, Kingston
CONGRES ACP 1978 CAP CONGRESS
LIST OF EXHIBITORS/LISTE DES EXPOSANTS
As of April 10, 1978
Manufacturers and Suppliers/Manufacturiers et Représentants
ALLAN CRAWFORD ASSOCIATES LIMITED
W.G. ALEXANDER LIMITED
BARRY INSTRUMENT CORPORATION
DATACOMP ELECTRONICS LIMITED
EALING SCIENTIFIC LIMITED
FISHER SCIENTIFIC COMPANY, LIMITED
GUILDLINE INSTRUMENTS LIMITED
ITHACO INCORPORATED
LUCTOR CANADA LIMITED
MERLAN SCIENTIFIC LIMITED
NICOLET INSTRUMENTS CANADA LIMITED
PASCO SCIENTIFIC
RADIONICS LIMITED
Publishers/Editeurs
CANADIAN BOOK PUBLISHERS' COUNCIL
HOLT, RINEHART AND WINSTON OF CANADA LIMITED
PRENTICE-HALL INCORPORATED
W.B. SAUNDERS COMPANY CANADA LIMITED
JOHN WILEY & SONS INCORPORATED
WORTH PUBLISHERS INCORPORATED
v i i i
LISTENERS,
SPECIAL
SPEAKERS, A N D SESSION
INSTRUCTIONS
FOR TIMED
CHAIRMEN
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:
paper and about 10 minutes for an invited paper.
4)
Answer questions and perhaps comments as completely and briefly as made necessary by the
response of the audience.
5)
Obey your chairman's instructions.
6)
Most important, 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.
about 3 minutes for a contributed
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.
4)
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.
ix
INVITED SPEAKERS/CONFERENCIERS INVITES
ABE, K., Betl Northern Research; AA3: Silica Based Glasses for Optical Communication
ARMSTRONG, R.L., Unlverslty
0^ Toronto;
EA2: Rotational Phase Transitions in 5d Transition Metal Antifluorite Crystals
AULD, E.G., University
of British
Columbia.; AC4: Pion Production Using Polarized Protons
BACHYNSKI, M.P., M.P.B. Technologies
Inc.;
EB1: Physicists for Canadian Industry
BANCROFT, G.M. , University
of Western OntaAlo; CA1: Photoelectron Studies of Inorganic Compounds Using Synchrotron Radiation
BEIQUE, R., Hôpital
Notre Vame, Montreal;
ADl: Quality Assurance in Diagnostic Radiology
BERLINSKY, A.J., University
of British
Columbia; AA4: Prospects for Achieving Spin-Polarized Hydrogen
BRUECKNER, K.A., University
0f California,
San Vlego; DB2: Inertial Confinement Fusion
BUDDE, W. , Natlonal
Research Council of Canada; AB4 : Measurement of Spectral Distribution of Solar and Global Radiation
CLEGG, T.B., University
of North Carolina;
AC1: Physics with Polarized Beams
CRADDOCK, M.K., University
of British
Columbia; DC2: Kaon Factories
CR0ZIER, D. , Simon fraser University;
CA2: EXAFS Investigations of Disordered Systems
DATARS, W.R., McMaster University;
DAI: One Dimensional Metallic Incommensurate Chains in Hg2DAVIDSON, R.C., Office of fusion Energy, Department of Energy, Washington; DBA: Alternate Fusion Concepts
DAVIES, K., Environmental
Research Laboratories,
Boulder,
Colorado; CB5: Radio Beacon Studies of the Ionosphere
DAWSON, D., Ontario Cancer foundation,
London; AD3: Quality Assurance in Radiation Oncology
DELISLE, C., Université
Laval; EF1: Research at the Laboratoire de Recherches en Optique et Laser
DESAI, R. , University
of Toronto;
BA3: Dynamics at the Liquid-Vapour Interface
DOBROWOLSKI, G., National
Research Council Of Canada; AB1: Thermal Evaporation of Optical Films
DOLLING, G. , Chalk River Nuclear Laboratories;
EA3: The Plastic-to-Normal Phase Transition in Molecular Crystals
FEARING, H.W., TRIUMF; BB2: Soft Photon Approaches to Nucleon-Nucleon Bremsstrahlung
FLYNN, E.R., Loi Alamos Scientific
Laboratory;
AC3: Direct-Reaction Studies with a Polarized-Triton Beam
FOWLER, T.K., Lawrence Radiation
Laboratory,
California;
DB3: Mirror Fusion
GOLDSTEIN, A., Henry ford Hospital,
Detroit;
EDI : Diagnostic Ultrasound
HAERING, R.R. , University
of British
Columbia; AA1 : Energy Storage and Intercalation Compounds
HARTMANN, G., Max Planck Institut
fur Aeronomle; CB1: Experimental Aspects of Ionospheric Scintillation Observations
HASINOFF, H., University
of British
Columbia; EC2: Recent Progress in Weak Interaction Experiments at TRIUMF
HILL, K.O., Communications Research Centre, Ottawa; CEI: Fibre Optic Device Research in the Department of Communications
HINES, C . o . , University
of Toronto;
FA1: On Getting High
IVEY. R.C.. Abilene christian
University;
EB2: Observations on Applied Physics Education in the U.S.
JANITIS, H., fanshawe College of Applied Arts and Technology;
GA2: Physics in Community Colleges
JASSBY, D., Princeton
Plasma Physics Laboratory;
DB1: Tokamaks and Toroidal Fusion Systems
KANE, G.L., University
of Michigan;
DDI: Current Status of New Quarks and Leptons
KIEFTE, H., Memorial University
of Newfoundland;
BA2: A Brief Review of Brillouin Scattering Experiments in Condensed Matter
KLEIN, M.L., National
Research Council of Canada; DA3: Computer Simulation of Collective Modes in Solids
LACHAMBRE, J.L., VREV, Nou! with Institut
de Recherche
de I'Hydro-Québec;
EF2: Stabilizing the Frequency of TEA-CO2 Lasers
LINDAU, I., Stanford
University;
CA4: Symchrotron Radiation - Present Research and Future Development
McGOWAN, J.Wm., The University
of Western Ontario;
CA3: Soft X-ray Microscopy/Spectroscopy Applied to Research and Development
MICHAUD, G., Université
de Montréal;
BB3: The Implications of Stellar Abundance Anomalies for Stellar Hydrodynamics
MOORCROFT, D.R., The University
of Western Ontario;
FA2: Studying the Upper Atmosphere with Radio Waves
MORRISON, J.A., McMaster University;
EA4: Orientation Ordering and Nuclear Conversion in Solid Methane
NELSON, E. , Simon fraser
University;
DC1: Radio-Carbon Dating Using a Tandem Accelerator
NOXON, J.F., U.S. Department of Commerce; FA3: Optical Studies of the Upper Atmosphere
O'DONNELL, P., University
of Toronto;
DD2: Quark Models and Quark Masses
PALSER, R., Health Sciences Centre, Winnipeg; AD2: Quality Assurance in Nuclear Medicine
PARSONS, R.R., University
British
Columbia; EB4: Spending a Sabbatical Leave in Industry
PAUL, W., Harvard University;
CGI: Amorphous Silicon and Amorphous Silicon-Hydrogen Alloys
REAY, N., Ohio State University;
CC2: The New Spectroscopy
The Next Step
REDNER, S., University
of Toronto;
EA1: The Percolation Threshold in Random and Non-Random Systems
ROBERTSON, R.G.H., Michigan state University;
EC1: Search for Weak Neutral Currents in Nuclei
R0WE, D.J., University
of Toronto;
BB1: Collective Motions and Coherent States
SAYER, M., Queen's University;
AA2: Materials Engineering for New Energy Technologies; EB3: Engineering Physicist-Engineer,
Physicist or Neither?
SKARSGARD, L.D., British
Columbia Cancer foundation;
DC3: Pre-Clinical Studies on the Biomedical it-Beam at TRIUMF
S0FK0, G., University
of Saskatchewan; CB3: Doppler and Polarization Measurements of Auroral Backscatter
STAIRS, D., M c G l t t University;
CCI: Proton-Proton Elastic Scattering at Large Momentum Transfer at 200 and 400 GeV
STEGEMAN, G.I.A., University
of Toronto;
AB3: Applications of Optical Waves Guided by Thin Films; BA1: Brillouin Scattering
at Surfaces
STINSON, R.H. , Ontario
Institute
for Studies In Education;
GA1 : Physical Science in the Intermediate Years
TAYLOR, K., University
of Toronto;
BC1: The Choice of Receptors in Diagnostic Radiology
THOULESS, D.J., Jueen'i University;
BB4: Phase Transitions in Two Dimensions
TUNALEY, J.K.E., The University
of Western Ontario;
CB4: The Effect of Ionospheric Irregularities on Synthetic Aperture Radars
VAN OERS, W.T.H., University
of Manitoba; AC2: Reactions Involving Few Nucléons at Intermediate Energies
WALKER, J.D., Cleveland state University;
BH: Night Flashes: A Multi-Image, Multi-Media Show for Science; GA3: The Flying
Circus of Physics
WALKER, M.B., University
of Toronto;
DA2: Spin-Dependent Oscillations in Metals - a Review of Theory and Experiment
WARD, D., Chalk RlveA Nuclear Laboratories;
EC3: Measurement of G-Factors for Rotational States Using the Enhanced Transient
Field Interaction
WESTWOOD, W.D., BeZl-Northern
Research; AB2: Sputter Deposition of Optical Films
WOLOSHYN, R.M. , TRIUMF and University
of British
Columbia; EC4: Phenomenology of Nuclear Inclusive Reactions at Medium Energy
YEH, K.C., University
of Illinois;
CB2: Characteristics of Radio Signals Randomized by Scattering from Ionospheric
Irregularities
PROGRAM SUMMARY
RESUME DU PROGRAMME
The letter code of the session, the starting time, the location and the topics of each session are
given in order. All sessions will be held in the Social Science Centre.
(The personal names are those of invited speakers).
SUNDAY, JUNE 11
19:30
MONDAY,
AA
AB
AC
AD
AE
AF
AG
2020
JUNE 12
9:00 2024
9:00 2028
9:00 2032
9:00 2036
9:00 3022
9:00 3024
9:00 3026
CAP COUNCIL
Materials for the Future: HAERING, SAYER, ABE, BERLINSKY
Optical Physics I: DOBROWOLSKI, WESTW00D, STEGEMAN, BUDDE
Polarization Phenomena and Nuclear Reactions: CLEGG, VAN OERS, FLYNN, AULD
Quality Assurance in Medical Physics: BEIQUE, PALSER, DAWSON
Molecular Physics
Plasmas produits par laser
Metals, Transport
13:30
13:30
13:30
13:30
13:30
13:30
13:30
2024
2028
2032
3022
3024
3026
3028
Brillouin Scattering: STEGEMAN, KIEFTE, DESAI
Theoretical Physics: ROWE, FEARING, MICHAUD, THOULESS
Radiation Physics: TAYLOR
Nuclei: A<90
Arcs, chocs, plasmas R-F et dynamiques
Spectroscopic Properties of Condensed Matter:Phonons, Magnons, Ferroelectrics, NMR
Semiconductors and Molecular Crystals
16:45
16:45
16:45
16:45
16:45
16:45
16:45
16:45
16:45
2036
2024
3026
2032
3022
3028
2020
3024
2028
Division
Division
Division
Division
Division
Division
Division
Division
Division
20:00
2050
Night Flashes: A Multiple-Image, Multi-Media Show for Science: WALKER
TUESDAY, JUNE
CA
9:00
CB
9:00
CC
9:00
CD
9:00
CE
9:00
CF
9:00
CG
9:00
CH
9:00
13
2024
2028
3006
3022
3018
3024
3026
3028
Synchrotron Radiation: BANCROFT, CROZIER, McGOWAN, LINDAU
Radio Studies of the Ionosphere: HARTMANN, YEH, S0FK0, TUNALEY, DAVIES
Elementary Particles - Experimental: STAIRS, REAY
Nuclei: A>90 and Nuclear Instrumentation
Optical Physics II - Guided-Wave Optics & Holography: HILL
Interactions laser-plasma, développements laser
Amorphous Materials and Random Allocs
Helium, Simple Gases, Liquids and Solids
DA
DB
13:30
13:30
2024
2028
DC
DD
DE
DF
DG
13:30
13:30
13:30
13:30
13:30
2032
3006
3022
3024
3026
DH
16:15
2036
BA
BB
BC
BD
BE
BF
BG
BH
WEDNESDAY, JUNE 14
EA
9:00 2024
EB
9:00 2050
EC
9:00 2036
ED
9:00 2110
EE
9:00 3022
EF
9:00 3024
EG
9:00 3026
EH
9:00 3028
FA
FB
13:30
16:00
16:30
2050
2050
2050
THURSDAY, JUNE 15
GA
9:00 2036 &
11:00 2050
12:00
of
of
of
of
of
of
of
of
of
Aeronomy and Space Physics
Atomic and Molecular Physics
Condensed Matter Physics
Medical and Biological Physics
Nuclear Physics
Optical Physics
Particle Physics
Plasma Physics
Theoretical Physics
Condensed Matter Symposium: DATARS, WALKER, KLEIN
Symposium on Fusion - State of the Art and Prospects: JASSBY, BRUECKNER, FOWLER,
DAVIDSON
Applied Nuclear Physics and Nuclear Instrumentation, NELSON, CRADDOCK, SKARSGARD
Elementary Particles - Theory: KANE, 0'DONNELL
Biophysics
Atomic Physics
Positrons, Diffusion, Damage, Impurities
Division of Physics Education
Phase Transitions and Molecular Solids: REDNER, ARMSTRONG, DOLLING, MORRISON
Applied Physics Education: BACHYNSKI, IVEY, SAYER, PARSONS
Nuclear Physics: ROBERTSON, HASINOFF, WARD, W0L0SHYN
Update on Imaging: GOLDSTEIN
Atmospheric Theory S Measurement
Optical Physics III - Lasers: DELISLE, LACHAMBRE
Confinement magnétique, ondes, instabilités
Layers, Surfaces and Brillouin Scattering
Plenary Session: The Upper Atmosphere: HINES, M00RCR0FT, NOXON
CAP Presidential Address: H.E. JOHNS
CAP Annual General Meeting
Joint CAP/AAPT Education Symposium: STINSON, JANITIS, WALKER
CAP COUNCIL
1
SUNDAY, JUNE 11 ,
ROOM 2 0 2 0
1978
19:30
CAP COUNCIL
Chairman:
H.E. Johns
MONDAY, JUNE 12, 1978
ROOM 2024
Chairman: W.J.L. Buyers
9:00
AA1
MATERIALS FOR THE FUTURE
Energy Storage and Intercalation Compounds.
R.R. HAERING, UrUveAAity
BsUtcih
Columbia
The use of layer compounds as cathodes in electrical energy storage systems will be reviewed. The
underlying physical mechanisms which determine the capacity and discharge rate of such systems will
be discussed. The properties of TiS2 and M0S2 storage systems will be summarized and compared with
the requirements of traction applications.
9:45
AA2
Materials Engineering for new Energy Technologies
M. SAYER, Queen'6 UrUveAAiXy
A number of rapidly advancing areas of technology are presently being limited by materials requirements.
The situation will be reviewed for magneto-hydrodynamic power generation using either clean or particulate
fuels (hydrogen and coal), and for electrodes and electrolytes for batteries and fuel cells. Opportunities
for the application of physics in the field of ceramics and high temperature materials will be discussed.
Engineering solutions have not only to incorporate short term economic considerations but also take into
account projected materials shortages.
10:30
AA3
Silica Based Glasses for Optical Communication.
K. ABE and F.P. KAPRON, B M No^tke/in RZAQjOAch
Communications industries are now experiencing a revolutionary technological change by the introduction
of optical fiber as the guiding channel connecting the transmitter and receiver. In realizing new
applications and in satisfying the needs of systems designers, optical fiber designers and fabricators
must relate the basic physical properties of the waveguide to those factors that produce signal
attenuation and distortion. Essential in this process is the understanding of the basic glass material
itself. This paper will review the state-of-the-art of fiber optic technology, showing how fiber
parameters are closely related to the source and detector components and to the systems applications.
Fiber design and fabrication will be discussed, with an emphasis on how the chemical, thermal,
mechanical and optical properties of silica based glasses fulfill the requirements for optimized
optical fiber and cable. The authors' views on the future development of fiber technology will be
presented.
11:15
AA4
Prospects for Achieving Spin-Polarized Atomic Hydrogen.
A.J. BERLINSKY, UniveAà-Uy ofa B^UXÀ^k Columbia
The pair potential for two hydrogen atoms with parallel electron spins is qualitatively similar to that
of two helium atoms. This fact has led to speculation about possible condensed phases of spin-aligned
H, perhaps the most interesting of which is a Bose-condensed, superfluid phase. This talk will consist
of a review of theoretical predictions of the properties of spin-aligned atomic H, including arguments
concerning its stability. It will also describe experimental programs on this subject which are
underway at U.B.C. and at other laboratories around the world.
MONDAY, JUNE 1 2 , 1 9 7 8
ROOM 2 0 2 8
Chairman:
J.W.Y. L i t
9:00
AB1
OPTICAL PHYSICS I
Thermal Evaporation of Optical Films.
j.A. DOBROWOLSKI, National
Reaeat-ch Council, Ottawa
Examples will be given of a number of more or less classical applications of optical
multilayer coatings.
The underlying principles for the design of such systems will
be presented.
A discussion of the construction parameters of optical multilayer
coatings of this type will show why, up till now, thermal evaporation was the
preferred method for their manufacture.
A description will be given of a typical
thermal deposition system with different types of evaporation sources.
The various
steps of the production process will be enumerated, particular attention being
given to the monitoring of the thicknesses of the constituent layers.
The effect
of both the desirable and undesirable attributes of films produced by thermal
evaporation on the performance of the optical multilayer coatings will be discussed.
Ways for overcoming of some of the difficulties will be described.
9:45
AB2
Sputter Deposition of Optical Films
W.D. WESTWOOD, BM-Hoitk&in R<U><LOJick
More than one hundred years ago, reflective coatings were usually deposited
using rather crude sputtering systems. After a long period in which evaporation
has been the usual deposition technique, sputtering has again become important.
In the last 15 years, a number of new sputtering techniques have been developed
and applied to the preparation of films required for various optical components
including reflectors, filters, photo detectors, waveguides, lasers and solar
energy systems. Sputtering offers a number of advantages in fabricating uniform
films, especially of compounds. With the recent development of magnetron
systems, it is feasible to deposit films over large areas even on plastic
substrates. The various sputtering methods and their applications will be
reviewed with particular emphasis on these for which sputtering offers
considerable advantages.
10:30
AB3
Applications of Optical Waves Guided by Thin Films
G.I. STEGEMAN, UnlvVUlty Off ToiOYVto
Thin films deposited on substrates by R.F. or D.C. sputtering can be used to guide light by total
internal reflection in the film. Typically the best films have losses of db's/cm, thicknesses of
the order of a micron and can support a few waveguide modes. The principal application has been
to study two dimensional guided wave optics and to demonstrate operations useful to integrated
optics. Various examples such as tapered couplers, lenses, beam splitters, etc. will be discussed.
Since the light is confined within one wavelength of the surface and high power densities are
possible, fundamental linear and nonlinear wave interactions have also been investigated. Examples
from Brillouin Scattering, harmonic generation, etc. will be described.
11:15
AB4
Measurement of Spectral Distribution of Solar and Global Radiation
W. BUDDE, National
R&6eoAch Council,
Ottawa
Earlier measurements at NRC of the relative special power distribution of global radiation
(that is total hemispherical incident solar and sky radiation) in the visible part of the
spectrum are described and the results of these measurements are briefly discussed. Of particular
Interest are: the stability of the color temperature of the radiaiton falling on a horizontal
surface and the successful application of a characteristic-vector analysis to such power distributions.
The instrumentation for new measurements of the absolute spectral power distribution of global
radiation in the 300 to 3000 manometer range is described with a particular view of the difficulties
encountered: instability of the measured source, extended wavelength range, large dynamic-range,
geometrical distribution of the incident radiation, calibration of the equipment separation of the
solar component and the sky radiation from the total global radiation, measurement of the radiation
incident on a tilted surface. Since a statistical analysis of these special power distribution is
planned a large number of spectra will be taken over a period of several years. The automation of
the instrumentation will be briefly described.
3
POLARIZATION PHENOMENA AND NUCLEAR REACTIONS
MONDAY, JUNE 1 2 , 1 9 7 8
ROOM 2 0 2 4
C h a i r m a n : F.R. McCourt
9:00
AC1
9:45
AC 2
Physics With Polarized Beams
T.B. CLEGG, Univur&ity
of W o r t h
Carolina.
Reactions Involving Few Nucléons at Intermediate Energies
W.T.H. van OERS, University
of Manitoba
Abundant i n f o r m a t i o n on the e l a s t i c s c a t t e r i n g o f u n p o l a r i z e d and p o l a r i z e d protons from the very
l i g h t n u c l e i a t i n t e r m e d i a t e energies has become a v a i l a b l e i n recent y e a r s . At forward angles
p r e d i c t i o n s based on the m u l t i p l e s c a t t e r i n g eikonal model o f Glauber are i n general agreement
w i t h the experimental data.
D i f f i c u l t i e s e x i s t a t the p o s i t i o n o f the f i r s t minimum (where
s i n g l e s c a t t e r i n g and double s c a t t e r i n g terms i n t e r f e r e ) which can only be resolved by the
i n c l u s i o n o f o t h e r a m p l i t u d e s , e . g . , those corresponding t o i n t e r m e d i a t e A ' s . At backward angles
t h e r e appear t o e x i s t d e v i a t i o n s from a monotonous energy behavior p o i n t i n g t o the importance o f
t r i a n g u l a r graphs which i n c l u d e emission and r e a b s o r p t i o n o f pions c h a r a c t e r i z i n g the s c a t t e r i n g
process.
Q u a s i - f r e e proton s c a t t e r i n g (p,2p) at i n t e r m e d i a t e energies serves t o determine momentum d i s t r i butions.
I f momenta •ï 500 MeV/c are included then these types o f experiments may give informat i o n on the importance o f m u l t i p l e s c a t t e r i n g and/or nuclear c o r r e l a t i o n s .
The a v a i l a b l e data
p o i n t t o an important discrepancy w i t h d i s t o r t e d wave impulse approximation c a l c u l a t i o n s .
•Supported i n p a r t by the National Research Council o f Canada.
10:30
AC 3
Direct-Reaction Studies With a Polarized-Triton Beam*
E.R. FLYNN, Los Alamos Sci.zwU.fio.
Laboratory
A variety of experiments involving direct-reaction studies have now been carried_^out with a
polarized-triton beam of 17-MeV energy. Of particular importance has been the (t,a) reaction
where the large observed analyzing powers permit unique spin assignments for proton-hole states
in nuclei up to and including the actinides. The (?,p) reaction has "been used as a test of
DWBA and CCBA calculations. The (t,d) and (t,t') reactions have also been studied, the former
exploiting the higher angular momentum excited in such stripping reactions while the latter
utilize the +1/2 isospin of the triton. All results were obtained with a Q3D spectrometer with
10- to 20-keV typical resolution. A variety of nuclear structure information has been obtained
from these data and these results will be presented. Supermultiplet symmetry in the 9 Be(t, 6 He)
^Li system will also be discussed.
*Work supported by the U. S. Department of Energy.
11:15
AC4
Pion Production Using Polarized Protons
E.G. AULD, University
of British.
Columbia
The variable energy, polarized proton beam at TRIUMF has been exploited for studying
a) the (p*.it) reaction for targets of 9 Be and 12 C: to the ground state and first few
excited states of 10 Be and 1 3 C and for b) targets of J H and 2 H the particle reactions:
pp + id, imp and pd
nt. The angular distribution of the differential cross-section
and the analyzing power (A,,) have been measured for various incident proton energies
using a .50 m Browne-Buechner spectrograph. The most significant result is the fact
that for all the reactions, A„ is always negative. The significance of this result
will be discussed.
QUALITY ASSURANCE IN MEDICAL PHYSICS
MONDAY, JUNE 12, 1978
ROOM 2036
Chairman: A. Holloway
9:00
AD1
9:45
AD2
10:30
10:45
AD3
Diagnostic Radiology
R. BEIQUE, Hôpital
Not!le Pome, MontréaZ
Nuclear Medicine
R. PALSER, Health
Sciences
Centre,
IVi.nni.peg
Break
Radiation Oncology
D. DAWSON, Ontario Cancer Foundation,
London
MONDAY, JUNE 12, 1978
ROOM 3022
Chairman: A.D. May
9:00
AE1
C o l l i s i o n - I n d u c e d L i g h t S c a t t e r i n g b.y
Compressed Gases o f I s o t r o p i c Molecules.
D. P. SHELTON
AND G. C. TARISZ, U n i y e r s i t y o f Manitoba, Winnipeg,
Manitoba, R3T 2N2. - - Spectra o f the c o l l i s i o n - i n d u c e d
Rayleigh wing have been observed a t d e n s i t i e s up to
150 amagats f o r the i s o t r o p i c molecular gases CHi,, CDu
CFi, and SF 6 . These data w i l l be i n t e r p r e t e d i n
terms o f molecular i n t e r a c t i o n s and o f molecular
dynamics o f the s c a t t e r i n g media. The r o l e o f high
o r d e r molecular p o l a r i z a b i l i t i e s i n the s c a t t e r i n g
process w i l l be reviewed 1 and evidence f o r c o l l i s i o n induced r o t a t i o n a l Raman s c a t t e r i n g w i l l be presented.
1.
A. D. Buckingham and <5. C. T a b i s z , O p t i c s L e t t e r s
1, 220 (1977).
9:15
AE2
Collision-Induced Microwave Absorption in Ne-Xe
and Ar-Xe Gaseous Mixtures. I.R. DAGG, G.E. REESOR and
M. WONG, Univ. of Waterloo—Collision-induced microwave
absorption has been observed at 4.4 cm 1 for the inert
gas mixtures Ne - Xe and Ar - Xe. The absorption
coefficient has been measured at room temperature for
a range of density products up to 15000 (amagat)2 and
for different density ratios. The intracollisional
absorption coefficient has been determined at this
frequency for each mixture from the results at low
densities. These results for the absorption
coefficient along with existing infrared results have
yielded improved values for the zeroth moments and for
the induced dopole moment parameters. The higher
density results reveal intercollision al interference
effects for which the suppression of the absorption
depends on the density ratios of the gases. In the
highest density range studied there is an enhanced
absorption which may be attributed to many-body
collisions.
MOLECULAR PHYSICS
9:30
AE3
Quadrupole Spectrum of p2• A.R.W. McKELLAR and
T. OKA, Herzberg Inst, of Astrophysics, N.R.C.C..
Ottawa —
Although the quadrupole rotation-vibration
spectrum of H2 has been extensively studied since its
first observation1, that of D2 has not previously been
studied. We have observed quadrupole transitions in
the D2 fundamental band CW.8-3.7 pm) using an infrared
difference frequency laser system. The system, based
on the design of Pine2, provides tunable c.w. radiation
in the 2.2-4.2 urn region by mixing light from a
tunable dye laser and a fixed frequency Ar"*" laser in a
temperature-controlled LiNbO-, crystal. The resulting
infrared power is of the order of several nwatt and the
linewidth, essentially limited by the dye laser, is
^ 10 MHz. The spectrum was obtained with a path of
^80 m and a pressure of 1 atm D 2 in a multipletraversal cell. To date we have measured 7 transitions
in the O, Q, and S branches of the 1-0 band with an
absolute accuracy of <0.005 cm . From these measurements. improved molecular constants for the v=0 and 1
states of D2 have been obtained.
'G. Herzberg, Nature 163, 170 (1949).
A.S. Pine, J. Opt. Soc. Am. 64, 1683 (1974); 66, 97
(1976) .
2
9:45
AE4
Absolute Instensity Measurement >f the V 0 Rand of f.0.
G. CHANDRA I AH, Memorial Univ. of Newfound 1 and.---The "
absolute intensity of the 3-0 band of carbon monoxide
has been determined in CO-He gaseous mixture extendinq
the ranqe of foreiqn aas pressures beyond the pressure
necessary for complete broadeninq. The data were
obtained usinq a 1.6R m transmission-type hioh pressure
absorption cell and the Perkin-Elmer Model
double
pass gratinq spectrometer. The plots of the intearated
Intensity vs CO-He aas density is found to be a
straight line with positive slope. The band intensity
value found in the present work is in qood aareement
with those obtained by hiqh-resolution measurements1
and also with the value 2 obtained by employino WilsonWells extrapolation method in pure CO qas. Usina the
existînq theories the square of the rotationless
matrix element and the maqnitude of the Hipolement
coefficient M3 have also been obtained
A. Toth, R. H. Hunt, and F. K. Plvler, J. Mol.
Spectry. }l_t 85 (1969)
2
B. Schurin and R. F. Fllis, J. Chem. Phys.
(1966)
2528
10:00
AE5
Vibrational Pre-Dissociation of van der Waals
Molecules Excited by a Diode Laser. T. E. GOUGH, R. E.
MILLER and G. SCOLES, Guelph-Waterloo Centre for
Graduate Work in Chemistry, University of Waterloo.
Waterloo, Ontario — The separation of isotopes via
photo-dissociation of appropriate chemical bonds is
currently the topic of many experimental and theoretical investigations. We present experimental evidence
for the feasibility of an alternate scheme, using relatively low power C.W. lasers, based upon the vibrational pre-dissociation of the physical bond in a van
der Waals molecule. Considering the dimeric species
(AB) 2 , the vibrational quantum associated with the AB
stretch is typically ten times the dissociation energy
of the physical bond. The possibility exists, therefore, that when (AB)2 is irradiated in the AB stretching region the physical bond will be broken because of
internal energy transfer. This effect has been demonstrated in our laboratory, for nitrous oxide dimers,
in a crossed molecular-laser beam machine which uses a
2 K silicon bolometer to measure the flux of the
molecular beam. In the dissociation process, part of
the excitation energy is transferred into kinetic
energy transverse to the molecular beam resulting in a
decrease in beam intensity.
11:00
Nitrogen Dioxide Resonance Fluorescence
AE8
Intensities.* K.J. CROSS and A.R. HOY, Department of
Chemistry, University of Western On tario - Excitation of
nitrogen dioxide with a tunable dye laser between 5900
and 6500 Â gives rise to strong res onance fluorescence.
By using a narrow excitation line a single vibrationrotation level of the 2 3 2 electroni c state can be
populated. This level subsequently fluoresces to a
series of vibrational levels of the ground electronic
state. The relative intensities of transitions to the
various ground state vibrational le vels have been
measured for several excitation fre<quencies and the
results have been interpreted in te rms of the structure
and vibrational assignments of the upper state.
Work supported by the National Research Council.
11:15
AE9
The Two-photon Excitation Spectrum of Fluorobenzene.* J.C.D. BRAND and R. VASUDEV, Department of
Chemistry, University of Western Ontario- The twophoton excitation spectrum of fluorobenzene vapor has
been recorded in the region of the 1 B 2 -X 1 Ai transition.
The spectrum, excited by a nitrogen laser-pumped dye
laser (bandwidth "0.5 cm" 1 ), shows considerable rovibronic structure with the majority of intensity lying
in the subsystem induced by the V m ( b 2 ) vibration.
Many of the observed bands have been assigned with the
aid of the assignments in the one-photon and infra-red
spectra.1
Two types of rovibronic contours, arising
from AK a =±l and from AK a =0,±2 transitions, are identified. Major features in these contours have been
assigned by comparison with contour-type calculations
using the excited state rotational constants obtained
from the analysis of the high resolution one-photon
absorption spectrum. 2
*
Work supported by the National Research Council.
^ . J . Seliskar and E.D. Lipp, private communication.
10:30
AE6
Unequal Population of A Doublet Levels of NH
following NH3 Decomposition. F. ALBERTI and
A.E. DOUGLAS, National Research Council, Ottawa. —
Using a high resolution spectrograph, we have examined
the optical emission which follows the dissociation of
NH3 by 1215 ® radiation. As had been observed earlier,
the strongest feature of this emission is the 0-0 band
of the c ^ - a ^ system of NH at 3240 & which results
from the process NH3 + hv
H2 + NH(C1I1). The lines of
this band are doublets as a result of the A doubling in
the two electronic states. Our surprising observation
is that the two components of the doublets are of
unequal intensity with intensity ratios varying from
1.1 at J'=8 to 2.4 at J'=17. Experiments will be
described which show that the unequal intensities
result from a difference in the populations of the two
levels of the A doublets of the c1!! state following the
dissociation of NH 3 . It will be shown that this
population difference can not have its origin in the
energy difference of the levels but must, in some
unknown way, be related to the parity of the levels.
10:45
AE7
^ s e r Induced Fluorescence Study nf rhe 64 71 A
3and of : '*N 16 0?.* j T c . D . BRAND, K.J. CROSS and A.R.
HOY, Department of Chemistry, University of Western
Ontario - Rotational assignments in the 6471 Â band of
NO2 vapour nave been determined from shifts in the
laser fluorescence excited by a tunable dye laser
source. Approximately two hundred and fifty fluorescence transitions have been assigned rotational quantum
numbers and identified with transitions observed in absorption. Since the fluorescence intensity distribution is characteristic of a "parallel" band the excited
state must have B 2 vibronic symmetry. Perturbations of
the rotational energy levels are widesprecd and the
derived rotational constants must be viewed as "effective" parameters. Most of the perturbations are attributed to vibronic coupling, involving high vibrational levels of the electronic ground state. Analysis
of the perturbations provides information on the magnitude of matrix elements coupling the 2 B 2 and 2Ai
(ground) electronic states and the magnitude of the
rotational constants in the 2 AI .states.
2
G.H. Kirby, Molec. Phys., 19^, 289 (1970).
11:30
AE10
Relaxation magnétique protonique de la molécule
d'ammoniac à l'état gazeux. C. LEMAIRE and R.L.
ARMSTRONG, Univ. of Toronto.—On présente les résultats
d'une étude expérimentale du phénomène de relaxation
magnétique nucléaire des protons de la molécule
d'ammoniac à l'état gazeux. Les données obtenues
permettent d'établir le comportement du temps de
relaxation longitudinal pour des densités allant de
1 à .003 amagat, à la température de 300 K. La
fréquence utilisée pour réaliser ces expériences est
de 6l MHz. L'allure générale de la courbe caractéristique obtenue, en particulier, l'existence d'un temps
de relaxation minimum conforme aux prédictions
théoriques, offre une première démonstration expérimentale de l'applicabilité, aux molécules du type
toupie symmétrique, des divers modèles théoriques
décrivant ce phénomène aux faibles densités. En
particulier, on confirme la prédominance de l'interaction spin-rotation sur l'interaction dipolaire dans
le mécanisme de relaxation longitudinal. Une évaluation de la section efficace de réorientation angulaire
est aussi obtenue de ces données.
11:45
AE11
M-Dependence of Rotational Energy Transfer in a
Four-Level System of Methyl Alcohol.* R. M. LEES,
Univ. of New Brunswick— A steady-state microwave
double resonance experiment on the (4_i"*~3q) p- U g ^ i ) 5
four-level system of methanol in the presence of a
Stark field has been carried out in order to study
collision-induced rotational transitions between individual M-components of the pump and signal levels.
The double resonance spectrum has been obtained for
signal M-components having Ms=0, -1, -2 and -3. The
polarities and relative magnitudes of the double resonance signals are in quite good agreement with a very
simple dipolar model in which the only variable for a
collisional rate constant is the square of the dipole
matrix element for the transition.
•Supported by the National Research Council of Canada
Work supported by the National Research Council.
PLASMAS PRODUITS PAR LASER
MONDAY, JUNE 12, 1978
ROOM 3024
Chairman: F . L . Curzon
9:00
Complex Electron Density Structures in the
AF1
Initial Stages of Laser-Plasma Interaction. B. GREK,
F. MARTIN, H. PEPIN, F. RHEAULT, T.W. JOHNSTON, INRSEnergie, Univ. du Québec, C.P. 1020, Varennes, P.Q.,
JOL 2PO. —
Interferometry and Schlieren have been
done using a synchronized short pulse (20 psec) ruby
laser on the plasma created by a short CO2 laser pulse
(12J, 1.7 nsec) incident on polyethylene slab. The
results indicate clearly the formation of remarkable
density structures in the (C02) overdense plasma
(ne > 10 19 cm" 3 ) during the first few tenths of nanoseconds, smoothing out at later times. Since Abel
inversion is manifestly inapplicable and ruby ray
bending important, we have resorted to inventing
plausible plasma models with a complete ray tracing
program - including the optical system- to simulate
results,to be relaxed to Che observations by adjusting
the plasma model parameters. The raw results and
their Interpretation will be discussed.
9:15
AF2
Density Modification in Stimulated Brillouin
K.J. PARBHAKAR, T.W. JOHNSTON, INRS-Energie, Univ. du
Québec, C.P. 1020, Varennes, P.Q., Canada, JOL 2P0.~
Plasma density modification can be usefully analysed
in a frame with is stationary with respect to the density modulations. The analysis is very similar to the
previous analyses of the behaviour near the critical
density surface. In this frame the incomming and outgoing waves are Doppler-shifted to the frequency midway between their laboratory values. The distinction
between the subsonic and supersonic case is easily
made and the non-sinusoidal profile modifications can
be readily calculated.
10:00
AF5
Characterisation of High Harmonic Emission
from CO, Laser-Produced Plasmas. H.A. BALDIS,
N.H. BURNETT, M.C. RICHARDSON and G.E. ENRIGHT, N.R.C.Recently, in studies of the interaction of intense
W cm"2) 10.6 Jim radiation with matter, we have
10
observed the emission of a series of integral harmonics of the incident radiation. (1) We now wish to report further characterisation of this emission, in
particular its dependence on laser intensity. Preliminary results suggest a power law dependence of the
intensities of these harmonics with increasing laser
< 1 , ^ for
intensity of the form I r
10 13 w cm"? with apparent saturation above
this level.
(1)
10:15
AF6
Picosecond Time, and Space Resolved Study of
High Harmonic Emission from C03 Laser-Produced Plasmas,
P. JAANIMAGI, G.D. ENRIGHT and M.C. RICHARDSON, N.R.C.Earlier investigations of the interaction of intense
( 10 W cm" ) nanosecond duration 10.6 )j.m pulses with
solid targets have identified an integral series of
harmonics in the side and backscattered radiation? We
now wish to report initial measurements of the temporal
and spatial characteristics of the 10th and 11th harmonics in the side-scattered light made with the aid of
a picosecond streak camera.
*
9:30
AF3
Absorption Characteristics of Nanosecond C02
Laser Pulses by Solid Targets at High Irradiance Levels
D.M. VILLENEUVE, G.D. ENRIGHT and M.C. RICHARDSON,
N.R.C.— Measurements, made using both 2TT infrared
light balance techniques and direct ion calorimetry, of
the fractional energy absorption at irradiance levels
of ^10lt+W cm""2 will be presented. The dependence of
absorption on focussing conditions, and the nature of
the angular distribution of ion energy and scattered
IR radiation will be discussed in terms of current absorption theories.
9:45
AF4
Interferometrie Measurements of Radiation PresR. FEDOSEJEVS?
sure Effects in Laser-Produced Plasmas
G.D. ENRIGHT, I.V TOMOV** ard M.C. RICHARDSON, N.R.C.Picosecond optical interferometry at 0.53 ^un, of the
plasmas produced by the 1 ns, 10.6 |im laser pulse from
the COCO-II C02 laser system allow time-resolved measurements of the electron density profile over a range
of incident intensities up to 2 * 10ll4W cm - 2 . Interferograms displaying the plasma profile from one tenth
to several times critical density show a steepening in
the critical density region at intensities £l0 13 W cm - 2 .
These observations agree with predictions of density
profile modification for intensities at which the
radiation pressure becomes comparable to or greater
than the local plasma kinetic pressure in the critical
density region.
University of Toronto
Present address: Sofia University, Sofia, Bulgaria
N.H. Burnett, H.A. Baldis, M.C. Richardson,
G.D. Enright, Appl. Phys. Letts., 31, 172 (1977).
N.H. Burnett et al., Appl. Phys. Letts.
(1977) .
31, 172
10:45
AF7Superthermal X-ray Emission from CO, LaserProduced Plasmas, G.D. ENRIGHT, M.C. RICHARDSON and
N.H. BURNETT, N.R.C., — One beam of the COCO-II CO,
laser system has been used to irradiate plane targets
at intensities up to 2 x 10lt+W cm"2. The superthermal
component of the x-ray emission spectrum yields information about the production of fast electrons. This
emission spectrum can be characterized by a hot electron temperature, T H , which we have found to be particularly sensitive to the focussing condition and somewhat less dependent on laser power, irradiance angle,
and target composition. These results will be compared
with those obtained using 1.06 >im irradiation.
11:00
AF8
XUV Spectroscopy of the Directionally Expanding
CO, Laser-produced Plasmas, N.A. EBRAHIM, M.C. RICHARDSON
0. FELDMAN*, G.D. ENRIGHT, and G. DOSCHEK*, N.R.C., —
Two-dimensional monochromatic images of COa laserproduced plasmas have been obtained in the spectral
region 20u A - 500 A using a slitless normal incidence
spectrograph (spectroheliograph). Space-resolved
electron densities have been determined from such
spectroheliograms by spectral line intensity ratios in
the extreme ultraviolet. Studies of XUV transitions
within highly ionized species of Al, Fe, Ti and Si will
be discussed and a possible application of this new
plasma diagnostic technique suggested.
*
Naval Research Laboratory, Washington, D.C.
20375
7
11:15
AF9
Fine Structure of Backscatter during CO? Laser
Plasma Interaction. G. MITCHEL and B. GREK, INRSEnergie— A study has been made of backscattered radiation at 10.6 y from the interaction of a 10 Joule,
1.5 ns CO2 laser pulse with a polyethylene target.
This accounts for < 10% of the total incident energy.
Direct imaging of the backscatter at the laser frequency onto silver halide films followed by visible
fogging shows fine structure in the reflectivity of
the plasma. This structure may be correlated with
evidence of filamentation and of ejection of jets of
plasma as seen by interferometry and shadowgraphy with
a synchronised ruby laser of pulse duration 20 ps. Infrared spectra of the backscatter near 10.6 y will
also be presented.
11:30
AF10
Enhanced Thomson Scattering from PlasmaFluctuations Excited by C02 Lasers, J.C. SAMSON,
H.A. BALDIS and P.B. CORKUM, N.R.C. — Thomson
scattering employing a 2 ns, 0.53 fim beam has been
used to study the interaction of a short (5 ns) C02
laser pulse with plasmas at electron densities between
critical ( 10 1 9 electrons/cm 3 ) and one tenth critical.
The peak intensity of the focussed C02 radiation was
approximately 5(10 1 2 ) W/cm 2 . Near the critical density, the scattered spectra show strong enhancements in
both the ion and electron features. Enhancements in
the electron feature at quarter critical densities
give strong evidence for two-plasmon decay instabilities in this region, although the enhancement decreases
markedly within 2-3 ns of the beginning of the C02
pulse.
MONDAY, JUNE 1 2 , 1978
ROOM 3026
Chairman:
F . T . Hedgecock
9:00
AGI
The Electrical Resistivity of Potassium below
4K. J.A. ROWLANDS, C. DUVVURY and S.B. WOODS, Univ.
of Alberta.—Recent measurements 1 of the temperature
dependent resistivity p^, of potassium down to 1.IK
have indicated the presence of an unexpected new term
AT n with 2>n>l and A a p 0, the residual resistivity.
We have used a dc current comparator and SQUID null
detector 2 to measure p T down to 0.5K where p^, ^ 10 4 p
in order to examine this term more closely; we
confirm that A « p Q and n = 1.5. We will present
results on specimens of different purity and diameter
that lead us to believe that we are observing a size
dependent electron-electron resistivity.
1
H. van Kempen, J.S. Lass, J.H.J.M. Ribot and P. Wyder,
Phys. Rev. Letts. 37.» 1574, 1976.
2
J .A. Rowlands and S.B. Woods, Rev. Sci. Instr. 47_,
795, 1976.
9:15
AG2
Unambiguous Separation of N and U ElectronPhonon Scattering in K at Low Temperatures. M.R. STIFSON and R. FLETCHER, Queen's Univ.—Although Normal and
Umklapp electron-phonon scattering processes both contribute to the various transport properties of metals
(e.g. thermopower and resistivity) distinguishing the
relative contributions of each has in the past been a
difficult problem. However, an unambiguous separation
is possible when the off-diagonal components of the
thermoelectric tensor (exy) are considered in the limit
of high magnetic fields. For this case the diffusion
contribution becomes independent of the scattering and
can be directly related to the measured specific heat;
the remaining phonon drag term is free of many body
effects and allows us to distinguish the relative contribution of the N- and U-processes. The present paper
reports simultaneous measurements of the Nernst-Ettingshausen, Hall and Righi-Leduc coefficients on samples
of K (RRR £ 5000) in fields up to U.5 T, at temperatures between l.U and U.U K. From these the phonon
drag portion of Zy-y was extracted and found to be in
good agreement with recent calculations by Leavens.
Umklapp scattering events begin to become important
near 2.0 K.
9:30
AG 3
The_ Kondo_ Ef f ec_t_ in_ Au_._ R.J. BARTON and
J.F. KOS,"Univ]~of~Re^~ina"-- The electrical resistivity
of Au was determined from 1.33°K to room temperature.
The samples contained about .2 ppm of Fe (determined
spectrographical1y) which was oxidized to effective
concentrations between about .005 and .2 ppm. These
concentrations are well below the limit set by the
RKKY interaction between impurity atoms and thus the
isolated scatter model of Hamann 2 should apply. The
data was compared to this model using an iterative
least square procedure with a linearized variance
equation. A Kondo temperature of 1.5°K. was obtained.
D.R. Hamann, Phys. Rev. J58, 570 (1967).
METALS, TRANSPORT
9:45
AG4
Pressure Dependence of the de Haas-van Alphen
Effect in Potassium
Z. ALTOUNIAli, C. VERGE
W.R. DATARS. McMaster U . — T h e pressure dependence of
the de Haas-van Alphen effect in potassium has been
studied up to 4.6 kbar. The measured dHvA frequencies
were lower than the free-electron scaling predictions
for all pressures. The low pressure area compressibility of the Fermi surface was found to be 15% lower
than the free-electron value. The results show the
failure of the free-electron theory for potassium.
The decrease in both the Fermi surface cross sections
and the area compressibilities indicate the possible
existence of a new ground state energy. The chargedensity wave model is suggested by the presence of
beats in the dHvA oscillations and the orientation
dependence of the Fermi surface distortions induced
by pressure.
10:00
AG5
Pressure Dependence of the Fermi Surface of
ReQ3.
F.S. RAZAVI, Z. ALTOUNIAN and W.R. DATARS.
McMaster U . — D e Haas-van Alphen frequencies of ReO^
have been measured as a function of pressure up to
5 kbar with the magnetic field along [111] and [001]
crystallographic directions. With pressures up to 3
kbar, the compressibility of Fermi surface crosssectional areas in the first zone follow the free
electron scaling predicted from tne volume compressibility. The pressure dependence of cross-sectional
areas in all zones is anomalously large between 3 and
4.2 kbar where each zone's area compressibility is
8-20 times larger than its low pressure area compressibility. This is evidence of a large volume compressibility in this pressure interval. The measured g
factor is pressure independent up to 5 kbar.
10:15
AG6
Core Charge Polarization Effects on the Knight
Shifts in the Alkali Metals. R. A. MOORE, J . D. KEllf,
W.T. HYDE, Univ. of Waterloo, and C.F. LIU, Kaohsiung
Teacher's College.—With the occurrence of new
experimental results it is appropriate to re-assess
previous calculations of the Knight shift and at the
same time with the innovation of improved theoretical
models to include correlation effects through the
inclusion of core charge polarization. A comparison is
made of the results obtained by using a local scalar
effective potential in the one-electron approximation
for the conduction electron obtained from the HartreeFock-Slater procedure, the Hartree-Fock procedure, the
Kohn-Hohenberg-Sham density formulation, and a recent-L
core charge polarization model. The calculations are
carried out in the Wigner-Seitz spherical cellular
approximation. One sees, by means of the core charge
polarization model, that correlation effects are significant and, by comparing the different results, that
the Knight shift is sensitive to the choice of cellular
potential.
loore, R.A. and Liu, C.F., Phys. in Can. 33, 27 (1977).
8
10:45
AG 7
Core Charge Polarization Effects on the gshift3 in the Alkali Metals* W.T. HYDE, J.D. REID, R.
A. MOORE, Univ. of Waterloo, and C.F. LIU, Kaohsiung
Teacher's College.—All previous attempts at calculating the g-shifts in the alkali metals have given
large discrepancies with observation for rubidium and
cesium. These differences were attributed to core
charge polarization due to the conduction electrons.
Very recently, a modell of core charge polarization
with the capability of being applied to this problem,
among others, was developed. The calculations were
carried out in the spherical cellular approximation
and one finds that core charge polarization effects do
not remove the abovementioned discrepancies. In
addition, the effect of other approximations going
into the effective potential appearing in the oneparticle Schroedinger equation for the conduction
electron is examined. The g-shift turns out to be
very sensitive to small changes in this potential with
indications that some self-consistency is required.
11:30
AGIO
F i n i t e D i f f r a c t i o n Models f o r E l e c t r o n Band
Structures^
P.P. LOLY and A. BAHURMUZ, Univ. o f
Manitoba - Approximations t o the spectrum o f an e l e c t r o n i n a cosine p o t e n t i a l i n one dimension t h a t use
f i n i t e sets o f r e c i p r o c a l l a t t i c e v e c t o r s are c r i t i c a l l y analysed. Emphasis i s placed on t h e i r a b i l i t y
t o reproduce the p r o p e r t i e s o f the d e f i n i t i v e (Mathieu
problem) s o l u t i o n .
I t i s necessary t o use symmetric
sets (odd determinants) i n order t o ensure paraboli c i t y a t the zone centre and a minimum 3x3 model i s
suggested. Acceptable behaviour a t the zone boundary
f o r the lower bands r e q u i r e s a 5x5 model which i s i n
e x c e l l e n t agreement w i t h the Mathieu expansions a t
band edges and i n t e r m e d i a t e p o i n t s .
Extensions t o
higher dimensions are discussed.
Hloore, R. A. and Liu, C.F., Phys. in Can. 33, 27 (1977)
*Supported in part by the Nat. Res. Council of Canada
11:00
AG8
Uniaxial Strain Dependence of the Fermi Surface
of Tin.
D.K. MAK and J.M. PERZ, Univ. of Toronto—
The derivatives, with respect to uniaxial strain along
[001], of extremal cross sectional areas of the Fermi
surface of tin normal to the [001] and [100] directions
have been determined experimentally from simultaneous
measurements of quantum oscillations in sound velocity
and torque. A local pseudopotential model has been
used to calculate these strain derivatives from parameters fitted to describe the unstrained Fermi surface.
Quantitative and qualitative agreement is obtained
between the results of the model calculation and our
data as well as experimental data from other sources.
11:15
AG9 Electron Interference Oscillations in Antiferromagnetic Chromium.* F.W. HOLROYD, R. REIFENBERGER,
E. FAWCETT, Univ. of Toronto—Oscillations in the
transverse magnetoresistance of antiferromagnetic
chromium exhibit two features which are characteristic
of the quantum interference of electron states along an
open orbit direction. Firstly, the frequencies
observed in the oscillatory magnetoresistance are
different from those measured in de Haas-van Alphen
experiments, and secondly, the amplitude of the magnetoresistance oscillations is independent of temperature in the liquid helium range. For Q||[001],
j||[010] and H in the (010) plane, electron interference in antiferromagnetic chromium may occur because
of magnetic breakdown at the energy gaps caused by an
incommensurate spin density wave. New measurements
which confirm previous observations1 will be presented,
and a possible interpretation of these results based
on an electron interference effect will be discussed.
*
Research supported by the National Research Council of
Canada
1
A.J. Arko, J.A. Marcus, and W.A. Reed, Phys. Rev. 185,
901 (1969).
11:45
AG 11
Interatomic Potentials from the Pensity Functional Formalism.* M. D. WHITM0RE** and J . P. CA¥BOTTE,
McMaster Univ.—A procedure has been developed for calculating the interatomic potential V(R) in a metal directly from non-linear self-consistent calculations of
the electron response to an ion imbedded in an electron
gas. The procedure involves integrating over all space
the various terms contributing to the energy of the
two interacting screened ions E[p(r)], where p(r) is
the total charge of the two overlapping ions separated
by a distance R. Some applications are briefly discussed.
* Work supported by National Research Council of
Canada
"Permanent address: Department of Physics, Memorial
University of Newfoundland, ST. John's, Newfoundland,
Canada
12:00
AG12
The Anharmonic Properties of Li*. S.H. TAOLE
and H.R. GLYDE, Physics Department, University of Ottawa
and ROGER TAYLOR, Division of Physics, National Research
Council of Canada,-- The energies and lifetimes of
phonons in metallic Li between 110 and 424K are
calculated using self consistent phonon theory and the
effective ion-ion interaction developed by Dagens,
Rasolt and Taylor (DRT). The results are compared with
the recent neutron scattering measurements of Beg and
Nielson. Li turns out to be surprisingly harmonic,
less anharmonic than Na or K, due to the strong Li
ion-ion interaction which has a relatively soft
repulsive core. While the overall agreement with
experiment is good, the remaining discrepancies
suggest (1) the presence of three of four body
interactions in Li which are not included in the DRT
pseudopotential method and (2) that the phonons decay
significantly via processes higher than those accounted
for by cubic anharmonicity.
9
BRILLOUIN SCATTERING
MONDAY, JUNE 1 2 , 1 9 7 8
ROOM 2 0 2 4
Chairman:
F.R. McCourt
13:30
BA1
Brillouin Scattering at Surfaces
G.I. STEGEMAN and N. ROWELL, UrUvZAixCty of Toronto
The observation and interpretation of Brillouin Scattering from the surfaces of semi-conductors
and metals and from deposited films is a recent development. The spectra originate from scattering by thermal surface waves and by a continuum of bulk phonons. They are characterized by
wavevector conservation in the plane of the surface only. The correct theoretical interpretation
was reported in early 1978 and has led to an understanding of phonon modes and the acoustooptic
interaction at surfaces.
It is now possible to evaluate the elastic and elastooptic properties
of materials at surfaces and this technique may well prove to be a valuable tool in surface
physics.
14:15
BA2
A Brief Review of Brillouin Scattering Experiments in Condensed Matter
H. Kief te, Memo/Ual UnJjjvuÀXy
of
Newfoundland
Brillouin scattering in fluids and solids is caused by fluctuations in the dielectric
constant due to therroa11y-excite^ elastic or acoustic waves. The theory of spontaneous
P-rillouin scattering, t h e aooaratus and more recent technioues used, and various experiments
will be reviewed, particularly as applicable to the measurement of elastic and photoelastic
constants and the acoustic or phonon attenuation in transparent bulk solids and crystals.
The study of phase transitions in such systems will also be discussed.
15:00
15:15
BA3
Break
Dynamics at the Liquid-Vapour Interface
R. DESAI, UnÀvzA&Àjty of
Toronto
Hydrodynamics of surface waves at the gas-liquid interface will be reviewed. Recent advances in
our understanding of the dynamical origin of capillary waves will be outlined. The concepts of
broken symmetry and Goldstone modes will be applied to dynamical correlations in an inhomogeneous
fluid. The correct form of capillary wave dispersion will be deduced in two ways: first via
generalised hydrodynamics and then from kinetic theory.
16:00
Rotational Relaxation in HP-He Gas Mixtures*
W.-K. LIU and F.R. McCOURT, Chem. Dept., U. of WaterlooRelaxation and kinetic cross sections have been calculated within the distorted-wave Born approximation (DW
BA) for HD infinitely dilute in He. The potential energy surface for HD-He was obtained from that for H2-He
using a numerical transformation procedure 1 . The cross
sections so obtained are related to sound absorption
experiments, NMR Ti relaxation times and SenftlebenBeenakker effects (SBE). It is shown that in sound absorption, the traditional single relaxation time description breaks down at temperatures higher than 100 K
and a multi-level description is needed.
Comparison
with existing exact CC calculations shows that while
the magnitudes of the cross sections are overestimated
by about 30% on the average, the trend (behaviour as a
function of incident energy) is mimicked well by the
DWBA. Hence although the relaxation parameters calculated within the DWBA should be used with caution, the
temperature dependence as calculated within the DWBA
may be used as a guide for future experiments.
W.-K. Liu, J.E. Grabenstetter, R.J. Le Roy and F.R.
McCourt, J. Chem. Phys. (in press).
*Supported by the National Research Council of Canada
16:15
BA5
T h e R a y l e i g h - B r i l l o u i n S p e c t r u m of
H y d r o g e n at H i g h D e n s i t i e s *
A. D. M A Y , M.
H U B E R T and V. G H A E M - M A G H A M I , U n i v . of Toronto.T h e Ray l e i g h - B r i 1 l o u i n s p e c t r u m of light
s c a t t e r e d from h y d r o g e n at h i g h d e n s i t i e s is
reported.
The o b s e r v a t i o n s are c o m p a r e d w i t h
t r a n s l a t i o n a l h y d r o d y n a m i c t h e o r y and u l t r a sonic e x p e r i m e n t s .
The r a n g e of d e n s i t i e s
i n c l u d e s the r e l a x a t i o n r e g i o n and we find
e v i d e n c e for m u l t i p l e r e l a x a t i o n .
A mean
r e l a x a t i o n t i m e for n o r m a l h y d r o g e n at 2 4 ° C
8
of ( 1 . 4 1 ± . 0 6 ) x 1 0 "
s e c . is found in a g r e e ment with theoretical c a l c u l a t i o n s .
* W o r k s u p p o r t e d in p a r t by the
R e s e a r c h C o u n c i l of C a n a d a
National
10
MONDAY, JUNE 1 2 , 1 9 7 8
ROOM 2 0 2 4
Chairman:
F.R. McCourt
13:30
BB1
THEORETICAL PHYSICS
Collective Motions and Coherent States
D.J. ROWE, University
o^ Toronto
For a simple harmonic oscillator, the classical concept of harmonic motion is beautifully realized
in quantum mechanics by the non-dispersive coherent states of Glauber. These coherent states
have been variously deployed in the microscopic description of collective normal mode vibrations
of many-particle systems. However, there are many other kinds of coherent states and it will be
shown how these can lead to elegant realizations of a much richer class of collective motions.
Illustrative examples will include the coherence properties of the two-photon laser and the rotations and shape vibrations of nuclei.
14:15
BB2
15:00
BB3
Soft Photon Approaches to Nucleon-Nucleon Bremsstrahlung
H.V. FEARING, TRIUMF
The Implications of Stellar Abundance Anomalies for Stellar Hydrodynamics
G. MICHAUD, Université
de Montréal
Some 20 percent of the stars more massive than 1.3 M show abundances that do not fit into the
currently accepted nucleosynthesis model. I will describe how element segregation in the outer
parts of those stars explains those anomalies. The implied stability of the outer stellar layers is
surprising. The details of the abundance anomalies act as a probe of the outer stellar hydrodynamics
15:45
BB4
Phase Transitions in Two Dimensions
D.J. TH0ULESS, Queen's
University
The theory of phase transitions for two-dimensional solids, superfluids and planar magnets
will be reviewed. The dislocation (vortex) theory predicts a value for the ratio between
rigidity (superfluid density) at the transition temperature and the transition temperature.
Recent evidence in favour of this will be discussed.
MONDAY, JUNE 12, 1978
ROOM 2032
Chairman: M. Cohen
13:30
BC1
The Choice of Receptors in Diagnostic Radiology
K. TAYLOR, University
of Toronto
RADIATION PHYSICS
11
14:15
BC2
Proposed Canadian Performance Standards
for Diagnostic X-Ray Equipment - W.M.ZUK and
P.DVORAK, Radiation Protection Bureau, Health
and Welfare Canada•--Exposure from diagnostic
radiology accounts for more than 90% of the
total exposure received by the population
from man-made sources of ionizing radiation.
According to experts in the scientific
community, the average exposure from diagnostic radiology can be reduced significantly
through improvements in the design of medical
x-ray equipment.
To ensure that only welldesigned, safe equipment is sold in Canada,
the Radiation Protection Bureau has developed
standards of design, construction and performance, for promulgation under the Radiation
Emitting Devices Act.
The salient features of
these proposed standards will be discussed,
with particular emphasis given to the performance requirements.
14:30
BC3
Quality Assurance X-Ray Uavefnm Imaging
Techniques. A.M. SOURKES, D.M. LEE "and A.F. IIOLLOV.'AY,
Manitoba Cancer Foundation. — In a Quality Assurance
x-ray measurement program, x-ray waveform monitorinp,
equipment forms an essential part of the test procedure. This waveform imaging test can readily ileiect and
assure proper machine kV switching timer accuracy,
wave rectification and target condition. By usinn
additional filtration just above the waveform detector,
switching levels can be ascribed to kV or r.iA variation
in the generator equipment. Three such waveform imaging techniques are presented and evaluated regarding
their relative merits.
15:30
BC6
The Present State o f Medical Neutron Dosimetry.
K.W. GEIGER, National Research Council o f Canada"!
Ottawa — R a d i o b i o l o g i c a l experience has shown t h a t
d i f f e r e n c e s i n absorbed neutron dose o f less than 10%
can be recognized. Several groups around the w o r l d
have now i n i t i a t e d p r o j e c t s i n neutron r a d i o t h e r a p y .
To assess the d i f f e r e n c e s i n absorbed dose measurements
between l a b o r a t o r i e s , the I n t e r n a t i o n a l Commission on
Radiation Units and Measurements (ICRU) organized an
i n t e r n a t i o n a l neutron dosimetry intercomparison ( I N D I ) .
The p a r t i c i p a n t s made t h e i r measurements a t BNL and the
a n a l y s i s o f the r e s u l t s has j u s t been completed.
Dosimetry to a d e s i r e d accuracy o f +3% was not achieved,
nor could the r e s u l t be improved by a r e - a n a l y s i s using
uniform c o r r e c t i o n s between the p a r t i c i p a n t s .
15:45
BC7
Why Accurate Measurements o f Neutron Dose
Equivalent are P r a c t i c a l l y Impossible. D.W.O. Rogers,
NRC, Ottawa - - Although most nuclear i n s t a l l a t i o n s use
remmeters as a measure o f the neutron dose e q u i v a l e n t
(DE) received by workers, they do not g i v e an accurate
value f o r t h r e e reasons:
i ) the d e f i n i t i o n o f DE i s
d i r e c t i o n a l l y dependent which means t h e r e i s an unc e r t a i n t y o f a f a c t o r o f 3 i n the measurement unless
the angular d i s t r i b u t i o n o f the f l u x i s k n o w n ; o i i )
d e s p i t e the m a n u f a c t u r e r ' s claims o f ±20% accuracy, our
c a l i b r a t i o n data show t h a t these instruments o v e r respond by a f a c t o r o f f i v e t o 20 keV n e u t r o n s ; i i i )
the ICRU and NCRP have recommended neutron f l u e n c e t o
DE conversion f a c t o r s which d i f f e r by a f a c t o r o f t w o . 1
Hence, remmeters can g i v e gross o v e r - e s t i m a t e s o f DE.
In view o f R o s s i ' s c l a i m t h a t "maximum p e r m i s s i b l e
neutron doses must be r e d u c e d " , 2 these over-responses
could pose serious o p e r a t i o n a l l i m i t a t i o n s unless they
are recognized and solved.
'D.W.O. Rogers, Health Physics, i n press.
2
14:45
BC4
Absorbed Dose Calibration of a Sagittaire
Linear Accelerator. D. V. CORMACK, A. F. HOLLOWAY
and H. BOESE, Manitoba Cancer Foundation -The
Sagittaire linear accelerator installed in the
Manitoba Cancer Foundation generates electron beams
from 7 MeV to 32 MeV and a photon beam with a
maximum energy of 25 MeV. Our absorbed dose calibrations are based on ferrous sulfate dosimetry which
has been compared in a
Co beam with an N.R.C.callbrated ionization chamber. The calibration
factor (rads/monitor unit) Increases with dose rate,
and for 32 MeV electrons changes by a factor of 1.4
as the nominal dose rate at 1 m changes from 100
rads/min to 400 rads/min. The variation of the
calibration with field size was measured by ionization dosimetry and is unexpectedly large especially
for low-energy electrons. It appears that the
variation can be attributed largely to electrons
which are scattered back into the monitor chamber
from the jaws of the collimator.
15:15
BC5
Preliminary Measurements on a Therac 20
Medical Linear Accelerator. M.S. PATTERSON, P.C.
SHRAGGE, Ontario Cancer Foundation Kingston Clinic,
and G. Van Dyk, Atomic Energy of Canada Ltd., Ottawa.
— W e will first describe the general characteristics of
the accelerator and then present some measured beam
data. These will include depth-dose, flatness and
isodose curves for photon and electron modes. Parameters necessary for treatment planning using the TP11 system will be presented. General machine performance and stability will also be discussed.
H.H. Rossi, R a d i a t i o n Research 71 (1977) 1-8
16:00
BC8
Queen's-Carleton Gajnma Cameras and Positron
Emission Imaging* R.J. DOUGLAS, Queen's University—
The gamma ray detectors that are being developed for
the Queen's electron momentum spectrometer are based
on the high-density-converter/multiwire proportional
counter design of Jeavons
The properties of these
detectors will be presented, and their advantages and
disadvantages for use in positron emission imaging
will be discussed.
*A.P. Jeavons et al, IEEE Transactions on Nuclear
Science Vol. NS-25 p. l6U (1978).
*Supported by NRC.
16:15
BC9
Measurement of a 23B Pu-Li Neutron Spectrum H. ING and W.G. CROSS, Chalk River Nucl. Labs. AECL —
Radioactive neutron sources using the Li(ct,n) reaction
are of interest because they provide lower energy neutrons than conventional Be(a,n) sources. Recently,
238
Pu-Li sources have become available and are used in
assaying for fissile materials in connection with
nuclear safeguards and inventory management. Since
there are no published data on the spectrum of neutrons
from 238 Pu-Li sources, we have measured it to provide
data for neutron transport and dosimetric calculations.
Four spherical proportional counters with different
hydrogenous gas fillings were used to span the energy
range of interest. The unfolded neutron spectrum wa^
"softer" than expected on the basis of a calculation
for an 2l,1Am-Li source. The differences can be
attributed to the presence of oxygen in Pu °2' t*ie alP^a
energy degredation in the PuO^ clusters and neutron
interactions in the LiH medium. From the measured
spectrum, we derived an average energy of 0.5 MeV and a
fluence to kerma conversion factor of 1.44 nrad'em2/
neutron.
I r . W . Geiger and L. Van Der Zwan, Health Phys.
(1971) 120
12
NUCLEI:
MONDAY, JUNE 1 2 . 1 9 7 8
ROOM 3 0 2 2
Chairman:
R.G. Summers-Gill
13:30
BD1
A Measurement of the Panofsky Ratio in 3He.*
F. CORRIVEAU, M.D. HASINOFF, D.F. MEASDAY and M. SALOMON,
Univ. of B.C., J-M. POUTISSOU, Univ. de Montréal. - The
Panofsky ratio in 3 He, P 3 = u(n"+3He^°+T)/u(n"+3He-tr+T) .
has been used to test both the impulse approximation (IA)
and the soft-pion partial conservation of axial-vector
current (PCAC) in nuclei. The IA calculations for P 3
range from 2.51 - 2.98 depending on the amount of the D
state in the 3N wave functions, whereas the PCAC calculations give P3 = 2.1. There have been two previous
measurements of P3: one at 2.28 ± 0.18 agrees quite well
with the PCAC calculation; the other at 2.68 ± 0.13
agrees with the IA result. We have used a large Nal
detector (46 cmif x 51 cm) to detect the high energy
gammas following ir~ capture by 3He. A 30 MeV TT~ beam
was degraded and stopped in a 1.3 cm thick liquid 3He
target. The energy resolution of the Nal was ^4.5% at
135 MeV which produced good separation between the
radiative break-up channels (ynd + ynnp) and the peak of
interest (yT). Our result for P 3 is 2.83 ± 0.07 which
agrees with the higher of the earlier measurements and
indicates that the PCAC calculations are presently incorrect .
A<90
14:15
BD4
Polarisation dans la réaction 1''Nt3He,p)160.
R. ROY, C. RI0UX, R. PIGEON, S.S. DA5GUPTA et R.J. SLOBODRIAN, Univ. Laval.—La polarisation des protons dans
la reaction 14 N( 3 He,J) a été mesurée pour la première
fois à l'aide de l'installation de polarimétrie de
l'accélérateur Van de Graaff, à 9-8 MeV au centre d'une
cible gazeuse d'azote. Les sections efficaces de cette
réaction ont été étudiées précédemnent dans la région
de 10 MeV1. Deux ensembles de facteurs ^jectroscopiques
avaient été utilisés pour un calcul de transfert direct
dans le contexte de la théorie des ondes distordues,
l'un basé sur les calculs de Cohen et Kurath2, l'autre
du à Zuker, Buck et McGrory3. Les sections efficaces,
néanmoins ne distinguaient pas clairement entre ces
deux ensembles. Nos mesures de polarisation favorisent assez clairement le premier ensemble.
'O.M. Bilaniuk, H.T. Fortune, J.D. Garrett, R. Middleton, W.P. Alford, Nucl. Phys. A180 (1972) 690.
J. Cohen and D. Kurath, Nucl. Phys. Alltl (1970) IU5.
3
A.P. Zuker, B. Buck and J. B. McGrory, Phys. Rev.
Lett. 21_ (1968I 39.
2
•Supported by the National Research Council of Canada.
13:45
BD2 Comparison of,the .Direct Rsacli£2na12C(p,cQ,Eft^s.
and '2C(p,q'M9Bp.q..
W.R. FALK, S. DATTA, R. ABEGG,
5. ÀB0U-ZEÏD andS.P. KWAN, Univ. of Manitoba—Measure12
ments of the reaction C(p,a")9B„
, in which the aparticle is emitted in its 20.1 MeV. - 0 + excited state,
have been made at a proton bombarding energy of
MeV.
The a -particles were detected by measuring in coincidence the proton-triton breakup products of this
excited state. A counter system comprised of a position sensitive detector and a AE-E telescope was used
for detecting the protons and tritons respectively.
The overall detection efficiency was about 1%. Cross
section measurements have been obtained at several
angles for 0 > 20°. Finite-range DWBA calculations
using a microscopic formulation of the (p,a) and
(p,a ) reactions will be presented. Comparisons of
these reactions provides a good test of the reaction
mechanism, when examined from the microscopic formulation of three-nucleon transfer.
14:30
BD5
A Study of the l|2Cu(p,y)''3Sc Reaction,
G. U. DIN, McMaster Univ.—Approximately 100 resonances
have been identified in the range 2.00<Ep<2.75 MeV. The
decay schemes for the nine resonances have been investigated using high resolution Ge(Li) detectors. Fiftytwo bound levels up to an excitation energy of 4.47 MeV
were observed out of which seventeen new levels have
been identified. In addition, new results or results
differing from earlier reports have been obtained for
the decay properties of many levels. A strong Ml
(analogue to anti-analogue) transition from the resonance at E p = 2.643 MeV to the bound level at 1.931 MeV
(9/2+) was observed. The spin and parity assignments
were made: 9/2+ at 7.514, 7/2+ at 4.371, _> 7/2 at A.038
and 7/2 at 3.808 MeV. The resonance level at 7.51-4 MeV
has possibly a T=;3/2 character.
Supported by the National Research Council of Canada.
14:00
BD3
E l e c t r o e x c i t a t i o n o f Giant Resonances i n 1 5 N . *
J . ANSALD0, J . C. BERGSTR0M and R. YEN, Saskatchewan
A c c e l e r a t o r L a b o r a t o r y , U n i v e r s i t y o f Saskatchewan,
Saskatoon--The 14-30 MeV e x c i t a t i o n energy region o f
lb
N has been i n v e s t i g a t e d by e l e c t r o n s c a t t e r i n g i n a
momentum t r a n s f e r range 0.36-1.25 f m " 1 . The data has
been analysed i n terms o f C l , El (GDR) and C2 compone n t s . The GDR c o n s i s t s o f two main peaks a t 22 and
25.5 MeV, w i t h s t r u c t u r e around 20 MeV and considerable
El s t r e n g t h t h r o u g h o u t .
The data from 14 t o
19 MeV
i s c o n s i s t e n t w i t h a C2-C1 s u p e r p o s i t i o n .
The C2
s t r e n g t h i n t h i s region amounts t o 22% o f the i s o s c a l a r
energy-weighted sum r u l e , w h i l e the C2 s t r e n g t h from
19 t o 30 MeV appears n e g l i g i b l e .
The assumptions made
i n the a n a l y s i s and a comparison o f the present r e s u l t s
t o r a d i a t i v e capture experiments w i l l be discussed.
'Supported by the N a t i o n a l Research Council o f Canada.
14:45
BD6
Mean Lifetime Correction for PSAM in the
Nuclear Stopping Region.* B. M. LATTA, Queen's Univ.—
An atomic interaction potential which has been proposed
for use in solids1 has been employed to estimate mean
lifetimes by the DSA method. Monte Carlo results for
Cu slowing in Ni and Ar slowing in Au both indicate
that the true mean lifetime will be 25±5 percent longer
than the value which is predicted when the LSS stopping
cross sections are used in the Blaugrund formalism.
These predictions are in agreement with the experimental data of Cooke et al.2 The different potentials
and the different methods of evaluation contribute
approximately equally to this correction.
'B. M. Latta and P. J. Scanlon, Phys. Rev. A10, 1638
(1974).
2
B. E. Cooke, J. R. Leslie, W. McLatchie and B. C.
Robertson, J. Phys. G: Nucl. Phys. 2, 391 (1976).
•Supported by the National Research Council of Canada.
13
15:00
BD7
Lifetimes of Low-Lying States In 5 1 Mn.
J. R. LESLIE, W. McLATCHIE, and P. SKENSVED,
Queen's Univ.—The electromagnetic decay properties of
the low lying states of 5'Mn populated in the
50
Cr(p,y) Mn reaction have been studied at proton
energies (lab) of 1451 and 1600 keV. Lifetimes of the
states of 5 1 Mn at excitation energies of 1825, 2140 and
2416 keV have been determined from measurements of the
Doppler Shift Attenuation Factors of the y-rays deexciting these states. Preliminary values of lifetime
+6
+6
+4
for these three states are 23_^ fs, 22_^ fs and
fs
16:00
63
BD10
Nuclear Spectroscopy of
Zn, P. METFORD,
T. TAYLOR and J. A. CAMERON, McMaster Univ.—Negative
parity states up to 2 MeV and high spin, positive parity
states up to 5.3 MeV in 6 3 Zn have been identified using
gamma-ray spectroscopy following the reactions
Cu(p,n), 6°Ni(a,n) and 5 "Fe( 12 C,2pn). Singles angular distributions and gamma-gamma coincidences were
used to place the many transitions observed. Neutron
pick-up was also studied in the 61*Zn(?,d) reaction using
a polarized proton beam. Transfer J n and j n values and
spectroscopic factors have been assigned for levels up
to 1.5 MeV.
respectively. Mixing ratios have been determined from
an analysis of the measured angular distributions of
y-rays. The results of the present work will be compared with the results of model calculations.
*Work supported by the National Research Council of
Canada.
^Visiting scientist from Dept. of Physics, Manchester
Univ., U.K.
15:30
BD8
V e c t o r A n a l y z i n g P o w e r s of (d,p)
R e a c t i o n s on F v e n - F v o n l f - 2 p S h e l l Nuclei.
T . T A Y L O R , J.a". C A M E R O N and P . G . I K O S S I ,
Monaster Univ. The reactions
b4cr,b4,b»re,5erji (3,p)55Cr,55,59Fe,59Mi i i a v c
b e e n s t u d i e d u s i n g b e a m s of 10 M e V d e u t e r o n n
from the M c M a s t e r L a m b s h i f t p o l a r i z e d ion
s o u r c e and t a n d e m Van de G r a a f f a c c e l e r a t o r .
P.eactions p r o t o n s w e r e d e t e c t e d s i m u l t a n e o u s ly on the l e f t and on the r i g h t of the b e a m
d i r e c t i o n w i t h an array of e i g h t S i ( L i )
detectors.
A n g u l a r d i s t r i b u t i o n s of the
d i f f e r e n t i a l c r o s s - s e c t i o n s and v e c t o r
a n a l y z i n g p o w e r s w e r e m e a s u r e d in 5° i n c r e m e n t s b e t w e e n l a b o r a t o r y a n g l e s of 2 0 ° and
80°.
A DWBA analysis generates qualitatively good fits for s t a t e s o f k n o w n spin so that
p r e v i o u s l y u n k n o w n s p i n s can b e assigned w i t h
reasonable confidence.
15:45
BD9
Stellar Reaction Rates for the 58 Ni(p,y) 59 Cu
Reaction.* C.W. CHENG and J.D. KING, Univ. of Toron to.The cross section and stellar reaction rates for the
58
Ni(p,y) 5 9 Cu reaction have been measured recently by
thick-target^ and thin-target^ techniques and systematic
differences noted and ascribed to the difference in target conditions.2 However, different methods of counting
the number of radioactive 5 9 Cu nuclei produced by proton
capture were employed in the two experiments. We have
measured the cross section for this reaction using both
the thin target and the thick target method, but have
employed the same counting procedure in both cases.
Results will be presented as well as an appraisal of
the thin- vs thick-target technique for determining
stellar reaction rates.
N.A. Roughton et al, Astrophys. J. 205, 302 (1976).
2
T.H. Hall et al., Can. J. Phys. 53, 445 (1975).
*
Supported in part by the National Research Council.
16:15
BD11
Investigation of the Reorientation Effect In
j^Se. R. LECOMTE, S. LANDSBERGER, P. PARADIS and
S. MONARO, Laboratoire de Physique Nucléaire, Université
de Montréal. —
The measurement of the static quadrupole
moment of the first 2 + excited state in
Se was carried
out employing the reorientation effect in Coulomb
excitation. The results are:
B(E2;0+-2+) = 0.388 ± 0.006 e 2 b 2 and
-0.36 ± 0.07 eb. This measurement completes the
02
study of the even selenium isotopes
and confirms
a "prolate" deformation for all these nuclei, in
disagreement with some theoretical predictions2'.
Lecomte and al., Nucl. Phys. A284 (1977), 123.
2
>D. Ardouin and al., Phys. Rev. C12 (1975), 1745.
14
ARCS, CHOCS, PLASMAS R-F ET DYNAMIQUES
MONDAY, JUNE 1 2 , 1 9 7 8
ROOM 2 0 2 4
C h a i r m a n : F.R. McCourt
13:30
Theory an d Performance of an RF Plasma
BEI
Source (SURFATRON) using Surface Wave Propagat ion . M. MOISAN, Z. ZAKRZEWSKI* and R. PANTEL.
Physique, Univ. de Montréal, H3C 3J7.
Long
plasma columns, in many instances preferable
to the positive co lumns of DC discharges, can
be obtalined by means of RF energy.
The plasma
is prod uced by the RF electric field of a surface wave propagating along the column ( * ) •
The wave-launching structure, called a surfatron, i s a small-s:ize device located on the
outside of the die.lectric tube containing the
The surfatron is described and analyplasma.
sed in terms of an equivalent circuit theory.
nes
for its operation and design are
Guide 1i
g iven.
(1)
Z. Zakrzewski, M. Moisan, V.M. Glaude,
C. Beaudry and P. Leprince, Plasma Physics
19, 77 (1977)
* Polish Academy of
Sciences.
14:15
Plasma Properties of Shock-Heated Atomic Beams*
BE4
B.EVANS,JEN-SHIH CHANG,K.TESHIMA and R.M.H0BS0N,Physics
Dept..York Univ. - Neutral beam and plasma properties of
shock-heated atomic beams generated from the reflected
region and expanded through a nozzle system, have been
studied experimentally by electrostatic probes and a
mass spectrometer. The experimental range of the present
work covers incident shock Mach numbers from 3 to 10,
covering a reflected shock temperature range from 2,500
to 25,000°K and leading to beam velocities from 1.5 to
5 km/sec and plasma densities from 108 to 10 10 cm" 3 . Experimental results show that a) the absolute plasma
density inside the atomic beam is one order of magnitude
higher than that of the theory of Jones1.
This discrepancy may be due to the inadequate analysis of plasma
transportation in the skimmer and the collimator. Theoretical estimates of the plasma density for the above
regions have been presented; b) the radial plasma density profile shows the existence of a radial density distribution for the atomic beam maximizing in the center
region of the collimator. The size and density of this
dense atomic beam are discussed.
1
Jones,T.V. .inProc.of 7th A.G.A.R.D. Colloq.on "Recent
Advances in Aerothermochemistry,"Ed.I.Glassman (1966).
*Work supported by the National Research Council °f Cda.
13:45
BE2
A New Microwave Plasma at Atmospheric
Pressure.
J. HUBERT, M. MOISAN and A. RICARD*
Chimie, Univ. de Montréal, H3C 3J7.
Plasma at atmospheric pressure can be obtained
by surface wave propagation with a surfatron.
If an argon plasma is produced within a quartz
tube, it is constricted to a diameter of approximately one or two millimeters but its
length can attain some tens of centimeters
with microwave power as low as 100 watts.
This plasma is quite uniform along the axis,
with a typical electron density of 2 x 10^4
per cubic centimeter.
Since the excitation
and gas temperatures are lower than 4000 K,
the plasma is far from local thermodynamic
equilibrium.
High stability and repeatability is achieved with an argon flow of 0.2 to 17
litres per minute.
Applications are foreseen
in the field of optical spectroscopy and plasma chemistry.
*Labo. Physique des Plasmas,
91405 Orsay, FRANCE.
Bt-212,
14:00
BE3
Plasma Confinement by a Cold Gas Blanket. W.
LIESE, B. AHLBORN and B. ARMSTRONG, Univ. of British
Columbia — It appears possible to completely eliminate
the particle end losses from a linear magnetic fusion
plasma by a cold gas end plug, in which an ablation
fron mechanism is initiated. The essential parameters
for this stopping mechanism are the heat loss W from
the plasma and the gas density p.,. In order to test
this mechanism an experiment is under way in which we
study the behaviour of a low temperature plasma of a
heat wave retained by a cold gas plug. p. and W are
measured and the stopping properties as received from
time resolved photographic and spectroscopic diagnostics are compared with calculated values.
14:30
BE5
The Triple Probe Method for Direct Display of
Plasma Parameters in a Supersonic Flowing Continlum
Plasma.* G.L.OGRAM, JEN-SHIH CHANG and R.M.HOBSON,York
Univ.- The triple probe is a useful method in the analysis of transient and unreproducible plasma phenomena as
no voltage sweep is required. The method also does not
require the use of a large reference electrode which may
disturb the plasma. The calibration of electrostatic
triple probe current and voltage response V12 ins supersonic continuum plasma has been carried out using a low
pressure shock tube. The electron temperature T c and
charge number density N e are related to probe voltage
and current response respectively, fora useful range of
plasma parameters (l£Rp/XD£l0,2<M<6 and 7<<t>n<35 where
Rp is probe radius, X D is the Debye length, M is the
shock Mach number and <f> j 3 is the nondimensional probe
voltage). Experimental results show that: a) within the
range of parameters covered, the electron temperature
may be given by an expression eVu/kT e » A(V[2/Vi 3)-01
to an accuracy of about ± 10%, where A and a are functions of Rp/Ap; b) for Rp/X £10, the present results
agree well with the ideal triple probe theory; c) for
tl3>30 no significant effect of V[3 on plasma density
measurement exists.
*Work supported by National Research Council of Canada
15:00
BE6
Mesure interférométrique de la décroissance
d'une perturbation générée par une étincelle dans l'air,
JAROSLAV P. NOVAK, MAGDI M. SH0UCRI et Z0LTAN SZILI,
direction Sciences de base, Institut de recherche de
1'Hydro-Québec, Varennes, Québec, Canada JOL 2P0 —
Le développement spatio-temporel de longue durée d'un
gaz chauffé par une étincelle a été étudié par l'interférométrie utilisant un laser ultraviolet. L'expérience
utilise un laser à azote TEA opérant à une longueur
d'onde de 3371 8. Lorsque l'énergie injectée est comprise entre 0.05 J et 0.9 J, on observe que la pression
approche sa valeur d'équilibre dans une période de prés
de 30 ps. Le diamètre initial de la région du gaz chaud
varie de 4 à 10 mm selon l'énergie, et augmente approximativement de 50% entre 30 psec et 3 msec. Le résultat
des mesures expérimentales est en bon accord avec les
résultats obtenus à partir de la solution numérique de
l'équation de diffusion de la chaleur. Ceci indique
que dans la phase initiale qui suit l'étincelle, le refroidissement par diffusion est le procédé dominant.
Le développement d'une turbulence faible a été observé
après 150 us.
11:15
BE7
Parametric Study of a Vortex Stabilized Arc.
L. E. GETTEL and F. L. CURZON, Univ. of British Columb i a . — A parametric study of a high current, vortex stabilized alternating current arc operating in argon, has
been conducted. The arc has been operated at input
power levels up to 30 Kwatts with currents up to 400 A
RMS. The energy balance of the arc has been determined
for arc chamber pressures up to 3 ATM. The energy balance for a D.C. arc with similar input power levels has
also been determined, and it was found that the radiative efficiency for the A.C. and D.C. arcs are comparable. The dynamics of the A.C. arc column has been
examined using spectroscopic and high speed photographic techniques.
15:30
BE8
Structural Characteristics of a Magnetically
Driven Arc in Air. H.H. MAI, B. JEAN and K. DIMOFF,
INRS-Energie, Université du Québec» C.P. 1020, Varennes
Québec, Canada, JOL 2P0. —
Phase contrast photography
has helped define the spatial boundaries of a refractive change in gas which immediately precedes the visibly luminous region of a subsonic arc. A close correspondence is observed between the shape of this refractive zone and distortions across the interelectrode gap in the leading edge of the luminous arc column.
Conventional high speed images, taken simultaneously
in planes transverse and parallel to the direction of
arc propagation, show that the luminous region extends
across the full width of the electrodes. This suggests
a subsequent simplification in the interpretation of
differential interferograms obtained simultaneously
with the phase contrast and two-directional high speed
photographs. Correlation of the three photographic
methods shows the existence of a thin, transition layer
of condensed gas which is separated from the ensuing
luminous arc region by a zone of intensely turbulent
gas.
*
Supported by Hydro-Québec Contract IREQ-283/77.
15:45
BE9
Stability Analysis for Converging Shock Waves.*
K. FONG and B. AHLBORN, Univ. of British Columbia.—
The velocity of all converging shock waves grows as
the radius decreases. This leads to stability of the
front against radial perturbations. We have developed
a computer code to calculate the propagation of 2-D
converging shock fronts. The code is used to analyse
the stability of such fronts to finite magnitude distortions from cylindrical geometry. Perturbation
parameter are defined and limits of stability are
obtained. The model was tested by comparing with
experimental results and by comparison with an analytical model.
*Supported by the National Research Council.
16:00
BE10
Electrical Power Extraction from Standing
Shock Waves.* B. AHLBORN, J. KWAN, F. SANDERSON, Univ.
of British Columbia.— Any ionizing shock front is
associated with an electric field across the discontinuity. Such an electrical field has been used to
drive a current and extract electrical power out of a
supersonice flow. In order to obtain this current in
the lab frame of reference a standing shock wave was
produced, by imbedding an obstacle into a supersonic
flow. A shock tube was used to generate the supersonic
flow and voltages of the order of 1 Volt were produced.
Current voltage characteristics of the shock diode
have been measured. In parallel experiments we have
established that bow shock diodes can also be operated
and produce voltages in the reaction products of
C^H^-O^ combustions or detonations, which have been
accelerated to supersonic velocities by the help of
Laval nozzles. In these experiments the bow shock
diodes have extracted electrical energy in a temperature regime which so far has been accessible only to
MHD generators.
*Supported by the National Research Council.
16:15
BE11
Low-Frequency Sheath Admittance of a Sphere in
a Collisionless Plasma. J.G. LAFRAMBOISI" and R. GODARD,
Physics Department and Centre for Research in Experimental Space Science, York University, Toronto.—
Exact calculations of the low-frequency sheath admittance of a sphere immersed in a collisionless, stationary, Maxwellian plasma with no magnetic field, are
presented for nondimensional electrode potentials
-25 £ e<J>p/kTe 1 25, ion-to-electron temperature ratios
0 5 T i/T e ^ 1, and electrode radius to Debye length
0 < r p /A D < 200.
16
SPECTROSCOPIC PROPERTIES OF CONDENSED MATTER:
PHONONS, MAGNONS, FERROELECTRICS, NMR
MONDAY, JUNE 12, 1978
ROOM 3026
Chairman:
D. Cheeke
13:30
BF1
NMR Study of NH„LiS0.,.*
A. WATTON, E.C.
REYNHARDT and H.E. PETCH, Univ. of Victoria.—
Ammonium lithium sulphate is ferroelectric at room temperature, and undergoes a phase transition at 11°C.
The nature of the NHt,+ ionic reorientation in this
material has been investigated by proton absorption,
and spin-lattice relaxation time measurements over the
temperature range 77-400K. The relaxation time results
suggest that a further phase transition occurs at about
133K. The small second moment observed suggests a high
degree of rotational freedom for the ion over the whole
temperature range, but the observed Ti minimum of
13.8ms at 115K is too large to be the result of the
simple onset of isotropic rotation. It is found that
the observations are consistent with a model in which
the NH^ + ion undergoes two twofold and one threefold
simultaneous reorientation.
•Supported by the National Research Council of Canada.
13:45
Dielectric Relaxation in Ferroelectric
BF2
TrlRlycine Sulphate. E. PRASAD, Queen's Univ.,
Kingston, Ont.—Dielectric behaviour of ferroelectric
Triglycine Sulphate was investigated in the frequency
range 4 Hz to 100 KHz and two dispersion regions were
recorded in this frequency range. A high frequency
dispersion was attributed to domain wall motion. A
second low frequency dispersion due to electrical
heterogeneity of domain walls was also observed. The
results indicate that electrical parameters of domain
walls are different and show enhancement of polarization when compared to the bulk values.
14:00
BF3
Echos de polarisation dans le TeO,,. AMIR A.
LAKHANI et DAVID CHEEKE, Univ. de Sherbrooke , et HENRY ETTINGER, CRTBT. CNRS. Grenoble . Nous rapportons
l'observation d'échos de polarisation dans la poudre
piézoélectrique TeO^. Nous avons trouvé qu'une rotation du champ électrique de lecture par un angle
par_rapport à l'axe d'écriture donne une variation en
cos
pour l'amplitude de l'écho de mémoire. Les
détails d'une étude numérique à l'ordinateur basée
sur le modèle de réorientation de Melcher et Shirln
sont présentés. On trouve un désaccord net entre ce
modèle et l'expérience, et des explications possibles
de cette divergence seront exposées.
14:15
3F4
Anomalous Lattice Properties of Ammonium
Metaperiodate. S.L. SEGEL, R.J.C. BROWN and R.D.
HEYDING, Queen's Univ.. Kingston, Ont.—The recently
reported anomalous behaviour of ammonium perrhenate have
now been duplicated in WI^IO,,. These properties
include the temperature and pressure dependence of the
iodine quadrupole coupling, the iodine chemical shift,
the unit cell volume, which for both materials is
essentially independent of temperature, and the Raman
spectrum. It is suggested that these anomalous
properties exist in all amnonium scheelites. A discussion of the probable causes of this behaviour will
be given.
14:30
BF5
Spin Waves in Triangular Antlferromagnets•*
J.A. OYEDELE and M.F. COLLINS, McMaster University —
Simple hexagonal magnetic arrays with antiferromagnetic
Heisenberg nearest-neighbour interactions form a
triangular structure at low temperatures. The spin
wave dispersion relations are calculated for this
structure. The presence of a small dipole-dipole
interaction distorts the triangle so that it ceases to
be equiangular.
•Supported by the National Research Council of Canada.
14:45
BF6
Interchain Coupling between Antiferromagnetic
XY Chains and its Effect on the Spin Peierls Phase
Transitions*. Y. LEP1NE and A. CAILLE, Département de
physique. Université de Sherbrooke. The effect of an
Ising interchain coupling oiji the spin Peierls phase
transition of an XY chain is studied. This form
of coupling was chosen because the pseudo fermion formalism can be simply used only in that case. It is
shown that the dispersion relation for the pseudo fermions has the same form as that of the electrons in ^
the usual Peierls transition with interchain coupling
except that the strengh of the coupling depends strongly on the spin states on the separate chains. For an
interchain coupling J smaller than half the band gap
of the pseudo fermions on a single chain, the spin
Peierls transition is always present and the T " 0
state is unperturbed. Variations of the critical
temperature with J are also investigated.
1) BENl.G. and Pincus, P., J.Chem.Phys. 57,3531 (1972)
2) BENI, G., Solid State Comm. 15, 269 (1974)
* Supported by the National Research Council of Canada
15:00
BF7
A Study of the Magnetic Hyperfine Fields at Cd
Impurity Sites in the Heusler Alloy Series,
Ni
Cu Mn Sb, C. C. M. CAMPBELL and J. A. CAMERON,
McMaster Univ.—The Heusler alloys are a series of local
moment ferromagnets, with a magnetic moment of 4 uB per
formula unit, confined to the Mn site. Alloys in the
series Ni
Cu Mn Sb have been prepared for x = 0,
0.25, 0.5, 8.75xand 1.0. Several uCi of radioactive
'•'in were electroplated on to each of the samples.
After induction melting to the magnetic hyperfine fields
at ^^Cd nuclei were measured by the method of timedifferential perturbed angular correlations. The
results of this study will be reported together with a
phenomenological interpretation of the hyperfine fields
at Cd sites in this and other systems.
15:15
BF8
Microwave Transmission by Larmor Waves. D. S.
MONTGOMERY and M. B. WALKER, Univ. of Toronto.—In recent
microwave transmission experiments of Janossy and Monod1,
oscillation of the phase of the transmitted field was
observed, for Cu, far from the CESR. This was attributed
to spin density carried across the foil by weakly scattered electrons, as they underwent Larmor precession in an
external magnetic field. We have applied the Landau Theory
of Fermi Liquids to investigate the effects of exchange
interaction on the period and amplitude of the Larmor waves.
Strong exchange (B UIT>>1) causes large assymetry in the
power spectrum far from CESR, and modifies the period of
the Larmor waves.
Microwave transmission through metals having anisotropic Fermi surfaces was studied. Here it was found
that particular regions of the Fermi surface and, under
certain conditions, open orbits, give the dominant contributions to the transmitted spin density.
'A. Janossy and P. Monod, Phys. Rev. Letters 37^, 612 (1976).
17
15:30
BF9
Deuterium Spectral Splittings and Spin-lattice
Relaxation Times in the Nematoqen p-methoxy-d3-benzylidene-d]-p-n-butyl-dg-aniline (MBBA-di))» J, LEWIS,
RONALD Y. DONG, E. TOMCHUK and E. BOCK+, University of
Winnipeg — Deuterium FFT spectra were obtained in the
nematic phase of MBBA-djg as a function of temperature
and frequency. These spectra show resolved spectral
lines owing to different conformational average among
the molecular subunits. Orientational order parameters
are determined from the spectral splittings (Av^).
The resolved deuterium spectra allowed selective T[
measurements. While the methyl deuterium Tj's are
found to be very temperature sensitive, the remaining
deuterium Tj's in MBBA-di3 are less so. The deuterium
relaxation mechanisms will be examined in the light of
the observed linear dependence of Ti . on C6v.)2 for
1
the butyl chain.
•Supported by the National Research Council of Canada.
+University of Manitoba
16:00
BF11
Line broadening in SQUID NMR at saturation.
G. LAMARCHF, Univ. of Ottawa.--SQUID NMR is well suited
to study changes in the longitudinal magnetization as a
spin system undergoes resonance. The signal is proportionnai to (MQ - M z ) which tends towards M0 at
resonance as the r.f. power increases to saturation
values. Also as we approach saturation the shape of
the line changes and the line width is observed to
increase. A series of measurements done on Cu metal at
4.2K in fields of 10 to 40 mT, over several order of
magnitudes in r.f. field amplitude will be presented.
Preliminary measurements indicate that the observed
line width increases as \la + bBi" where Bj is the r.f.
amplitude and a and b are constants. The advantages of
SQUID NMR over conventional NMR is at low fields on
systems with long spin-lattice relaxation time and
short dephasing times 1 . 2 . The widening of the lines
under saturation condition limits the usefulness of
c.w. SOUID NMR in observing weak signals.
' n . J. Meredith, G. R. Pickett and 0. G. Svmko,
J. Low Temp. Phys. 13, 607, (1973).
2
15:45
BF
10
Direct Observation of Tunneling Frequencies
by Fourier Transforming the Nuclear Spin Magnetization
Evolution in the Rotating Frame* D. W. NICOLL and
M. M. PINTAR, Phys. Dept., Univ. of Waterloo—An experimental technique is presented with which tunneling
frequencies in the range 10 to 300 KHz in solids are
directly measured. In solids the approach to semiequilibrium of the nuclear spin system in the rotating
frame during a spin-locking pulse sequence exhibits
damped oscillatory behaviour. For HI>>HL, the
frequency of the oscillations of My (t) is 2-yH^ at
exact resonance. In the presence of a set of lattice
states, such as the tunneling-split ground state of
an atomic torsional oscillator CH3 or NH4 in solid
lattices, there are additional frequencies in the
short time evolution of the nuclear polarization.
Transitions between spin-torsional states of different symmetries give rise to the frequencies
2 y H ] ± A I , where the
are the splittings of the
torsional states measured in frequency units.
* Supported by National Research Council
R. A. Webb, Rev. Sci. Instrum. 48, 1585, (1977).
16:15
Pulsed NMR Studies of Aqueous Gels of Wood
Pulp.* A. R. SHARP and M. H. SCHNEIDER, Univ. of New
Brunswick. Pulsed NMR measurements of spin-lattice
(T^), spin-spin (T2) and rotating frame spin-lattice
(T lp ) relaxation times have been carried out as functions of moisture content and temperature for watersulfite pulp mixtures. At moisture contents up to
about 50%, the water molecules are strongly influenced
by the pulp at the interface and are not included in
an ice lattice at temperatures down to at least 190K.
At higher moisture contents, there is a fraction of
the water molecules which is frozen, the freezing
point and magnitude of the fraction both being functions of the moisture content. The relaxation throughout is dominated by proton exchange among the water
protons and the cellulose hydroxyl groups as well as
molecular exchange among the many different possible
sorption sites.
•Supported in part by the National Research Council
of Canada and the U.N.B. Research Fund.
SEMICONDUCTORS AND MOLECULAR CRYSTALS
MONDAY, JUNE 1 2 , 1978
ROOM 3028
Chairman:
D. B r o d i e
13:30
BG1
Electrical Transport Properties of G a ^ A l ^ A s
Alloys. H. J. LEE, L. Y. JURAVEL, J. C. W00LLEY, Univ.
of Ottawa and A. J. SPRINGTHORPE, Bell Northern Research
Measurements of electrical conductivity and Hall coefficient have been made as a function of temperature in
the range 0 - 225°C on epitaxially grown single crystal
n-type samples of Ga
Al As with total carrier concen*
18 -3
tration in the range 1017 _ jo cm" . The experimental
data for the range 0 < x < 0.5 have been compared with
the values predicted by a three conduction band (T,L,X)
model using the standard equations for electron scattering, the energy values of the band minima and the
various deformation potentials and coupling coefficients
being treated as adjustable parameters. For alloys with
0.5 < x < 1.0, only the effects of the X band need be
considered in a similar analysis. Using the values
proposed by Aspnes 1 for GaAs as a starting point, the
variation of the various parameters has been determined
as a function of x. It is found that the L band contribution is significant for 0 < x < 0.4 and that of the
X band in the range 0.2 < x < 1.0.
' D . E. Aspnes, Phys. Rev. B . 14 5331 (1976).
13:45
BG2
F a r - I n f r a r e d C y c l o t r o n R e s o n a n c e in P y r o l y t i c G r a p h i t e . W . F . D A T A R S 7 R . E . D O K Z E M A and
H. SCHABER. T e c h n l s c h e U n i v e r s i t S t MUnchen.
—
C y c l o t r o n r e s o n a n c e h a s b e e n o b s e r v e d in t h e
m a g n e t i c f i e l d d e p e n d e n c e o f t h e r e f l e c t i v i t y of
nyrolytic graphite using circularly-polarized,
f a r - i n f r a r e d l a s e r r a d i a t i o n at w a v e l e n g t h s o f
78 a n d 118 /i w i t h t h e m a g n e t i c f i e l d a n d l a s e r
l i g h t d i r e c t e d a l o n g t h e c - a x i s . F u n d a m e n t a l arri
h a r m o n i c e l e c t r o n r e s o n a n c e s and the fundamental
hole resonance corresponding to masses of 0 . 0 5 8
m D and 0 . 0 4 4 m Q , r e s p e c t i v e l y , w e r e r e s o l v e d .
The electron harmonics possessed structure due
to new types of Landau levels that are caused
by trigonal warping of the Fermi surface near
t h e K - p o i n t (1,2). T h e l e v e l s r e s u l t f r o m leg
and c e n t r a l o r b i t s at e n e r g i e s b e l o w the Fermi
energy. Transitions from the levels provide detailed c o n f i r m a t i o n of the b a n d s t r u c t u r e of
graphite below the Fermi energy.
* Permanent
address:
McMaster University,
Hamilton
I. G . D r e s s e l h a u s , P h y s . R e v . B 10, 3 6 0 2 ( 1 9 7 4 ) .
2. K.IJakao, J . P h y s . S o c . J a p a n 40, 761 (1»76).
15:00
11:30
BG3
Evidence for Mini-gaps in Si Inversion Layers.
AMIR A. LAKHANI, Université de Sherbrooke. — We present experimental evidence for the presence of minigaps on certain non-principal planes of Si. The minigap gives rise to a characteristic structure in the
d.c. conductivity of electrons at low temperatures.
Shubnikov-de-Haas type of oscillations in the conductivity are used to distinguish the contribution to
the electrical transport by carriers in each band.
The effective mass of the electrons in (811) surface
has been measured and found to be strongly dependent
on the carrier density, implying a highly non parabolic band. Magnetic breakdown occured at high magnetic fields (>1T). Estimates of the magnitude of the
mini-gap yield a value of about 4 meV which increases
with the applied gate field. Above results are interpreted in terms of the "Valley Projection Model"
as proposed by L. Sham and M. Nakayama.
14:15
BG4
r.ot Phonon Effects on Ultrafast Carrier
Relaxation in Semiconductors.* H. M. VAN DRIEL, Univ.
of Toronto—The generation of hot, high-density carrier
distributions in semiconductors by short, highintensity laser pulses has been shown to have a profound effect on the optical properties of these
materials. In particular, the alteration of the transmissivity and reflectivity has led to the use of semiconductors in picosecond opto-electronic switching.
The switching time in some cases is strongly influenced
by the rate of carrier energy relaxation which takes
place via phonon emission. The energy relaxation of
hot, high-density carriers, however, leads to nonequilibrium phonon distributions which create a
relaxation bottleneck for the carriers. The influence
of hot phonon distributions on the carrier relaxation
rate will be discussed with respect to recently
obtained data in germanium.
^Research supported by NRC and a Univ. of Toronto
Connaught Grant.
14:30
BG5
On the Carrier Recombination Kinetics in
Intrinsic Germanium.* M. I. GALLANT and H. M.
VVI DRIEL, Univ. of Toronto—Carrier densities of up to
in-°/cc have been produced in single crystals of intrinsic Ge at 300K using a high-intensity Nd:glass
laser. A time-resolved study of the photoluminescence
spectrum has been made to compare the relative importance of indirect versus direct gap recombination processes. Subnanosecond time resolution has enabled us
to demonstrate that the direct gap recombination rate
is two orders of magnitude greater than the indirect
rate and therefore dominates the recombination
kinetics for high carrier densities. The data presented will be interpreted in terms of current models
for radiative and Auger recombination processes.
*Research supported by NRC and a Univ. of Toronto
Connaught Grant.
14:45
BG6
Phonon Broadening of Electron-Hole Droplet
Photoluminescence Line Shapes in Intrinsic Si. J.A.
ROSTWOROWSKI and B. BERGERSEN, Univ. of British
Columbia.-We present a detailed study of the recombination emission of the electron-hole droplet (EHD) in
intrinsic silicon at liquid helium temperatures. To
date, one has used the unresolved TO- and LO-phonon
assisted replicas of the recombination emission to
extract from experiment the chemical potential and the
density of the electron-hole pairs in the drop1 with an
assumed T0-L0 intensity ratio. We have measured the
weaker but resolved TA-phonon assisted replica with an
excellent signal-to-noise ratio. The TA-phonon replica
is found to be narrower - in fact - from the analysis
of the line shape we find a density of 3.0 x 10 1 8
electron-hole pairs/cm3. Our result is approximately
10 percent less than previously reported1. A theoretical examination of the phonon broadening of the spectra is presented and the results used to discuss the
difference in line shapes associated with the TO-LO
and TA replicas.
BG7
Biexcitons in Silicon. M.L.W. THEWALT and J.A.
ROSTWOROWSKI, Univ. of British Columbla.-We observe a
new peak in the photoluminescence spectrum of intrinsic
silicon which we attribute to the recombination of an
electron-hole pair in a biexciton leaving behind a free
exciton. The biexciton line (TA-phonon replica) is
well resolved at liquid helium temperatures. A calculation of the emission line shape based on a simple
model is found in good agreement with experiment. From
the theoretical fit we deduce a binding energy of 1.2
meV and a 'radius' of 100A for the biexciton.
15:15
BG8
Etude de l'alliage I n ^ G a y S b par magnétooptique interbande.* A.P. ROTH** et E. FORTIN, Univ.
d'Ottawa.
La variation spectrale de l'effet photovoltaique d'échantillons polycristallins de Ini_xGaxSb a été observée à 6K en présence de champs magnétiques allant jusqu'à 7 teslas. Les oscillations spectrales dues aux
transitions interbandes entre niveaux de Landau sont
analysées à l'aide d'un modèle de bandes couplées
adapté aux polycristaux. On déduit un ensemble cohérent de paramètres de bandes pour chaque échantillon
et on obtient leur variation à travers l'alliage.
* Subventionné par le CNRC.
** Bénéficiaire d'une bourse d'échanges culturels du
Conseil des Arts du Canada.
15:30
BG9
Bandgap and L a t t i c e Constants o f the Pentenary
Semiconductor System A<»( i _ x ) C u x I n S ; ( i-Y) S e ÇY* G - C H A P M A N
B.K.GARSIDE and J.SHEWCHUN, McMaster Un.—Much i n t e r e s t
has been expressed i n the t e r n a r y I R - I I I - V I , group
semiconductors owing to the wide range o f bandgaps
a v a i l a b l e , and the m a t e r i a l s ' strong o p t i c a l non l i n e arity.
A subset o f these; AglnS-, AgInSe 2 , CuInS-, and
CuInSe,,; have been combined t o form the pentenary
system Agj 1 _ X jCu ) ( InS2j 1 _YjSe 2 Y. With these a l l o y s i t
i s p o s s i b l e t o vary the bandgap w h i l e keeping the
l a t t i c e spacing c o n s t a n t . Samples were prepared by
r e a c t i n g s t o i c h i o m e t r i c powder mixtures a t 600 t o
900 C. Powder X-ray d i f f r a c t o m e t r y t e s t s suggested
the a l l o y s had complete s o l i d s o l u b i l i t y throughout
the system. A c h a l c o p y r i t e type s t r u c t u r e was i n d i cated f o r t h i s pentenary system. From cathodoluminescence s t u d i e s on pressed bars o f these powders the
bandgap energies were estimated a t 77 and 300 K. The
r e s u l t s were i n good agreement w i t h the published data
f o r the t e r n a r y compounds and the C u I n S . , . Y i S e ? v
system. These t e s t s a l s o suggest the
a l l o y s are a l l d i r e c t bandgap semiconductors.
•Supported by the National Research C o u n c i l .
15:45
BG10
!M. F. Gratton and J. C. Woolley, J. Electron. Mat.
455 (1973).
2
•R.B. Hammond, T.C. McGill and J.W. Meyer, Phys. Rev.
B13, 3566 (1976).
Solid Solubility Limits in GaAs^Sbj ^Alloys.
M. F. GRATT0N, R. G. GOODCHILD, L. Y. JURAVEL and
J. C. WOOLLEY, Univ. of Ottawa. — Recent work 1 , 2 appears
to show disagreement as to whether an open solid
solubility gap exists in the system GaAs^Sb^
Measurements have therefore been made to determine the
boundaries of the solid phase fields by annealing
samples to equilibrium at temperatures held constant to
±0.5°C. The results confirm that this system has a
peritectic horizontal at 745 ± 2°C with solubility
limits at x = 0.38 and 0.67. The range of solubility
in GaAs falls rapidly with reduced temperature, the
solubility limits at 700°C being x « 0.31 and 0.95.
T. Waho, S. Ogawa and S. Maruyama, Jap. J. Appl. Phys.
16 1875 (1977).
19
16:00
BG11
Temperature Dependent Electronic Absorption
Spectrum of TCNQ Compounds. C. CARLONE and M. MICHAUD,
Département de physique. Université de Sherbrooke, and
N.K. HOTA and J. ZAUHAR, CMR. St-Jean. Qué.
The absorption spectrum of D-TCNQ (D is potassium, barium calcium and perylene) has been studied between
3100X and 240008 and from 10 K to room-temperature. At
lower temperatures, the transitions sharpened considerably, revealing vibronic structure in the intra-molecular bands. Jhe vibrational quanta in TCNQ are
1300 ± 50cm . In the K, Ba and Ca compounds, the inter-molecular band at 11,000X remained relatively broad
and temperature independent. We have also observed a
weaker broader feature at 8500& for the Ba compound.
In the perylene-TCNQ compounds, we have observed the
TCNQ~ band at approximately 9800$, i.e. this band is
shifted considerably towards the red compared to the
metallic-TCNQ compounds. In the case of perylene
3-TANQ1, we have observed an inter-molecular band at
5100&, i.e. this band is more energetic than its intramolecular band.
16:15
RCl 7
Charge Carrier Generation in Single Crystal
Benzophenone.
J.B. WEBB AND D.F. WILLIAMS,
Div. Chem., National Research Council of Canada.—
The generation of free charge as a function of light
intensity and applied field has been studied in single
crystals of the substituted aromatic hydrocarbon
benzophenone. With 3371A0 excitation, the formation
of free carriers occurs through the interaction of a
free singlet exciton and a singlet exciton trapped at
the surface of the crystal. This results in the
formation of a free electron and trapped hole.
A collected charge strongly dependent on applied field
has also been observed and is accounted for on the
basis of a combined Poole-Frenkel-Weiz-Cobas model.
ANNUAL BUSINESS MEETINGS
MONDAY, JUNE 12, 1978
16:45
Division of Aeronomy and Space Physics
Note:
CHAIRMAN:
Division of Atomic and Molecular Physics
F.M. Kelly
Division of Condensed Matter Physics
W.J.L. Buyers
Division of Medical and Biological Physics
M.H. Repacholi
Division of Nuclear Physics
W. Falk
Division of Optical Physics
J.W.Y. Lit
Division of Particle Physics
J. Hébert
Division of Plasma Physics
C. Richard
Division of Theoretical Physics
B. Goulard
Division of Physics Education Annual Business Meeting, Tuesday, 16:15, Room 2036
MONDAY, JUNE 12, 1978
ROOM 2050
20:00
BH
G. Rostoker
Night Flashes: A Multiple-Image, Multi-Media Show for Science
JEARL WALKER, Cleveland State
UtvLuejulttj
20
TUESDAY, JUNE 13, 1978
ROOM 2024
Chairman: W.D. Westwood
9:00
CA1
SYNCHROTRON RADIATION
Photoelectron Studies of Inorganic Compounds using Synchrotron Radiation
G.M. BANCROFT, The University
of Western
Ontario
Synchrotron radiation provides an intense, tuneable, polarized source in the VUVx-ray region. Using synchrotron radiation from the Wisconsin storage ring as the
photon source, valence band and outermost d core level photoelectron spectra of a
number of solid Sn, In, Sb and Pb compounds have been obtained at photon energies
between 20 eV and 100 eV. With the high instrumental resolutions (0.15 eV to 1 eV),
very narrow core level linewidths have been obtained, and a broadening due to ligand
field splitting has been characterized. Inherent linewidths (0.35 ± 0.02 eV) of
the Pb 5d levels have been obtained by two novel methods - an extrapolation procedure
and yield spectra. The area ratio Pb 5d5/2 : Pb 5dj/2 varies widely with photon
energy and is chemically sensitive. Some of this "fine structure" is probably due to
scattering of photoelectrons from neighbouring atoms (as in EXAFS). Future prospects
for using synchrotron radiation as a narrow photoelectron source will be discussed.
9:30
CA2
EXAFS Investigations of Disordered Systems
D. CROZIER, S-onon Traser
University
The extended fine structure in the X-ray absorption coefficient is dominated by the interference of the photoelectron scattered by atoms in the
immediate neighbourhood of the atom which absorbs the X-ray photon and
thus can provide information concerning the local structure around the
X-ray absorbing atom in ordered or disordered systems. The Extended X-ray
Absorption Fine Structure (EXAFS) technique will be illustrated with
results (!) obtained at the Stanford Synchrotron Radiation Laboratory on
solid and liquid metals, Ga and Hg, amorphous and liquid semiconductors,
Se, Ge, GeSe, and As2Se3, and rare earth salts in aqueous solutions.
Emphasis will be placed on the structural changes observed as a function
of temperature. Recent advances in experimental methods will also be
discussed.
(') Partially supported by grants from the National Science Foundation
of the U.S. and National Research Council of Canada.
; uu
10:00
CA3
Soft X-ray Microscopy/Spectroscopy Applied to Research and Development*
J.Wm. McGOWAN, The University
0(j Western
Ontario
The development of ultra-violet lithography has made possible the rapid advancement in
miniaturization of s^mi-conductgr circuits. Recently it has been demonstrated that the use of soft
x-rays leads to a 10 and to 10 decrease in the microcircuit area. The use of the same soft
x-ray lithographic techniques has also made possible studies to biological and geological samples
at the microscopic level. The development of high resolution x-ray resists and intense tunable soft
x-ray sources, such as the Synchrotron Radiation source, now facilitates microscopic studies
(<100 X) and potentially spectroscopic studies where individual elements within a cell or
geological specimen can be spatially determined. This review will summarize what has and is being
done with the new tool and emphasize in particular the program underway now in Canada.
*
10:30
10:45
CA4
Supported in part by the Medical Research Council of Canada and the U.S. Army.
Break
Synchrotron Radiation - Present Research and Future Development
I . LINDAU, Stanford
University
The use of synchrotron radiation has during the last few years developed into a well established
spectroscopic technique for research within physics, chemistry and biology. A review will be
given of present and planned facilities, instrumental capabilities and future research developments
to utilize the unique properties of synchrotron radiation (continuous spectral distribution from
the infrared to hard x-rays, polarization, collimation, pulsed time-structure). The diversity of
research problems will be illustrated with examples from x-ray absorption, diffraction, scattering,
fluorescence and photoemission as well as with applications within materials science, catalysis,
surface science, lithography and topography. An attempt will be made to single out the research
fields within which synchrotron radiation will have the greatest impact in the near future.
TUESDAY, JUNE 13, 1978
ROOM 2028
Chairman: A. F u l f o r d
9:00
CB1
RADIO STUDIES OF THE IONOSPHERE
Experimental Aspects of Ionospheric Scintillation Observations
G. HARTMANN, Max Planck In&tiXwt
fan. KeAonomle
The propagation of electromagnetic waves through an inhomogeneous, anisotropic atmosphere (e.g. ionosphere)
usually results in variations in the amplitude, phase and angle of arrival of the waves at the receiving
site which is generally located on the ground but may also be aboard a satellite. These variations were
denoted by astronomers as scintillations. There are two principally different methods to investigate the
scintillation producing irregularities in the ionosphere: 1. In situ measurements, 2. Remote sensing
methods. The latter can be subdivided into passive and active measurements. Recent scintillation studies
show that only a combination of radar data, satellite radio beacon data and in situ data can lead to a
significantly better understanding of the complicated physical processes that cause these irregularities in
the ionization of the ionosphere.
9:30
CB2
Characteristics of Radio Signals Randomized by Scattering from Ionospheric Irregularities
K . c . YEH, UniveA&tty
of
lUilnoù,
It is known the ionosphere is frequently permeated by random irregularities in the electron
concentration. Their root-mean-square fluctuations from the mean are usually very small, but they
can rise to 50% or even larger at the magnetic equator as shown by in situ measurements. These
irregularities can scatter radio signals propagating through the ionosphere and consequently
modify the temporal and spatial behavior of such signals. This paper reviews the methods that
have been developed to characterize these signals, and the statistical relations between the signal
and the medium.
10:00
CB3
Doppler and Polarization Measurements of Auroral Backscatter
G.J. S0FK0, ilnlveAAtty
of Saskatchewan
Near Saskatoon, Sask. a 42 MHz CW bistatic auroral scatter system in which the transmitting and
receiving antennas are about 35 km apart has been in operation for some years. The system was
first used to make complete polarization measurements of the scatter, and later to make Doppler
measurements. Current theories of auroral scatter will be discussed in terms of both their ability
and inability to explain the observations.
10:30
10:45
CB4
11:15
CB5
Break
The Effect of Ionospheric Irregularities on Synthetic Aperture Radars
J . K . E . TUNALEY, The UnlveAAiXy of We&teAn OnùvUo
Radio Beacon Studies of the Ionosphere
K. DAVIES, Environmental
Reseanch LaboA.ato/Ue6,
Boulden.,
Colorado
Satellite radio beacons offer a particularly simple method of monitoring
temporal and spatial changes in the ionosphere. Orbiting satellite
beacons give spatial resolution which can be combined with temporal
resolution provided by geostationary beacons to produce contour maps of
columnar electron content of the ionosphere. Such observations give
"snapshots" of the ionosphere that are difficult to obtain in any other
manner. Beacon observations enable observations of a wide range of
ionospheric irrégularités from global scales down to hundreds of meters.
Spaced receiver observations of traveling ionospheric disturbances in
the USA show rather poor correlation indicating the presence of more
than one source. A particular type of modulated Fresnel-type fading is
interpreted in terms of diffraction by a narrow cylinder or sheet of
ionization with transverse size of the order of 200 meters.
22
ELEMENTARY PARTICLES - EXPERIMENTAL
TUESDAY, JUNE 1 3 , 1 9 7 8
Room 3 0 0 6
Chairman:
J . Hébert
9:00
CCI
10:00
10:15
CC2
Proton - Proton Elastic Scattering at Large Momentum Transfer at 200 and 400 GeV
D. STAIRS, MC.GM
UrUvzuiXy
Break
The New Spectroscopy
N. REAY, Ohio StaXz
The Next Step
UrUveiuity
11:15
CC3
Anomalies in Pionlc 3He, G.A. BEER, D.A.BRYMAN,
M.S.DIXIT, S.K.KIM, J.A.MACDONALD, G.R.MASON, A.OLIN,
R.M.PEARCE, U of Victoria, M.KRELL, U. de Sherbrooke,
J.S.VINCENT, TRIUMF, U3C - A recent experiment at
TRIUMF1 has shown that the intensity ratio Kg/Kg for
pionic transitions in liquid 3He is anomalously large,
with a value 1.05±.07. This ratio is to be compared
with a similar value 1.24+.09 for liquid ''He 2 but with
normal values of 0.40±.04 and 0.38±.043 respectively,
for gaseous 3He and "He. Furthermore, the strong
interaction shift observed at TRIUMF for the Is state
of II3He is 27±5 ev compared to 44±5 ev observed elsewhere3 . This discrepancy might be resolved by an
absorption edge technique using a selenium foil.
1
2
3
Mason et al, Phys.Lett (in press)
Backenstoss et_al,Nucl.Phys. A232 (1974) 519-532
Abela et al, Phys.Lett 68B (1977) 429-432
11:45
CC5
Polarization Paramecers in Fren Elastic ileutron
Proton Scattering. * C . J . ORAM, D. A. AXEN, R. DUBOIS,
R. KEELER, G.A. LUDGATE, U.B.C., C. AMSLER, D.V. BUGG,
J.A. EDGINGT0N, R. GIBSON, Queen Mary College,
N.M. STEWART, Bedford College. A. CL0UGH, 0. GIBSON,
Surrey U. , L.P. ROBERTSON, U.Vic. , J.R. RICHARDSON,'
U.C.L.A. - The Wolfenstein parameter D t in free n-p
scattering has been measured to an accuracy of ±0.06 at
210, 325, 425 and 495 MeV in the center of mass angular
range 60° to 160°. The polarization parameter P n p was
measured simultaneously to an accuracy of ±0.015. The
polarized neutron beam is obtained by polarization
transfer on deuterium using the TRIUMF polarized proton
beam. The polarization of the recoil proton, from free
n-p scattering, was analyzed using a carbon polarimeter.
The new measurements were incorporated with the previous
world data and an energy dependent phase shift analysis
performed at each of the above energies. A marked
improvement in the 1-0 phase shifts was obtained.
* Supported by the N.R.C.
11:30
cc4
Variation of Pionic X-Ray Intensity with Atomic
Number,G.A.BEER,M.S.DIXIT,J.A.MACDONAIDft.R.MASON,A.OLIN,
R.M.PEARCE, U.of Victoria, C•SABEV.CERN,W.C.SPERRY,Cen•
Washington U.C.WIEGAND,Berkeley - The X-ray intensities
in mesic atoms are not yet completely understood. In the
case of kaons.the intensities of kaon X rays per stop
have been observed1 to vary with Z in a way similar to
the periodic table. We have measured pionic X-rays in
the range 10 kev to 500 kev for 57 elements. Typically
two or more transitions with principal quantum numbers
between 1 and 11 were seen for each element. The targets
were packaged in elemental form in 10 cm diameter discs,
some with thin mylar windows. The discs were mounted, 8
at a time,in a remote controlled target wheel which was
situated in the 100 MeV/c IT beam of TRIUMF. X-rays
were detected in a hyperpure GE detector gated by a stop
signal from a scintillator telescope. The X-ray yields
have been corrected for counting system dead time, for
detector efficiency variations,and for self absorption
in the 2 gm/cm2 target. Statistical uncertainties are
typically less than 5%. Preliminary results will be presented for the 6-5 transition which was observed for
30JZS75.
'.G.L.Godfrey and C.Wiegand, Phys Lett. 56B (1975) 255.
23
TUESDAY, JUNE 1 3 , 1 9 7 8
ROOM 3 0 2 2
Chairman:
D.M. S h e p p a r d
9:00
CD1
Levels
9 7„
Tc.
S. LANDSBERCER, R. LECOMTE, P. PARADIS and S.MONARO,
Laboratoire de Physique Nucléaire, Université de
Man tréal. —
The level structure of y / Tc was investigated by the ^^Mo(p,ny) reaction at proton energy
between 2.3 and 5.2 MeV. Excitation functions extracted from singles y-ray measurements and y-y coincidence data enabled us to solve some discrepancies concerning several excited levels in 97jc a t low energy .
For instance revised from 574.2 keV to 580.1 keV to
580.1 keV. Furthermore the existence of previously
reported levels at 807, 850, 896, 940 and 1173 keV is
not supported by the present data and the y-rays
decaying from (or to) these states could be placed
elsewhere in the level scheme of " i c .
1) J.M. Picone et al., Phys. Rev. C6, 1970 (1972).
9:15
CD2
The Development of a Liquid Argon Polarlmeter
for Fast Neutrons. J. BIRCHALL, J.S.C. MCKEE, W.D.
RAMSAY and N. VIDELA, Cyclotron Laboratory Univ. of
Manitoba—An existing liquid helium neutron polarimeter
has been adapted for use with liquid argon. The scintillations induced in the liquid argon by fast neutrons
have been shown to be adequate to permit use of an
associated particle system for reducing background.
When used with moderate shielding of the detector a
clean scattering experiment can be performed. Preliminary data are presented.
NUCLEI:
been c a r r i e d o u t .
In the case o f e l e c t r o n s
t h e c o m p u t e d r e s p o n s e f u n c t i o n s have been
compared t o e x p e r i m e n t a l d a t a .
Various
p a r a m a t e r i z a t i o n s of the response f u n c t i o n s
have been u s e d i n c o n v o l u t i o n s and d e c o n v o l u t i o n s of beta s p e c t r a .
The a c c u r a c y
and u n i v e r s a l i t y o f p r o c e d u r e s i n d e c o n v o l u t i n g e x p e r i m e n t a l d a t a w i l l be
discussed.
•Supported
^On leave of absence at Queen's Univ., Kingston, Canada.
t+Present address: U.K.A.E.A., Risley, Warrington, U.K.
t++p r e s e n t address: Dept. of Medical Biophysics,
Manchester Univ., U.K.
ttt+Present address: Nuclear Physics Division, A.E.R.E,
Harwell, U.K.
9:45
CD4
A Monte C a r l o C a l c u l a t i o n f o r
E l e c t r o n and P o s i t r o n R e s p o n s e F u n c t i o n s i n
Ge D e t e c t o r s . *
B. VARLEY, J . E . K I T C H I N G , W.
LEO, J . M I S K I N and R . B . MOORE, M c G i l l
Univ.-In o r d e r t o t e s t t h e accuracy of the data
h a n d l i n g p r o c e d u r e s used t o e x t r a c t endp o i n t s , shape f a c t o r s and b r a n c h i n g r a t i o s
using the McGill superconducting beta s p e c t r o m e t e r , a g e n e r a l Monte C a r l o c a l c u l a t i o n f o r
e l e c t r o n a n d p o s i t r o n r e s p o n s e f u n c t i o n s has
by
N.R.C.
10:15
CD5
K
CHEUN G, H. HUANG
Dec ay o f 122ln.*
a nd J . K . P . LEE, M c G i l l U n i v - - T h e d e c a y o f
1 2 2 i n has b een s t u d i e d u s i n g s o u r c es o b t a i n ed
f r o m t h e Mc G i l 1 o n - 1 i ne mass s pec t r o m e t e r and
f r o m 1 2 4 S n ( d , a ) r e a c t ion via i n t e r n a l de u t e r o n
beam bomba r dment s .
T he on - 1 i ne ma s s s pec t r o me t e r has a 2 3 8 y t a r g e t and a s u r f a c e i o n i za t i o n sou r c e. 1 22 I n f r om f i s s i o n i n d u c e d
by t h e 100 MeV p r o t o n beams w e r e e x t r a c t ed
manua 1 1 y and c o u n t i n g u s u a l 1 y s t a r t s
a bout
20 se c a f t e r t h e e x t r a c t i o n ,
Comp a r i son
of
t h e y r a y s f r o m t h e t wo s o u r c e s an d t h e i r
d e c a y c h a r a c t e r i sties shows t h e ex i s t e n c e o f
t w o i s o m e r s o f h a 1 f - 1i ves 10 . 8 - 0 4 s a nd
1 0 . 3 t 0.6 s •
Y -Y co i n c i d e nce mea s u r e m e
nts
w e r e p e r f o r med a nd se pa r a t e d e c a y se heme s
w e r e o b t a i n ed su
i n g p a r e n t J o f 8 " and
(3+,4 + ,5+)
The T i l l - t i m e o f t h e first 7"
s t a t e wa s m e a s u r ed t o be 7 . 2 » 1 . 0 u s e e ,
Re s u 1t s a r e comp a r e d t o a BC S p r e d i c t i o n
•Supported
9:30
CD3
Neutron Orbit Sizes in the Isotopes of Tin. R.
CHAPMAN+, M. HYLAND t+ , J. L. DURELL, J. N. MO, M.
MacPHAILt+, H. SHARMA +++ , and N. H. MERRILL t+++ , Dept.
of Physics, Manchester Univ., U.K.—Root-mean-square
radii of 3Si, , 2d3, , lg7, , and lhii. neutron orbits in
k
a
n
/2
the isotopes of tin with A = 113, 115, 117, 118, 119
and 120 have been determined from a DWBA analysis of
cross section data from the sub-Coulomb (t ,d) reaction.
The differential cross sections for the (t,d) reaction
were measured at laboratory angles in the range from
120° to 160° for triton energies in the range from
4.25 MeV to 5.75 MeV. Spectroscopic factors of the
populated states were obtained from a sum-rule analysis
of published neutron stripping and pickup data on the
isotopes of tin. The behaviour of neutron orbit size
within the isotopic sequence of final nuclei will be
discussed.
A>90 AND NUCLEAR INSTRUMENTATION
by
N.R.C.
10:30
CD6
Studies of the
Xe and 1 2 3 X e L e v e l
Struct ure.*
J . E . CRAWFO RD, A. K0GAN, K.
SOFIA and B . N . SUBBA RAO , McGi 11 Uni v . - - The
n e u t r o n d e f i c i e n t i so t o p es 1 2 4 , I :: 3 c s have
been p r o d u c e d i n ( p , n ) a nd ( p , 2 n )
reactions
u s i n g t h e p r o t o n beam o f t h e McGi11 s y n c h r o ( S , -, ) s p e c t ro s c o p y on t h e d e c a y
eye 1 o t r o n .
124CS-* 1 2 4 x e y i e l d s a 1ev e l scheme w h i c h
d i f f e r s i n sorie r e s p e c t s f r o m t h a t o f D r o s t e
et al . 1).
P r e v i o u s l y un r e p o r t e d l e v e l s a t
1 6 2 7 . 3 and 2 3 7 2 . 0 keV ha ve been a s s i g n e d ,
and t h e r e s u l t s o f c u r r e n t a n g u l a r
c o r r e l a t i o n e x p e r i m e n t s w i l l be p r e s e n t e d .
The 12 3 C s d e c a y i s c u r r en t l y b e i n g s t u d i e d .
1
*
) c h . D r o s t e , L . G o e t t i g , T. M o r e k , J .
S r e b r n y , J . B u c k a , J . D o b a c z e w s k i and
S . G . R o h o z i n s k i , Z. P h y s . A284 , 297 ( 1 978 )
Supported
by
N.R.C.
10:45
I(n,2n)
I As A Fast-Neutron
CD7
The Reaction
Flux Monitor. D.C. Santry, AECL, Chalk River Nuclear
Labs•—The feasibility of using iodine as a fastneutron monitor was studied by measuring the production
of 13 day 1 2 6 i activity as a function of neutron energy.
Monoenergetic neutrons were produced with a tandem
Van de Graaff accelerator with the reactions D(d,n)3He
and K d . n ^ H e . Cross sections were determined from a
threshold energy of 9.2 MeV up to 20 MeV relative to
the known cross sections for the 32 S(n,p) 32 P and
2I+
Mg(n,p) 2<4Na reactions. The study confirmed that the
cross section and decay characteristics for 1 2 6 i make
it suitable for measuring the high energy neutron
component in nuclear reactors and at accelerators.
24
11:00
CD8
The Extended Thomas-Fermi Density Matrix*.B.K.
JENNINGS,SUNYtStony Brook.New York.
The extended Thomas-Fermi model is used to obtain an
expression for the off-diagonal density matrix.The result is found to differ sligtly from the DME .The
approximations are discussed in terms of the Wigner
distribution function and future improvements sujigt^ted.
11:30
CD10
A Study of a Three-Quasiparticle Isomer In
175
Ta. A. LARABEE, L. BUJA-BIJUNAS and J. C. WADDINGTON
McMaster Univ.—Previous work done on 175 Ta has located
a high-spin isomer at 1567.9 keV.D This isomer was
reported to have a half-life of approximately 200 ns
and was found to decay via the 9/2~[514] band. No
information was given concerning the rotational band
above this isomer. Experiments at McMaster University
using the 1 6 8 Er( u B,4n)1 7 5 Ta reaction have been done
in order to study the energy levels feeding this isomer. The isomer was found to be longer lived than
previously reported with a half-life of 3.0 + 0.4 us.
Delayed and prompt y-y techniques were used to isolate
the y-rays feeding and de-exciting this isomer. The
previously reported life-time^ may possibly be attributed to the decay of the 131.6 keV level.
*J.W.NEGELE and P.VALTHERIN,Phys.Rev.Ç5, 1472(1972).
*Supported in part by the National Research Council of
Canada
1)
C. Foin, Th. Lindblad, B. Skanberg and H. Rvoe,
Nuclear Physics A195, 465 (1972)
11:45
CDU
11:15
CD9
Low-Ly i n g S t r u c t u r e of 1 2®Ba.*
P.
BRODEUR, S . K . MARK a n d B .P PATHA K, M c G i l l
U n i v . - - L o w - 1 y i ng s t a t e s o f 129Ba a r e
] 2 g
i n v e s t i g a t e d t h r o u g h t h e b e t a de c a y o f
La,
w h i c h i s p r o d u c e d by t h e ( p , 2 n
i n 130Ba.
The d e c a y i s s t u d i e d by means o f b e t a , gamma
and c o n v e r s i o n e l e c t r o n s p e c t r o s c o p y
techniques.
T he h a l f - l i f e o f 12 9La i s
m e a s u r e d t o be 1 1 . 6 ± 0 . 2 min. Ma ny
t r a n s i t i o n s a r e o b s e r v e d and a 1 e v e l scheme
c o m p r i s i n g mor e t h a n 38 s t a t e s i s
constructed.
The t o t a l d e c a y en e r g y i s
m e a s u r e d and c o m p a r e d wi t h t h e p r e d i c t i o n s o f
mass f o r m u l a e ,
S p i n and p a r i t y a s s i g n m e n t s
a r e d e d u c e d f r om d e c a y p r o p e r t i es .
The
s t r u c t u r e of
29Ba i s d i s c u s s e d w i t h o t h e r
a v a l 1 a b l e i n f or m a t i o n on t h e t r a ns i t i ona1
b e h a v i o u r o f t he n e u t r o n d e f i c i e n t o d d - A Ba
nucl e i .
•Supported
by
Determination of the Static and Transition Quadrupole
moments of .he even-even Ru isotopes.
F. PARADIS, R. Lecomte, S. LANDSBERGER, and S. MONARO,
Laboratoire de Physique Nucléaire, Université de
Montréal. —
Measurements of the Coulomb excitation
probab ilities of the first 2+ states in 100-102-104Ru
have b een made with ^He and 1^0 projectiles, by resolving he elastically and inelastically backward
scatte red particles in four surface barrier detectors
placed
157.5 and 172.5 . The measurements yield
for B( E2;0+-2+) and Q 2 + :
(-0.43 0.10) e.b. ( 1 0 °Ru)
(-0.56 0.10) e.b. ( 1 0 2 RU)
(0.836 0.010) e?b2 and
(-0.73 0.10) e.b. ( 1 0 4 RU)
The
values refer to constructive interference.
Results will also be presented for 96ru and ^®Ru.
N.R.C.
TUESDAY, JUNE 13, 1978
ROOM 3018
Chairman: E. Brannen
9:00
CEI
2k2 and
(0.494 0.010) eib
(0.640 0.010) e?b2 and
OPTICAL PHYSICS I I - GUIDED-WAVE OPTICS AND HOLOGRAPHY
Fibre Optic Device Research in the Department of Communications
K.O. HILL, B.S. KAWASAKI and D.C. JOHNSON, Communications ReseAAch CentAd,
Ottawa
During the past year the Optical Communications group of the Department of Communications has
demonstrated several novel devices some of which may find large-scale use in future fiber-optic
networks. These include high-performance access couplers, power combiners and full-duplex links
as well as a new mode-locked source of radiation in the visible. A new photosensitive phenomenon
useful for the fabrication of high-quality tunable filters in optical fiber waveguides will also
be described. The filters are capable of attaining a spectral resolution better than 100 MHz at
optical frequencies. Some possible applications of these unique filter structures will be
discussed.
9:30
CE2 M e r i d i o n a l Ray Model o f a B i c o n i c a l l y Tapered
Step Index O p t i c a l F i b r e
A.W. LIGHTSTONE, F. SZARKA, and H.K. EASTWOOD Canada
Wire and Cable - Fibre O p t i c s , 5770 Royal mount, Montreal
Quebec, H4P 1K5
B i c o n i c a l tapers o f t e n occur i n o p t i c a l f i b r e s and
degrade the performance by causing loss o f l i g h t * on the
o t h e r hand, b i c o n i c a l tapers have r e c e n t l y been designed
and used t o couple l i g h t i n and out o f a f i b r e .
We have
c a l c u l a t e d the i n s e r t i o n l o s s o f such s t r u c t u r e s .
Loss
o f l i g h t i n t o a i r i n the down taper o f a high s i l i c a
f i b r e i s n e g l i g i b l e provided the r a t i o o f the f i b r e d i a meter a f t e r and b e f o r e t a p e r i n g i s g r e a t e r than the
numerical a p e r a t u r e .
L i g h t which remains i n the claddi n g a f t e r the taper i s a l s o e f f e c t i v e l y l o s t , and t h i s
amount o f l i g h t i s estimated by c o n s i d e r i n g the e f f e c t
o f Fresnel r e f l e c t i o n i n the up t a p e r , and, by computer
s i m u l a t i o n , the e f f e c t o f the path l e n g t h o f the rays.
T y p i c a l i n s e r t i o n losses o f . 3 db are p r e d i c t e d .
9:45
CE3
Displacement of an Electromagnetic Beam upon
Transmission Through a Dielectric Slab.- L.A.A.READ,
Wilfrid Laurier Univ., and G.E.REESOR, Univ. ot Waterloo - In the past we have been successful i n applying
a theoretical plane-wave analysis to the pr oblems of
total internal reflection (Goos-Hanchen shi ft) and
external reflection from b oth a semi-infini te l
dielectric sla b.
dielectric medium and a th
We
have now extended our anal ysis to the transimission of
an electromagnetic beam, u sing 3 cm microwa ves,
through a dielectric slab (n = 1.63) approx imately 3X
thick. We are investigati ng, both theoreti cally and
experimentally, the magnit ude of a sideways displacement of the beam, in addit ion to that expec ted by
refraction, as a function of angle of incid' nee of
the beam.
1
Wong, M., Reesor, G.E., and Read, L.A.A., Can. J.
Phys., 55, 1061 (1977). )
Work supported by N.R.C.
25
10:00
Thin-Film Beam Splitter in Guided Wave Optics.
D. VINCENT and J.W.Y. LIT*, LROL. Department of Physics
Laval University, Québec, Canada. G1K 7P4.
11:15
CE8
Visualisation Holographique des Ondes Acoustiques de Surfaces. J. LAPIERRE et M. SILLS, Ecole
Polytechnique de Montréal.
Earlier resu Its on a guided wave beam splitter
have been presented ( 1 » 2 ). Variations of the reflection
coefficient with an,gle of incidence and the shape of the
groove will be repo rted. They will be compared with
2
theoretical calcula tions^ ^ using constant, linear and
parabolic thickness profiles of the groove: the last
one gives the best fit. Angular range of 10 mrad to
switch from 10% to 90% reflection and low insertion loss
are typical. It is easy to obtain 3-dB coupling which
could be applied to interferometers.
On décrit une méthode holographique qui permet de visualiser la distribution d'amplitude et de phase d'une
onde de surface progressive. La théorie montre que
de cette manière on s'affranchit complètement du bruit
causé par la présence de poussières ou d'imperfections
sur les composantes du système optique. Les résultats
expérimentaux indiquent une amélioration du rapport
signal sur bruit d'au moins deux ordres de grandeur
par rapport à la méthode de visualisation directe sans
holographie.
(1)
(2)
D. VINCENT, J.W.Y. LIT, Device Research Conference,
Salt Lake City, Utah (1976) paper II A-5.
D. VINCENT, J.W.Y. LIT, J. Opt. Soc. Amer, 67, 533
(1977).
* Wilfrid Laurier University
10:30
CE5
An Analysis of Optical Waveguide Tapers. T.K.
LIM^*, B.K. CARS IDE and J.P. MARTON ' , PepartmenTof
Engineering Physics, McMaster Univ.—The properties of
waveguide tapers with finite-thickness cladding are
investigated. The taper is approximated as a series of
uniform five-layer waveguides. Mode coupling and
transmission characteristics for typical tapers are
studied by computer simulation, employing an iterative
technique. Strong coupling and efficient conversion
between core and cladding modes are demonstrated for
tapers with various slopes. These results form a
basis for the understanding and interpretation of the
novel featues of fiber taper couplers. For practical
reasons, comparisons are made for results obtained by
using different iteration step-sizes and coupling
schemes. It is shown that for mild tapers, the nearestneighbor coupling approximation is quite adequate; for
steeper tapers, additional neighboring modes should be
taken into account. In addition, it is found that a
relatively large step-size can be employed in the
numerical calculations to reduce the computational cost.
+
Dale Electronics Limited, London, Ontario, Canada.
10:45
CE6
Applications of Tapered Couplers in Integrated
Optics.
G.A. TEH, V. SO, G.I. STEGEMAN, Univ. of
Toronto—A key component in any guided wave system is
the directional coupler. It enables energy to be
coupled, selectively, from one waveguide to another. At
optical wavelengths, the fabrication of synchronous-mode
directional couplers is hindered by severe tolerance
restrictions. Dimensional tolerances of less than 0.1%
are typical. The situation can be improved considerably
by tapering one, or both, of the propagation coefficients. Other applications of tapered couplers include:
frequency filtering, mode discrimination and broadband
coupling.
11:00
CE7
ETUDE DU RETROCOUPLAGE PAR LE MODELE DE L'INDICE EFFECTIF. P. VERLY,
J. LIT*et R. TREMBLAY, Univ.
Laval - - Le modèle de l'indice effectif est utilisé
pour déterminer les trajectoires de faisceaux lumineux dans les couches minces à paramètres lentement
variables, lorsque la conversion de modes est très
faible (Ulrich 1971). Nous montrons qu'on peut
également utiliser cette méthode pour calculer le
rétro couplage entre deux modes provoqué par une
variation périodique des paramètres de la couche.
Nous comparons nos résultats avec ceux déjà publiés
sur le sujet. Nous montrerons une application aux
guides tri-dimensionnels en couche mince.
R. Ulrich & R.J. Martin (sept. 1971)
Appl.-Opt. H) pp. 2077-2085
*Wilfrid Laurier University
11:30
Holographie Image Degradation Due to DepolarCE9
ization of Illumination.* H. GHANDEHARIAN and W-M.BOERNER, Univ. of Manitoba.-The effects on image quality
due to polarization changes of the illuminating beam
after scattering by an object are studied. These effects include a decrease in signal-to-noise ratio (decrease in fringe visibility) of the hologram and, for
an extended object, a loss of information of those segments of the object that have large curvature (edges,
discontinuities, etc.). The autocorrelation function
of the transmittance of a nonlinearly recorded hologram
of a diffuse object is obtained.1 It is shown that the
change of polarization of the illuminating beam by the
object not only reduces the images due to the nonlinearity of the recording medium. This new distorting
effect, which appears as a multiplicative factor, is
dependent on the irradiance distribution of the object's cross-polarized component. A simple way of decreasing the above mentioned degradation effects is
suggested.
^H.Gharideharian, W-M.Boerner, J. Opt. Soc. Am. 68, June
1978, in print.
*Supported by the National Research Council Grant#A7240
11:45
CE10
Holographic Transmission Gratings for the
Soft X-Ray Region.
E. KALLNE and H. W. SCHNOPPER+,
Univ. of British Columbia.— In the soft x-ray region,
5-40A, the low reflectivity at grazing angles as well
as the strong dependence on surface contamination has
hindered production of efficient grating instruments.
The interferometrically formed, electrodeposited
transmission gratings are produced as free-standing
gold structures with 500-1000 1/mm. We have measured
efficiencies of these gratings using the continuous
synchrotron radiation from Stanford Synchrotron Radiation Laboratory. The complete destruction of even orders and the high efficiencies for these gratings make
them promising as dispersive elements in monochromators. Furthermore, the development within x-ray lithography opens possibilities to produce these gratings
with blazing structure.
^Center for Astrophysics, HCO/SAO, Cambridge,
Massachusetts.
26
TUESDAY, JUNE 1 3 ,
ROOM 3 0 2 4
Chairman:
T.W.J.
1978
INTERACTIONS LASER-PLASMA
Johnston
9:00
CF1
Le comportement au seuil de l'instabilité de
désintégration â trois ondes dans un plasma fini inhomogène. V. FUCHS, G. BEAUDRY et M.M. SHOUCRI, direction Sciences de base, Institut de recherche de 1'HydroQuébec, Varennes, Québec, Canada JÛL 2P0 — Nous examinons, numériquement et analytiquement, l'instabilité absolue à trois ondes dans un plasma fini inhomogène, en
fonction de la longueur L de plasma, de la longueur
d'amplification nonlinéaire LQ et du gradient K de mésadaptation des vecteurs d'onde. Dans le cas d'un couplage uniforme, la borne de stabilité dans le plan (A,
a) devient a = 8/v quand a » 1, le plasma tend à faire
la conversion d'ondes dans une zone de largeur 4/kLQ,
et la région de résonance se trouve à une distance
2/icL0 de la frontière irradiée par laser. Dans le cas
de coefficients de couplage non-uniformes, la résonance
est déplacée près du point de couplage maximum comme résultat d'un accroissement nonlinéaire du gradient effectif lorsqu'on s'éloigne de ce point, et de l'interférence provenant des régions près des frontières.
L'importante interférence émergeant des régions de très
faible couplage est due à la réponse de la phase totale
qui ne dépend que très peu de la forme spatiale du couplage.
9:15
CF2
Observation of nonthermal ion fluctuations in
a fast z-pinch discharge.
J. MEYER, G. ALBRECHT and
B. HILKO, Univ. of British Columbia — A fast z-pinch
discharge in helium is investigated by various diagnostic techniques. During the dense pinch phase the
density is observed to exceed 10
while the electron temperature reaches values approaching 40 eV.
During this phase of the discharge nonthermal ion fluctuations are detected by Thomson scattering of ruby
laser light. A detailed analysis of the spectrum of
these microturbulences is presented.
9:30
CF3
Heating of a z-pinch plasma by C02~laser
light. J. MEYER, G. ALBRECHT and B. HILKO, Univ. of
British Columbia — A z-pinch plasma is irradiated by
focussed light from a 250 MW C02 laser. The resulting
change in plasma parameters as well as the stimulation
of large amplitude ion acoustic waves is investigated
by means of Thomson scattering of Ruby laser light.
9:45
CF4
L'interaction d'un faisceau laser CO? avec le
plasma dense produit par un Z-pinch. C.R. NEUFELD,
P. NOEL et A. ROBERT, direction Sciences de base, Institut de recherche de 1'Hydro-Québec, Varennes, Québec,
Canada J0L 2P0 — Nous présentons les résultats d'une
étude expérimentale de l'interaction d'un faisceau laser CO2 avec un plasma dense d'hydrogène. La cible
plasma est produite par une décharge rapide à striction
axiale. Une analyse spectrale du rayonnement émis par
ce plasma indique une densité électronique maximum de
1 x 10l9 cm~3 approximativement. Nous évaluons la température cinétique du plasma à environ 10 eV. Nous
avons irradié cette cible plasma avec une impulsion laser CO2 (40 J, 50 ns) incidente dans la direction radiale. Environ 2% du rayonnement incident est rétrodiffusé dans l'angle solide de la lentille de focalisation du faisceau laser. Le spectre du rayonnement rétrodiffusé est déplacé vers les plus grandes longueurs
d'onde, par rapport au spectre du rayonnement incident.
En postulant la diffusion Brillouin stimulée comme mécanisme physique responsable du rayonnement rétrodiffusé, nous évaluons la température du plasma pendant
l'interaction laser à plus que 100 eV.
10:00
CF5
S.B.S. from an Underdense Laminar Gas Jet — A
Brillouin Switch?, N.H. BURNETT, H.A. BALDIS, P.B.
CORKUM and J.C. SAMSON, N.R.C. , — A laminar molecular
gas jet has been developed as a target to study radiative instabilities in homogeneous underdense plasmas.
A stable two-dimensional laminar flow is obtained by
discharging high pressure nitrogen through a convergentdivergent (supersonic) nozzle into ambient He at a pressure of ^2 Torr. The
rnm thick, 1 cm wide jet is
illuminated transversely with a train of 2 ns 10.6 ^m
pulses from a high power mode-locked C02 oscillator.
With a molecular nitrogen density of 1.5x 1017cm~3
(available electron density ^0.2 n c ) it is observed
that the breakdown threshold in the jet is
x 1012W/cma
for 2 ns pulses and that with suitable preionization,
single pulse reflectivities through the Brillouin instability can approach 100%. Plasma diagnostic studies
and 2D numerical simulation of the resulting plasma
will be described. The spectral properties and optical
quality of the reflected radiation will be discussed in
connection with possible applications of this device as
a switching and isolation element for high power infrared lasers.
10:30
CF6
X-Ray Emission and Two-Plasmon Decay Instability in C0 2 Laser-Plasma Interaction. A.K.H. NG, L.
PITT, D. SALZMANN and A.A. OFFENBERGER, Dept. of Elect.
Eng., Univ. of Alberta - Laser induced parametric
instabilities in underdense plasmas have been studied
by irradiating a free-jet, hydrogen gas target with a
long-pulse (40 nsec pulse-width), multimode CO2 laser
at focussed intensities up to 1 0 ^ watts/cm^. The
spectrum of X-ray emission from the plasma was measured, which revealed a thermal continuum as well as
a non-thermal, high energy tail. An electron temperature Te of 120 eV was obtained from the thermal portion
of the X-ray spectrum. This is consistent with T e
determined from the spectrum of stimulated Brillouin
backscatter. Correlation of the high energy X-ray
emission with instabilities will be discussed. The
two-plasmon decay instability has also been studied
by measuring the spectrum of 1. harmonic emission. Such
a spectrum showed a clear red^shift of %2u)g, where u)g
is the ion acoustic frequency determined from
stimulated Brillouin scattering measurements. Measured
value of the threshold intensity for the two-plasmon
decay is in good agreement with theoretical predictions
for an inhomogeneous plasma.
10:45
CF7
CCX, Laser Induced Parametric Instabilities in
an Underdense Plasma* A.A. OFFENBERGER, A.K.H. NG, L.
PITT and D. SALZMANN, Dept. of Elect. Eng., Univ. of
Alberta - Laser induced parametric instabilities in an
underdense plasma have been studied using a hydrogen
gas target and a UV preionized CO2 laser. By operating
the laser in an unstable resonator configuration,
narrower bandwidths as well as higher focused intensities (£ 1 0 ^ watts/cm^) can be achieved. Consequently,
reflectivities in excess of 30% have been observed in
the stimulated Brillouin backscatter. Temporal characteristics of the Brillouin signals further showed
modulations as high as 100%, providing direct evidence
of wave breaking at high pump intensities. Saturation
of the instability was observed and spectra of the
Brillouin backscatter have been measured at different
laser intensities. Measurements on the two-plasmon
decay instability will be discussed. Other diagnostics
include X-ray measurements, streak photography and
laser interferometry.
27
AMORPHOUS MATERIALS AND RANDOM ALLOYS
TUESDAY, JUNE 1 3 , 1 9 7 8
ROOM 3026
Chairman:
J . L . Brebner
9:00
CGI
Amorphous Silicon and Amorphous Silicon-Hydrogen Alloys
w. PAUL, HaAvaJid
Univ&ulty
Recent experiments on amorphous silicon-hydrogen alloys prepared by r.f. sputtering in argon will be
reviewed. The results will be considered in relation to earlier experiments on amorphous silicon
sputtered without hydrogen and current work on a-Si-H alloys prepared by glow discharge decomposition
of S1H1+. The extent to which the properties of the ideally-coordinated, chemically-pure amorphous
silicon may be inferred will be discussed. Also, optimization of various device properties such as
quantum efficiency of photoluminescence, photoconductive response, and solar cell efficiency will be
examined.
9:45
CG2
Conduction Due to Ba.'.d Edge Electrons in
Amorphous Ge. M.M. PANT and B.Y. TONG, Dept. of Physics
and Centre for Interdisciplinary Studies in Chemical
Physics, U.W.O., London.—Various experimental work has
led to the conclusion that conductivity in amorphous
materials is dominated by carriers in band tails. A
theoretical calculation requires a knowledge of the
density of states near the band edges. We have used the
results of Extended Huckel theory calculations for
sev-ral models of amorphous Ge to fit analytic expressions of the square root and exponential type near the
ban.' edges. Error analysis indicates that with increasing strain in the models attempts at square root
fit fail. We use the two forms of the density of states
to calculate the conductivity due to both localised as
well as extended states as a function of temperature
and compare them with experimental results.
10:45
Amorphous versus Random Approximation for
Calculations in Solids.* B. M. LATTA, Queen's U n i v . —
At reduced energies below e = 0.1, Monte Carlo results
for the lateral straggle of projectiles, under a mask
during implantation, are found to be 50 to 200 percent
greater than previous numerical estimates. The Monte
Carlo results are thus in excellent agreement with
existing experimental data 1 . Next the transport
equations are derived in the approximation of equal
spacing between collision centres. Based upon these
modified transport equations, it is suggested that the
difficulty in the previous numerical estimates arise
from the approximation of the solid as a random rather
than amorphous target.
A. Grant, J. S. Williams, and D. Dodds, Ion beam
surface layer analysis Volume 1 (Plenum, New York,
N.Y.) 235, 1976.
*Supported by the National Research Council of Canada.
10:00
CG3
Wave Function Localization in Two- and ThreeDimensional Random Binary Alloys. M.M. PANT, B. HEDE
and B.Y. TONG, Univ. of Western Ontario, London.— It
has been shown by us that local Green's function
approach is a practical method to study the nature of
the wavefunctions (whether extended or localized) in a
large disordered system.1
In this work we investigate
the possibility that extended states can exist in both
the majority (host) and the minority (impurity) bands
in 3-D cubic lattice, in contrast to 2-D square-lattice
where it is unlikely to have large extended state
regions in both bands.
'B. Hede and B.Y. Tong, Solid State Comm. 25 269 (1978).
10:15
CG/
*
Trapping Centres in Doped Glasses. M. SAYER,
R. QUIST and E.J. PRASAD, Queen's Univ., Kingston, Ont.
Some transition metal ions act as trapping centres when
introduced into the host lattice of a semiconducting
phosphate glass. The conductivity of the glass is
modified by several orders of magnitude with the introduction of small quantities of impurities.
Experiments
have been carried out to study the AC and DC behaviour
of WÛ3-V2O5-P2O5 glass over a wide range of temperature
and frequency and under low and high values of applied
field. The results may be explained in terms of a
hopping process between two distinctive sites - the
impurity site acting as a trap. Hopping distances
calculated from a model using dielectric data show good
agreement with hopping distances derived from high field
measurements.
11:00
CG6
R e s i s t i v i t y of A m o r p h o u s A l l o y s at
Very Low Temperatures. R . W . C O C H R A N E , F . T . H E D G C O C K , B . J . K A S T N E R , W . B . M U I R and M . J . Z U C K E R M A N N ,
M c G i l 1 U n i v . , — W e h a v e m e a s u r e d the r e s i s t i v ity of a s e r i e s of a m o r p h o u s m e t a l m e t a l l o i d
a l l o y s d o w n to 6 0 m K . We o b s e r v e t h r e e d i s t i n c t
c l a s s e s of b e h a v i o u r in the low t e m p e r a t u r e reg i o n : 1 ) s u p e r c o n d u c t i v i t y ; 2 ) s a t u r a t i o n of the
r e s i s t i v i t y b e l o w IK and 3 ) i n c r e a s i n g r e s i s t i v i t y b e l o w IK.
A l t h o u g h the r e s i s t i v i t y
c h a n g e for a l l o y s in c a t e g o r y 3 is s m a l l , t h e r e
is no s a t u r a t i o n in the r e s i s t i v i t y d o w n to
the l o w e s t t e m p e r a t u r e m e a s u r e d . In the 1 to
1 0 K r e g i o n a l l the a l l o y s h a v e a n e g a t i v e
t e m p e r a t u r e c o e f f i c i e n t of r e s i s t i v i t y . M o s t
of the s a m p l e s h a v e a r e s i s t a n c e m i n i m u m followed by a p o s i t i v e t e m p e r a t u r e c o e f f i c i e n t of
r e s i s t i v i t y at h i g h e r temperatures 1 ". C a t e g o r ies 1 and 2 a r e c o n s i s t e n t w i t h p r e s e n t theo r i e s of the r e s i s t i v i t y of d i s o r d e r e d m a t e r i a l s ; h o w e v e r , category
3 requires a modificat i o n of the t h e o r i e s .
^R . W . C o c h r a n e
1799(1977).
and
J . 0 . S t r o m - O l s e n , J . P h y s . F T.*
28
TUESDAY, JUNE 1 3 , 1 9 7 8
ROOM 3 0 2 8
Chairman:
p.A. E g e l s t a f f
9:00
CHI
Temperature Dependence of Phonons in Liquid **HeA.D.B. WOODS, E.C. SVENSSON and R. SCHERM*, A.F.C.L.,
Chalk River.—Scattered-neutron enerqy distributions
obtained as part of an earlier study1 of liquid "He did
not show well-defined peaks at T = 2.1 K for wave vectors near the first maximum of the dispersion curve. It
was not clear at that time whether this result was due
to poor statistical accuracy or to very short phonon
lifetimes. In order to establish the behavior more precisely, a new neutron-scattering study has been carried
out at the NRU reactor, Chalk River, for wave vectors
of 0.80, 1.13, 1.30 and 1.40 S" 1 and for temperatures
of 1.00, 1.38, 1.77, 1.97, 2.07, 2.12, 2.15, 2.26 and
4.21 K (TX-2.17 K). At the lowest temperatures each
distribution consists of the familiar1 sharp
"one-phonon" peak and a broad "multiphonon" component
at higher energies. As the temperature is raised, the
one-phonon peak broadens but it is still distinguishable from the multiphonon component even at T = 2.15 K.
Above
, however, there is no distinguishable
one-phonon peak.
•R.A. Cowley and A.D.B. Woods, Can. J. Phys. 49, 177
(1971).
•visitor from Institut Laue-Lanqevin, Grenoble, France.
9:15
CH2
An Accurate Intermolecular Potential for Helium.*
R. A. AZIZ, V. NAIN, J. S. CARLEY, Univ. of Waterloo
W. L. TAYLOR and G. T. McCONVILLE, Mound Laboratory,
Monsanto Research Corporation, Miamisburg, Ohio—
A new empirical helium potential of the HFD form suggested by Ahlrichsl et al. is presented. It has as
input data recent ab initio calculations at short
(4-5 a.u.) and long range. The remaining one free
parameter was adjusted to give a good fit to the precise
thermal conductivity data of Haarman2. Overall the
potential predicts transport properties and virial
coefficients over a wide range of temperatures better
than other recently proposed potentials. In particular
the virials are accurately predicted from 1.5 to 1600 K.
HELIUM, SIMPLE GASES, LIQUIDS AND SOLIDS
9:45
CH4
Two and Three Body Potentials and the Structure
of Dense Krypton Gas. A. TEITSMA and P.A. EGELSTAFF,
Univ. of Guelph, Guelph, Ont.--We have made careful
measurements of the structure factor of dense krypton
gas at 9 densities from 6.2 to 2.9xin 2 7 atoms/m' and at
T = 295°K and compared these measurements to Monte Carlo
and virial expansion calculations based on the Barker
et al. pair potential and the Axilrod-Teller triple
dipole potential. The differences between the calculated and measured results are interpreted as partly due
to errors in the pair potential and partly clue to short
range terms in the three body potential.
10:00
CH5 The Mutual Diffusion Coefficient of Krypton-Noble
Gas Mixtures. D. CAIN and W.L. TAYLOR, Mound Laboratory,
Monsanto Research Corporation, Miamisburg, Ohio.— The
mutual diffusion coefficents of krypton-noble gas
mixtures have been measured as a function of temperature
from approximately 300 to 1200 K. A dual chamber
apparatus with no moving parts was used with an
experimental procedure that is independent of Initial
conditions. The present results extend the temperature
range of previously reported studies using a similar
method bv over 400 K. Transport collision integrals
have been computed for several inter-molecular potential
functions and used to calculate theoretical diffusion
coefficients which are compared to the experimental
results.
10:15
CH6
Structure of Hydrogen Chloride Gas. A. K. S0PER
and P. A. EGELSTAFF, Univ. of Guelph.—The intermolecular partial structure factors (e.g. H-H structure
factor, etc.) for hydrogen chloride are measured. The
experimental method, using isotopic substitution of both
hydrogen and chlorine nuclei, and neutron diffraction,
is described. Preliminary results are presented for
this gas at 80 C and pressures below critical pressure,
in which region of the PVT diagram it is expected that
the 'non-ideal' aspects of the structure factors are
dominated by the second virial coefficient. These are
compared with a Monte Carlo simulation in the same
region.
Ahlrichs, P. Penco and G. Scoles, Chem Phys 19, 119
(1976).
2
J. W. Haarman, AIP Conf. Proc. II, 193 (1973).
*
Supported by the National Research Council of Canada
and the U.S. Department of Energy.
9:30
CH3
Effect of Boundary Conditions on Superfluid
Helium In Restricted Geometries below 0.5K.* H. R.
PAJKOWSKI and R. K. PATHRIA, Univ. of Waterloo —
The recent theoretical work of Haug1 on finite size
effects in superfluid helium confined to restricted
geometries (such as thin films, narrow channels, etc.)
is extended to a variety of boundary conditions that
can be imposed on the system. Comparison of theoretical results with experimental data suggests that
Neumann boundary conditions might be the most
appropriate ones for the system in question.
1
H. Haug, J. Low Temp. Phys. 12, 479 (1973).
* Supported, in part, by the National Research
Council of Canada.
10:45
CH7
E l e c t r o n i c S t r u c t u r e o f the Self-Trpped Exciton
i n Rare Gas S o l i d s . L . J . Lewis and K.S. Song, Univ. o f
Ottawa
We r e p o r t here the r e s u l t s o f our i n v e s t i g a t i o n on the e l e c t r o n i c s t r u c t u r e o f the s e l f - t r a p p e d exc i t o n i n r a r e gas s o l i d s : A r , Kr and Xe. The wave f u n c t i o n s and the energy l e v e l s o f the e x c i t e d s t a t e s o f
the STE are obtained using the e f f e c t i v e mass d i e l e c t r i c
continuum model, i n c l u d i n g d i f f e r e n t c o r e c t i o n terms.
We thus obtained a Rydberg s e r i e s corresponding t o a ,
a and TT s t a t e s . These are compared to the experimeHtal
works oT luminescence and a b s o r p t i o n i n v o l v i n g the STE.
The two lowest o s t a t e s from which the e l e c t r o n
can recombine r a d i a t i v e l y are found t o be i n good agreement w i t h the luminescence d a t a : the energy d i f f e r e n c e
o f the two i n i t i a l s t a t e s being 1.5eV ( Ar nad Kr ) and
1.2eV( Xe ) , compared t o the experimental energy d i f f é r é
nee o f the two lum. bands ( 1.4eV f o r Ar and 0.6eV f o r
Xe ) . O p t i c a l a b s o r p t i o n energies from the lowesto
state to a and* ( 1.2eV f o r Ar and Kr and.1.0 eV fSr Xe)
1
compare s e l l wTth the r e s u l t s o f Kanzaki ' . These w i l l
be compared w i t h the STE i n a l k a l i h a l i d e s .
(1) A. Gedanken.B.Raz and J . J o r t n e r , J . Chem.Phys.59,5471
—
(1973)
(2) T.Suemoto.Y.Kondo and H.Kanzaki, Sol .St.Coirm. ,(1978)
29
11:00
CH8
Pockels Coefficients
of the Rare-gas Solids.
J. E. SIPE, Univ. of Toronto—We have derived expressions for the Pockels elasto-optic coefficients from a
microscopic model appropriate for the rare-gas cyrstals1.
The constituent atoms are regarded as polarizable particles coupled by the dipole-dipole interaction, which
we treat by introducing the usual microscopic effective
electric field, and by the short-range higher multipjle
and Van der Waals interactions, which are included by
associating with each atom an effective polarizability
which depends on the distance between the atom and its
nearest neighbors. Comparison with experiment indicates
that the effect of these short-range interactions on
the polarizability of atoms in rare-gas crystals is
smaller than commonly assumed.
11:15
CH10
Spin Conversion in Pure 13 CH U * B.M. WOOD, J.
HIGINBOTHAM, and R.F. CODE, Univ. of Toronto—We report
the first consistent NMR determination of the long
and short term proton spin symmetry conversion times in
Phase II of pure ^CH^. The ordered sublattice time
constants are 154!t^jJ hours at 1.85°K and 4 1 1 ^ hours at
4.2°K, and the corresponding values of the disordered
sublattice time constants are 0.51—81 tj§ hours and
0.91—8ill hours, respectively. The consistency of these
results are examined with respect to the mechanism proposed by Nijman and Berlinsky1 which has clarified the
roles of sublattice structure, lattice vibrations and
molecular hyperfine interaction during the conversion
process.
1.
1
To be published, Can. J. Phys.
A.J. Nijman and A.J. Berlinsky, Phys. Rev. Lett. 38.»
408 (1977).
A
Work supported by the National Research Council of
Canada.
11:15
CH9
Collisional Polarizability and Elastic Properties of Methane." S.C. RAID arri B.P. STOICHEFF, Dept.
Fhysics, Univ. of Toronto.-The elastic constants and elasto-optic coefficients of methane have been determined
by high-resolution Brillouin spectroscopy of sinqle crystals at 90.51'. Available theoretical results for the
lattice dynamics and polarizability of the solid have
been compared with the experimental results at the triple point and used to derive the adiahatic bulk modulus,
Poisson ratio, Debve temperature, thermal Gruneisen parameter and the collisional polarizability tensor. Flastic anisotropy was observed to be exceptionally large in
methane, and a remarhable "slowness" characterized TA,
<110> phonons, giving evidence for strong rotation-translation coupling between molecules at a temperature well
above that of the phase transition (at 20.4K).
11:45
CH11
Low-Density Non-Bloch Modes in Transverse WMR
in Molecular Gases.* F.R. McCOURT and G. TENTI, Univ.
of Waterloo — The low density behaviour of the spectral lineshape function associated with the relaxation
of the transverse component of the nuclear magnetization of a homonuclear diatomic gas of spin-4! nuclei is
studied from the standpoint of a recent kinetic theory
approach1'2. It is shown that, as a critical density
is approached from above, the lineshape loses its structure, thus indicating a breakdown of the phenomenological (Bloch) theory, and hence a passage to non-exponential decay in the time domain. As the density is
further decreased, the spectrum shows structure again
in the form of two sharp peaks which are non-Lorentzian in shape. The physical meaning of these lowdensity non-Bloch modes will be illustrated by means
of an intuitive picture.
1
G. Tenti and F.R. McCourt, J. Chem. Phys. 65, 623
(1976).
F.R. McCourt and G. Tenti, Chem. Phys. (in press).
Supported by N.R.C.
*Supported by the National Research Council of Canada
30
TUESDAY, JUNE 13, 1978
ROOM 2024
Chairman: A.V. Gold
13:30
DAI
CONDENSED MATTER SYMPOSIUM
One-Dimensional Metallic Incommensurate Chains in Hg2.86
W.R. DATARS, McMaiteA
UntveAilty
6.
Mercury fonas one-dJUnensional metallic chains having a Hg-Hg distance that is incommensurate
with the host lattice. There is no interchain ordering at room temperature but phase ordering
between chains occurs below 200 K. The metallic chains give the compound many unusual
properties. The electrical conductivity, optical reflectance and thermoelectric power are
highly anisotropic. The coefficient of thermal expansion changes at 200 K. Mercury is excluded
from the compound below 200 K. Unusual superconductivity results from the excluded mercury.
A description of this linear-chain compound and an explanation of its unique properties will
be presented.
14:15
DA2
Spin-Dependent Oscillations in Metals - a Review of Theory and Experiment*
M.B. WALKER, UnivVi&ity
of, Toronto
Microwave transmission experiments reporting the observation of spin waves, frequency dependent
conduction electron spin resonance, and Larmor waves are reviewed, as are current theoretical
ideas relating to the interpretation of such experiments. Some unpublished results concerning
Larmor waves will be presented.
«Supported by the National Research Council.
15:00
15:15
DA3
Break
Computer Simulation of Collective Modes in Solids
M.L. KLEIN, National
RWETWCFI Council O{ Canada
The molecular dynamics technique is now widely used to calculate the time dependent properties of
many body systems. This paper reviews the application of this computer simulation technique to
the calculation of the normal modes of vibration of solids and their lifetimes. Examples will be
representative of most classes of solid found in nature, namely the inert gases, ionic crystals,
metals, alloys, and molecular solids.
TUESDAY, JUNE 13, 1978
ROOM 2028
Chairman: C. Richard
13:30
DB1
Tokamaks and Toroidal Fusion Systems
D. JASSBY, P/Unceton PlaAma Phyiia
Labonatoly,
SYMPOSIUM ON FUSION - STATE OF THE ART AND PROSPECTS
Viu.nc.eton
The performance of present-day tokamak plasmas is reviewed and related to fusion-reactor requirements. In
very dense tokamak plasmas at Tt - T e * 1 keV, ntE-values up to 2 x 10 13 cm~3s have been attained. With
neutral-beam injection into moderate-density plasmas, the bulk-ion temperature has been increased to 2.2 keV,
with an equivalent Ti of 5 keV including nonMaxwellian ions; accompanying parameters are T e - 2 keV and
nig * 3 x 10 1 2 cm~3s. With deuterium neutral-beam (36 keV) injection into deuterium plasmas, up to 10 12
fusion neutrons per pulse have been obtained. These results are encouraging for the near-term demonstration
of a tokamak fusion-neutron source with Q p (fusion power/injection power) - 1. In present experiments the
rate of cross-field Ion energy transport is "classical", while the electron energy transport rate, though
anomalously large, scales favorably for reactor requirements. The prospects for high-Qp or ignited operation
depend most importantly on effective impurity control. Economic feasibility of a toroidal electrical power
reactor depends also on achieving sufficient plasma pressure to give average fusion power densities of at
least 3 MW/m3 with Qp £ 10, as well as quasi-steady plasma fueling, temperature control, and ash removal.
31
14:15
DB2
15:00
DB3
Inertial Confinement Fusion
K.A. BRUECKNER, UvUveAAiXy o^ Calliofiwux,
Mirror Fusion
T.K. FOWLER, Lammce
Radiation
San V-Lego
Laboictfoiy, CaLLfioirUa
The mirror approach is now the principal alternate to the tokamak in the U.S. magnetic fusion energy program.
The program has been greatly expanded over the last two years in response to favorable results from the
2XIIB mirror experiment at the Lawrence Livermore Laboratory. High values of the mean ion energy W^ have
been achieved, in the range 9 to 13 keV. Because the density is high and the magnetic field is relatively
weak (a maximum of 7 kilogauss within the plasma) , the peak values of beta (B - 8TT n W-J^/B2) are correspondingly
quite high, of order 1.2 to 1.6. The product of density and lifetime (nip for particles, riTg for energy)
is an order of magnitude higher than that achieved in previous mirror experiments. The results from the
2XIIB experiment, supported by a corroborating theory having a favorable extrapolation, have given renewed
encouragement that nearly classical plasma confinement can be obtained in large sized mirror devices. The
major disadvantage is the relatively poor particle confinement, even if stability is achieved, leading to a
power amplification factor Q of order unity. (0 is defined as the ratio of fusion power output to the
neutral-beam power continuously injected to sustain the reaction.) Two means of enhancing the Q of mirror
machines have been selected for special attention, forming the basis for the major mirror experiments to be
carried out at Livermore over the next several years. These are the Tandem Mirror and the Field Reversed
Mirror concepts. Theoretically, each of these concepts might be able to attain Q = 5 or more. Success with
either or both of these approaches would point the way toward fusion power plants with many attractive features.
15:45
DB4
16:30
DB5
Alternate Fusion Concepts
R.C. DAVIDSON, Office of Fusion
Energy,
Department
of Energy,
Panel Discussion
TUESDAY, JUNE 13, 1978
ROOM 2032
Chairman: J . E . K i t c h i n g
13:30
DC1
14:15
DC 2
15:00
15:15
DC3
Washington
APPLIED NUCLEAR PHYSICS AND NUCLEAR INSTRUMENTATION
Radio-Carbon Dating Using a Tandem Accelerator
E. NELSON, Department of Archaeology,
Simon F raser
Kaon Factories
M.K. CRADDOCK, University
of British
University
Columbia
Break
Pre-Clinical Studies on the Biomedical n-Beam at TRIUMF
L.D. SKARSGARD, R.M. HENKELMAN, G.K.Y. LAM and B. PALCIC, British
Columbia
Cancer
A special meson beamline has been constructed at TRIUMF to test the effectiveness
of beams of negative n mesons for the radiation treatment of cancer. The beamline
can be tuned to deliver
of any momentum from 20 to 210 MeV/c, corresponding
to ranges in tissue of 0.01 to 32 cm. The advantage of TT- beams stems from the
process of star formation which occurs when the TT~ comes to rest and is captured
by an atomic nucleus which subsequently disintegrates. The resulting release
of energy gives improved dose localization in the tumour and the densely ionizing
fragments are also more effective in destroying tumour tissue. Results will be
presented of physical and biological experiments which are being carried out on
the beam prior to the beginning of patient treatment. Treatment will get underway
soon after regular operation at 100 ua is available.
Foundation
32
TUESDAY, JUNE 1 3 , 1 9 7 8
ROOM 3 0 0 6
Chairman:
B. M a r g o l i s
14:00
DDI
15:00
15:15
DD2
ELEMENTARY PARTICLES - THEORY
Current Status of New Quarks and Leptons
G.L. KANE, Univesu-cty o& Michigan
Break
Quark Models and Quark Masses
P. O'DONNELL, UnlvemiXy
oi
Toionto
16:15
DD3
First Order Fluctuations about a Smeared Meron
Pair• D.G. LAUGHTON,* Princeton University—A brief
introduction is given of the Princeton programme to
examine the long distance behaviour of Quantum Chromodynamics.1 Details are presented of the calculation
of the contribution to the vacuum-to-vacuum amplitude
of the region in field space about the field known as
a smeared meron pair.2 The importance of this for a
possible mechanism for colour confinement is partially
elucidated.
l
C.G. Callan, R. Dashen, D.J. Gross, Phys. Rev. D
(to appear)
?
D.G. Laughton (to be published)
NRC Postgraduate Scholarship Holder
TUESDAY, JUNE 13, 1978
ROOM 3022
Chairman: J . Van Dyke
13:30
DEI
A Local Field Study of Molecular Dynamics in
Muscle Tissue between 293 and 238K. H. PEEMOELLER, L.J.
SCHREINER and M.M. PINTAR, Dept. of Physics, Univ. of
Waterloo—The local field of proton spins in the rotating frame1 has been measured in normal and isotonic
100% deuterated mouse muscle from 20 to -35°C. At 20°C,
in normal mouse muscle, 9±2% of the protons see a local
field of 0.7+0.2G. In the deuterated muscle, where
only protons on macromolecules contribute to the proton
signal, 50±5% of the protons see a local field of 0.8±
0.2G and the remainder see a local field less than 0.2G.
In the frozen phase a comparison between normal and
deuterated muscle data has shown no local field due to
nonfreezable water.Q Therefore the nonfreezable water
molecules above -35 C diffuse rapidly (on the time scale
of the dipolar period). The concepts of bonded and
nonfreezable water in tissue will be analyzed.
*See Appendix in R.G.C. McElroy, R.T. Thompson and
M.M. Pintar, Phys. Rev. A 10, 403 (1974).
BIOPHYSICS
13:45
DE2
Selenium Isotope Selectivity During MicroBiological Selenite Reduction* K. RASHID\ H. R.
1
KROUSE , E. LAISHLEY2, The University of Calgary and
R. G. L McCREADY, Department of Energy, Mines and
Resources .—Variations in the natural
abundance ratio were previously reported and attributed
by indirect observations to biological isotopically
selective processes . During chemical reduction,
76
SeO3 was found to be converted to elemental selenium
about 1.015 times faster than 82Se0f 3'1'. This kinetic
isotope effect was identified with the initial Se-0
bond cleavage. In the present work, an enteric organism Satmone.Ua ap. and the well-known non-symbiotic
nitrogen fixer CloitAidiurn
pabteuAianum have been found
to exert isotopic selectivity during selenite reduction
76
with Se03 being converted from 1.01 to 1.0U times
faster than 82 Se03. Hence the overall isotope fractionation during microbial selenite reduction depends
upon factors additional to the initial Se-0 bond
rupture.
•Supported by the National Research Council of Canada.
'Department of Physics
department of Biology
3
Krouse, H.R. & Thode, H.G.,Can. J. Chem.ItO,367 (1962)
"Rees, C.E. & Thode, H.G., Can. J. Chem. 5E.U19 (l?66)
33
14:00
DE3
Optical absorption and color Information
distributed in conical fibers. J.A. MEDEIROS,
S.JOHN, J.W. McGOWAN, Univ. of Western Ontario. —
Optical propagation in sufficiently small fibers can
occur in only the lowest-order dielectric waveguide
mode. If such a fiber is tapered, mode cut off results
in an attenuation of the amount of light illuminating
the smaller diameter regions of the fiber core. Since
cut-off conditions depend on the ratio of fiber
diameter to optical wavelength, this attenuation is
differential with the color of the illuminating light
so that the longest wavelengths attenuate most
rapidly. We have calculated the distribution of
optical energy absorbed in conical fibers with physical
parameters comparable to those of the retinal cones.
Various distrubtions, densities, and wavelengths of
maximum absorption of rhodopsin-like photopigments
filling the cones are examined. Simple differentiation of the optical absorption in such physical
models gives the same kind of color information
produced by the human retina, i.e., an opponentcolor code. Work supported by Surgeon General's
Office, U.S. Army.
11:15
DE6
Stable Sulphur Isotope Labelling as a Tool for
Elucidating Atmosphere-Biosphere Interactions and Biological Mechanisms* H. R. KROUSE and H. M. BR0W1J, The
University of Calgary.—Variations in the 3 U S/ 3 2 S
abundance ratio in commercial chemicals and terrestrial
specimens coupled with the precision of stable isotope
mass spectrometry provide the basis for stable sulphur
isotope labelling techniques. With this technique, the
simultaneous metabolism of two sulphur compounds by
bacteria has been successfully studied. In another
study, potted plants with 3I*S/32S abundances differing
from that of the atmosphere have been set out and
monitored isotopically throughout the growing season.
The data provide information on the competition
between uptake from the air and soil as well as how
soil cover affects these relative rates.
*
Supported by the National Research Council of Canada,
The University of Calgary Interdisciplinary Sulphur
Research Group (UIJIS'JL) and Alberta Environment.
14:15
DE^
Use of Optical Diffraction Methods for Laser
Damage Studies in the Retina. J.A. MEDEIROS, B.B0RWEIN,
J.W. McGOWAN, Univ. of Western Ontario. — As the
number of high powered lasers increases, and their
frequency and pulse duration changes, it becomes
necessary to establish safety standards to protect
particularly the eyes of those using this new tool.
To do this one must study the absorption in the retina
of laser light of different intensity, duration and
frequency. In this report we describe the application
of the Fourier transforming properties of an optical
system to produce a diffraction pattern or mosaic of
graded lesions on the retina of the eye. The use of
a variety of diffraction gratings has made it possible
for us to tailor the pattern so that we accurately
know the position and energy density for each order
within the pattern. For these studies we have used
both ronchi rulings and phase objects with sinusoidal
modulation. This work has been supported through the
Surgeon General's Office, U.S.Army.
15:15
DE7
A Meter f o r Measurement of the Burton S t i l l
Shade Temperature. L. MACHATTIE and L. KUEHN, DCIEM-The Burton S t i l l Shade Temperature (SST) i s a c o l d
s t r e s s index i n c o r p o r a t i n g e f f e c t s of a i r temperatures,
wind and r a d i a t i o n on working c l o t h e d men i n t o a s i n g l e
p h y s i o l o g i c a l v a r i a b l e s u i t a b l e f o r guidance i n c o l d
weather p r o t e c t i o n o f o p e r a t i o n a l personnel. The SST
i s based on a simple t h e o r e t i c a l mcdel o f whole body
heat loss wherein the c l o t h i n g i n s u l a t i o n i s assumed
t o be impervious t o the wind and r a d i a t i o n exchange
between the s u r f a c e o f the c l o t h i n g and the e n v i r o n ment i s allowed f o r .
The wind a f f e c t s the thermal
i n s u l a t i o n o f the a i r l a y e r which c l i n g s to the o u t side c f the c l o t h i n g , changing i t s e f f e c t i v e thickness
by amounts which have been determined e x p e r i m e n t a l l y .
I t has been shown t h a t any dry environmental c o r d i t i o n
can be reduced t o one g i v i n g an equal r a t e o f heat loss
i n s t i l l a i r w i t h no r a d i a t i o n exchange, i n v.hich the
ambient temperature i s replaced by the SST, depending
on the metabolic r a t e and c l o t h i n g absorptance o f the
personnel i n v o l v e d . This paper describes the development o f a p o r t a b l e e l e c t r o n i c meter f c r ireasurement
o f the SST and the r e s u l t s t h a t have been a t t a i n e d
f o r i n i t s a p p l i c a t i o n t o working personnel i n c o l d a i r
environments.
14:30
DE5
Stable Isotope Abundances in Kidney Stones*, H.
R. KROUSE1 and A.A. LEVINS0N2, The University of~Calgary
— I n a continuing programme, mineralogically identified
kidney stones from a variety of geographical locations
are being examined to see (i) if their stable isotopic
compositions can be correlated to isotope abundances in
surrounding environments, and (ii) if isotopic selectivities can be identified which can be used to understand better the processes of kidney stone formation.
The carbon isotope abundances of uric acid and oxalate
stones tend to form two groups which fall approximately
midway between the isotopic compositions associated
with two of the earth's carbon reservoirs, marine carbonate and organic matter. The oxygen isotope composition of these stones appears not to follow meteorological preciptiation trends. The sulphur isotopic composition of cystine stones ranges widely with distinct
regional trends that are possibly related to sulphate in
surrounding waters.
•Supported by the National Research Council of Canada
and The University of Calgary Research Policy and
Grants Committee.
1
Department of Physics
department of Geology
15:30
DE8
Canadian Advances i n Heat Stress Instrumentation.
M. COWAN, L. KUEHN* and J . KR00N, Reuter-Stokes
Canada L t d . (RSCL) and «Defence and C i v i l I n s t i t u t e o f
Environmental Medicine (DCIEM). ~
Recent advances in
heat s t r e s s i n s t r u m e n t a t i o n technology have r e s u l t e d i n
new thermal p r o t e c t i o n standards f o r workers i n hot i n dustries.
This f a s t - r e s p o n d i n g and d i r e c t - r e a d i n g e l e c t r o n i c i n s t r u m e n t a t i o n measures the combined e f f e c t s
o f a i r temperature, h u m i d i t y , wind and r a d i a t i o n i n a
s i n g l e p h y s i o l o g i c a l index known as the Wet Bulb Globe
Temperature (WBGT). This paper describes several o f
the physical improvements r e s p o n s i b l e f o r the success
of t h i s technology such as " i n t e r n a l sensors" f o r measurement of dry and a s p i r a t e d wet bulb temperatures and
a small r a p i d - a c t i n g globe thermometer which has g r e a t l y decreased the measurement time and d i f f i c u l t y h i t h e r t o experienced i n t h i s f i e l d .
The l a t e s t development
c o n s i s t s o f a t e l e m e t r y system i n which heat s t r e s s
data i s t r a n s m i t t e d from hard hat mounted sensors t o a
r e c e i v i n g s t a t i o n f o r d e t e r m i n a t i o n o f the i n s t a n t a n eous and cumulative heat s t r e s s exposure o f the worker.
This system permits m o n i t o r i n g the heat s t r e s s exposure
o f several workers a t the same time and i s i d e a l f o r
w o r k - r e s t scheduling o f employee time i n l a r g e
industrial plants.
34
15:45
DE9 The Safe D i v i n g Envelope o f the Canadian Decompression Computer. R. BUCKLEY and L. KUFHN, DCTEM—
During the l a s t 15 y e a r s , a research and development
program a t the Defence 8. C i v i l I n s t i t u t e o f Environmental Medicine (DCIEM) has r e s u l t e d i n the successful
p r o d u c t i o n and c o m m e r c i a l i z a t i c n o f microprocessorbased p o r t a b l e and l a b o r a t o r y mounted d i g i t a l decompression computer f o r f a s t - and r e a l - time decompress i o n o f d i v e r s i n l a b o r a t o r y and f i e l d environments.
This paper describes the success o f t h i s computer t e c h nology i n p r e v e n t i n g decompression sickness throughout
the h i s t o r y o f t e s t i n g r.ow comprising some 2285 manexcursions i n approximately 10000 man hours o f t e s t i n g
t o depths as g r e a t as 340 f t (104 m) and times a t
bottom as long as 24 hours. This a p p r a i s a l has been
expedited by use o f a decompression data bank known as
Canadian D i v i n g Data (CANDID) and has r e s u l t e d i n
g u i d e l i n e s f o r the safe and expedient use o f such
computers which are now manufactured
Canada by
CTF Systems L t d .
16:00
DE10
Diffusion and Sedimentation of Aerosol Particles from Laminar Flow in Inclined Channels. CHENG-SHIH
CHEN, JEN-SHIH CHANG and J.G. LAFRAMBOISE, Centre for
Research in Experimental Space Science and Physics
Dept., York University, Toronto.— The theory of the
diffusion and sedimentation of aerosol particles from
Poiseuille flow in inclined channels has been done for
Intermediate Peclet numbers Pe, i.e. those for which
the effects of axial diffusion cannot be neglected.
Numerical results are presented for Pe from 0 to 100,
terminal settling velocity to flow velocity ratio 8
from 0 to 1, and angle 8 between channel axis and horizontal direction from 0° to ±90°. Numerical results
show that: (1) the effect of sedimentation on the
fractional penetration and deposition current at channel walls appears to be negligible when S S 0.01;
(2) significant axial diffusion effects are predicted
in aerosol concentration, fractional penetration, deposition current and percentage deposition. The possibility of making aerosol particle size distribution
measurements with diffusion batteries, using the
present theory, is discussed. The results also relate
to aerosol particle deposition in the trachea and
alveolar passages.
ATOMIC PHYSICS
TUESDAY, JUNE 13, 1978
ROOM 3024
Chairman: D. Paul
13:30
_
DFX
First Evidence for the Formation of pp and pd
Atoms.*t E.G. AULD and B.L. WHITE, Univ. of B.C.,
J. BAILEY, Daresbury Lab., G.A. BEER, Univ. of Victoria,
B. DREHER, E. KLEMPT, K. NEUBECKER, H. SCHWENK and
R. WODRICH, Univ. Mainz, H. DRUMM, U. GASTALDI and
R.D. WENDLING, CERN. - We have observed the Balmer
series of antiprotonic hydrogen and antiprotonic
deuterium atoms formed in hydrogen and deuterium gases
at 4 atmospheres pressure. The target consisted of a
pressure vessel of length 1.0 m and diameter 0.28 m.
The stop of the- antiproton vas defined by an array of
scintillation counters covering 100% of the solid angle.
The x-rays from the atomic transitions were detected by
a cylindrical proportional counter which surrounded the
target sas. The resolution of the countcr vac better
than 30% at 5 kev.
14:15
DF4
A b s o r p t i o n Spectra of Antimony and Bisiftuth
using the J»'laah Tyi-nlysis Technique. Y.N Joshi
and R.P Srivastava.iit.F.X.U
The absorption spectra of antimony and bismuth
have been observed in the region 1200A-2400A
on a 3-meter normal incidence spectrograph.
The absorption cell consisted of a flash pyrolysis system.and a Garton flash acted as a back
ground continuum source.The existing analyses
have been revised and extended. Many series
have been identified limiting on the first,the
second and the third ionization limits.some
Hi II lines were also observed,produced by the
photoionization of the bismuth atoms by the
pyrolysis flash.
•Experiment performed at the CERN proton synchrotron.
tSupported by the National Research Council of Canada.
13:45
DF2
Term Values of the Rvdberq Levels of Rubidiun.
E. VEINBERTFR and B.P. SIDICHEFF, Dept. Physics, Univ.
of Toronto.-Doppler-free, tvro-photon transitions in Rb
were observed frcm the ground state up to high 2 F and
2
D Rydberg levels (with n>60, and only a few wavemmbers below the ionization limit) using cw dye laser radiation and a sensitive thermionic detector. Term values
vere determined by measuring the laser wavelengths to
an accuracy of 1 part in 10° using a wavaneter. As expected for a one electron system, the term values for
each series could be accurately represented by a simple
expression including ionization limit and quanttn defect. Doth series lead to an ionization limit for 8 5 Rb
1
lower than
of 33,690.853+0.005 cm" 1 , about 0.2 cm
earlier values.
14:00
DF3
Laser-Induced Fluorescence Study of 6 ' 7 L1 II.
S.D. ROSNER and R.A. HOLT, Univ. of Western Ontario.—
The Li atom is of great importance in our understanding
of two electron systems. Observations of the 2s 3 S 2p 3P transition using laser induced fluorescence on an
ion beam will be discussed with a view to extracting
more accurate values of the fine and hyperfine constants
•for comparison with theory.
14:30
Multlconfiguration Optimized Effective Central
D P5
Potential Method for Atomic Calculations.* K. AASHAMAR ,
T.M. LUKE, J.D. TALMAN, Univ. of Western Ontario.— In a
recent paper1 an optimized effective central potential
method has been outlined for atomic structure calculations assuming a single-configuration, single-determinant
approximation to the total wave function. The procedure
involves an averaging over angular momentum and spin
states, and thus the calculated quantities represent
averages over all terms SL resulting from the configuration concerned. In the present work we consider the
problem of generalizing the method into a fully symmetryprojected multiconfiguration expansion approach using the
SL coupling approximation. Preliminary calculations of
ground state energies for a number of elements show a
relative difference between our values and corresponding
multiconfiguration Hartree-Fock results of the order of
10-50 ppm, a difference which generally tends to decrease
with Z.
1
J.D. Talman and W.F. Shadwick, Phys.Rev.A14, 36(1976).
•Supported by the National Research Council
tOn leave from University of Oslo,Oslo, Norway.
35
14:45
DF6
Absence of Universal Local EffectivePotentials for Atoms.* J.D. TALMAN, Univ. of Western
Ontario.—
It has been shown by Hohenberg and Kohn 1
that the energy of a system of electrons Is a functional
of the electron density. This result has prompted
various authors to propose local density models for
atoms in which exchange and correlation effects are
accounted for by introducing a local effective
potential which is some function of the density. In a
recent article 2 a method has been described for
calculating a variationally optimized local exchange
potential for atoms. The behavior of these potentials
as functions of density cannot be described by any
universal model. However, the Xa model, with a - 2/3
and 1,seems to provide approximate upper and lower
bounds.
1
P. Hohenberg and W. Kohn, Phys. Rev. 136B, 864 (1964).
2
J.D. Talman and W.F. Shadwick, Phys. Rev. A14, 36
(1976).
* Supported by the National Research Council.
15:00
DF7
K-Shell Ionization following Proton Bombardment. M.S.A.L. AL-GHAZI, J. BIRCHALL, J.S.C. MCKEE,
W.D. RAMSAY and N. VIDELA, Cyclotron Laboratory, Univ
of Manitoba~
_
-The
subject of characteristic x-ray
emission induced by bombarding protons of 20-50 MeV
energy is discussed. An attempt is made to understand
the K-shell ionization process and the x-ray emission
following it in the light of existing theoretical
models and the experimental data presented in this
paper.
15:15
DF8 T o w n s e n d D r i f t of P o s i t r o n s in G a s e s .
J .S . T S A I and D . A . L . P A U L
U n i v . of T o r o n to
The d r i f t of p o s i t r o n s mo v i n g in g a s e s su b j ect
to a u n i f o r m e l e c t r i c fie Id (E) h a s b e e n o b s e r v e d £or h e l i u m , n e o n , a r g o n , n i t r o g e n and
me tha ne ; by d r i f t i n g an i n i t i a l l y u n i f o r m
p e n c i 1 of s l o w p o s i t r o n s t o w a r d s an a n n i h i l a t i o n t a r g e t and c o u n t i n g a n n i h i l a t i o n p h o t o n s
in co i n c i d e n c e , u s i n g fin e s p a t i a l r é s o l u tion .
T h e d a t a for h e l i u m h a v e b e e n a n a l y s e d us ing
a s im pie n e w f o r m u l a w h i c h i n c l u d e s the e f f ec t s of d r i f t and l o n g i t u d i n a l d i f f u s i o n
P o o r a g r e e m e n t w i t h t h e o r y h a s led to imp r o v e m e n t s in the a p p a r a t u s w h ich h a v e n o w b e e rt
compl eted.
We h a v e c o m p u ted p o s i t r o n i u m f o r m a t i o n e n h a n c e m e n t s at the
higher E-values
(e +H e + ( e e ) + H e ).
Our
d a t a i n d i c a t e th e onset o f an a n a l o g o u s p r o c e
ss at l o w e r E - v a l u e s
than p r e d i c t e d , s u g g e s t i n
g p o s i t r o n i u m fo rma tion in e
collisions wi
th the a n n i h i l a t i o n
targe t -- such f o r m a t i o n
is e n e r g e t i c a l l y po s sible
E x p e r i m e n t s u ^ i n g the i m p r o v e d eq u i p ment
and a s t r o n g e r e
so u r c e are in p r o g r e s s .
1. J .S
. T s a i and D . A . L . Paul. 1 9 7 7 . A b s t r a c ts
of X
I . C . P . E . A . C . (Paris) 2, 828-9
15:30
The Dépendance of Electronic Recombination on
D F9
the Type of Capture Orbital in the Molecular Ion. V.S.
D'ANGELO, P.MUL, P.DEFRANCE*, J.B.A.MITCHELL**, H.R.
FROELICH, J.KEYSER and J.W.McGOWAN,Univ. of Western
Ontario.—Electron-ion recombination cross sections for
various diatomic and polyatomic molecules have been
measured for energies ranging from 0.03 eV to = 5.0 Ev
in merged electron-ion beam experiments. For some
molecular ions the cross section dépendance conforms to
the standard 1/E dépendance over the entire measured
range. For others the dépendance charges, at some
energy E Q , to a 1/E n dépendance where n > 1. Examples
of molecular ions which seem to fall in the first group
are H 2 + , C H 2 + and CH+. Others such as H 2 0 , H 3 0 , C H 3 +
and NHi, seem to be members of the second group. It
appears that when the lowest energy orbital in the
ground state of the molecular ion, into which the electron can be captured, is a bonding orbital, then the
energy dépendance of the cross section is 1/E over the
entire measured energy range. If, however, the lowest
energy orbital is a non-bonding or anti-bonding orbital,
the 1/E dépendance changes to a 1/E dépendance as some
energy E Q within the range. Supported by USDOE.
*Visitor from Louvin-la-Neuve, Belgium under NATO support
**Now at Brookhaven National Laboratory.
15:45
DFi0
On the Charge Transfer to the Continuum
Theories and Experiments.* K.C.R. CKIU and
J.Wm. McGOWAN, Univ. of Western Ontario.—v e ~ vi
electron from ion-atom collisions come from at least
two sources: direct ionization of the target and
charge transfer to the continuum (CTC) of the projectile.
All CTC theories include both sources and consequently
predict quantum mechanical interference in the electron
production double differential cross sections. Though
we have carried out an exhaustive search for such interference, none has been found. This confirms the results
of Duncan et al 1 and suggests that one can treat ionization as a "background1 as we examine in detail the
CTC process. The |ve - VjJ - 1 dependence predicted by
all CTC theories is supported. 2 Details of the
theories and experiments will be discussed.
*Supported by N.R.C. and the U.S. D.O.E.
1
Duncan, M.M., Menendez, M.G., Eisele, F.L. and Macek%J.
Phys. Rev. A15, 1785, 1977.
2
Chiu, K.C.R., McGowan, J.Wm., and Mitchell, J.B.A., to
appear in J. Phys. B. (Lett.)
16:00
DFl^.
e-ion t Recombinat ion of Astrophysical Importance I CH
CH 5 . J.B.A. MITCHELL*, P.MUL, V.S. D'ANGELO,
J.W. McGOWAN, Univ. of Western Ontario.— Attempts by
astrophysicists to produce models for the formation and
destruction of molecules and molecular ions in interstellar clouds have been frustrated by the lack of reliable experimental data. The rate coefficients used in
modelling too often are at best educated guesses.
In a
merged electron-ion beam experiment METBE we have studied electron-ion recombination with small hydrocarbon
ions CH +
CH 5 . We have found in all cases that the
rate constants are large and of the same magnitude. In
the case of CH + this finding is in contradiction with
some theoretical estimates and at odds with much of the
now accepted modelling.
In this case the rate coefficient at 100K (O.OleV) is 3 + 0.3 x 10~ 7 cm 3 sec"1 with a
temperature variation of T - (» • ± o . i ) _ This W O r k is
supported by NRC in conjunction with the USDOE.
*Present address Brookhaven National Laboratory.
16:15
DF12
II Ho*.
o"" • ^ P ^ M U L ^ J .^B?A? ^M^TCHELL* , Lp?^DF.FRANCE*
V.S. D'ANGELO, J. KEYSER, J.W. McGOWAN, Univ. of Western
Ontario.
One of the most important problems associated with developing a theory to describe molecular formation in insterstellar clouds is the calculation of the
(II/D) ratio and the electron density within the clouds.
To assist with this modeling we have applied the MEIBE
methods to measure electron-ion recombination cross
sections for all isotopic combinations of H and D in
H 2 + and H3 + systems and have identified for both H? + and
H 3 + a significant isotope effect. Our measurements of
cross sections and rate constants extended from belOw
O.OleV to above 2eV.
This work is supported by NRC and the USDOE.
*present address Brookhaven National Lab.
**visitor from Louvain-la-Neuve, Belgium under the
support of NATO.
36
TUESDAY, JUNE 13, 1978
ROOM 3026
Chairman:
I . K . MacKenzie
13:30
DG1
Temperature-dependent Positron Trapping In
Electron-irradiated Nickel."^ J. A. JACKMAN, C. W.
SCHULTE and J. L. CAMPBELL, Univ. of Guelph—The
Doppler-broadened annihilation lineshape has been
measured between 80 and 320 K for nickel irradiated with
5 MeV electrons. Finite temperature dependences are
observed for 50% and 100% positron trapping, implying
that either or both of the capture rate per vacancy and
the "trapped lineshape" may have small T-dependences.
Divacancies appear to be implicated in these effects.
* Supported by the National Research Council
13:45
Color Centers in Irradiated Sodium Chlorate.V.S. SIVASANKAR and P W. VHIPPEY, Univ. of Western
On tar io.—Single crystals of sodium chlorate have been
grown from saturated aqueous solution. The crystals
have been subjected to x-irradiation (30 kV, 15 mA) for
different durations both at 77 K and 300 K. Thermoluminescence glow curves recorded from 77 - ^00 K show
a minimum of three prominent peaks at 173, 191 and
249 K. In an attempt to arrive at the structure of the
centers responsible for these glow peaks, optical
absorption spectrum of the radiation damaged crystals
has been recorded in the range 250 - 700 nm, as a
function of radiation dose, at different stages of
thermal annealinq. The spectrum consists of two broad
regions of absorption peaking at about 400 and 300 nm.
The variation with temperature of the optical spectrum
has been found to be complex. Similar studies using
electron spin resonance technique gave evidence of the
presence of at least three paramagnetic radicals (CIO3,
C102. 0,") at 77 K. Their parameters agree with those
reported by others. The changes in optical absorption
and/or ESR spectrum with temperature have been correlated with the temperature of the glow peaks and
models have been proposed for the luminescent centers.
•'Supported by N.R.C. £ Centre for Chem. Phys., U.W.0.
POSITRONS, DIFFUSION, DAMAGE, IMPURITIES
14:15
DG4
Temperature Dependence of Positron
Annihilation in Ice* R.J. DOUGLAS, L. LUPTON and A.T.
STEWART Queen's University and M. ELDRUP Riso National
Laboratory. Denmark—Angular correlation measurements
were made in single crystals of ice I in the temperature range 4-160 K. At temperatures below 60 K, radiation damage from the 58 Co positron source was observed
by the diminution of the amplitude of the narrow zeromomentum positronium peak. The recovery of this radiation damage was observed at higher temperatures, and
the amplitude recovery was complete by 110 K. The
width of the zero-momentum positronium peak was measured at high resolution (.1 to .25 mrdd), and the
temperature dependence of the effective mass of positronium in ice was determined. These results will be presented and discussed.
•Supported by NRC.
14:30
DG5
Vacancy Formation Energies in Nl, Fe, Co, V and
Cr by Positron Trapping.
C. W. SCHULTE, J. A. JACKMAN
and J. L. CAMPBELL, Univ. of Guelph—The Dopplerbroadened lineshapes for Ni, Fe, Co, V and Cr have been
measured between 300 and 1900 K using an inert gas
positron source circulating through tubular specimens.
Data are analysed via the trapping model and in terms of
threshold temperatures T t . Empirical linear relationships between T t and both vacancy formation energy and
self-diffusion activation energy are discussed.
*
Supported by the National Research Council
14:45
14:00
DC3
Helium Irradiation Effects in Copper at ~20keV.
B. TERREAULT, J.G. MARTEL and R.G. ST-JACQUES, INRSEnergie, Univ. du Quebec.— Surface blistering has
been observed by scanning electron microscopy; blister
density, size and skin thickness have been measured as
a function of fluence, energy, and material preparation.
An ion-beam technique has been developed to measure
with a - 300 8 accuracy the depth distribution of the
helium. The distributions are correlated with theoretical ranges, with the skin thickness measurements,
and with measurements of gaz reemission^ ' and swelling^). In particular a surprising double-peaked
distribution is discussed in terms of current blistering models. The data favor the "gas pressure" model.
1
e.g. K.L. Wilson and G.J. Thomas, J. Nucl. Mater.
63, 266 (1976) .
2
R.G. St-Jacques et al., in preparation.
1)06
Positron Diffusion in Metals and Trapping at
Grain Boundaries*. B.T.A. McKEE, Queen's Univ.. and
G.J.C. CARPENTER, F.J. SCHULTZ and J.F. WAITERS, AECL.
Chalk River. —
The diffusion of positrons in metals
is of both fundamental and practical interest due to
the connection with positron scattering and to its role
in limiting positron trapping at defects. We have performed measurements of the positron trapping rate in a
series of fine-grained Zn-22 at % Ai alloy specimens
with mean grain diameters ranging from 0.38 to 1.9 pm.
Positron trapping is observed to increase with decreasing grain size. Interpreting the data in terms of
motion limited trapping at the grain boundaries1 yields
a diffusion constant D = 0.53 cm2/s for positrons in
this alloy at 292 K and a diffusion length of .13 ym,
in close agreement with theoretical predictions.2 The
trapped positron lifetime is about 250 ps, implying that
open spaces larger than monovacancies are not available
at the grain boundaries.
^W. Brandt and R. Paulin, Phys. Rev. B
2I130 (1972).
B. Bergersen, E. Pajanne, P. Kubica, M.J. Stott and
C.H. Hodges, Solid St. Commun. IJj, 1377 (197L).
•Supported in part by N.R.C.
37
15:00
DG7
Diffusion of light interstitials in solids.
T. MC MULLEN, Queen' s U. , and B. BERGERSEN, U . B . C . —
Experimental data on the diffusion of the
hydrogen isotopes H, D and T in metals have frequently
been analysed in terms of the classically expected behaviour of the diffusion constant D = D exp(-E /It T).
There are, however, some indications that the classical
theory is inadequate. In addition, recent experiments
on positive muon spin depolarization have yielded data
on the motion of the considerable lighter u+ , for which
any quantum mechanical aspects are expected to be
exaggerated. Following a brief summary of the experimental data, a theory of the motion of light interstitials in solids via tunneling in a single narrow band
will be presented. The theory includes the distortion
of the lattice around the interstitial, and this can
cause the motion to be strongly temperature dependent.
Both coherent and incoherent tunneling processes are
considered. This theory differs from earlier work in
neglecting the response of the interstitial wavefunction
to the self-trapping distortion, giving a simplified
treatment in which all quantities are well defined and
in principle available from microscopic calculations.
15:30
DG8
Self Diffusion Measurements in the Superionic
Agl9llsP207 at the Second Order Phase Transition.
M. SAYER. E. PRASAD and J. COREY, Queen's Univ.,
Kingston, O n t . — T h e superionic solid electrolyte
AgigIi 5 P 2 07 which has a room temperature conductivity
of 0.07 fi'lcm-1 has recently been shown to have a
second order phase transition at 223°K. Diffusion
constants determined from self diffusion measurements
above and below the transition temperature are used
in the Einstein relation to determine Ag mobilities
at these temperatures. Employing a
simple
hopping process carrier concentrations are determined
at these temperatures and are used to describe the
physical basis of the second order phase transition.
TUESDAY, JUNE 1 3 , 1978
ROOM 2036
Chairman:
P.W. Whippey
16:15
DH1
R i p p l e s i n Space-Time.
P. D.
L0LY, U n i v . o f
M a n i t o b a - A c o m p l e t e t r i g o n o m e t r i c development o f
c i r c u l a r and s i m p l e harmonic m o t i o n i s e x t e n d e d t o t h e
s p a t i a l domain.
S i m u l t a n e o u s s p a t i a l and t e m p o r a l
o s c i l l a t i o n s r e s u l t i n p r o g r e s s i v e waves f o r w h i c h o u r
approach suggests a r e p r e s e n t a t i o n i n terms o f c o r r u gations ( r i p p l e s ) in a space-time p l o t .
An a l g e b r a i c
analogue o f t h e p a r t i a l d i f f e r e n t i a l wave e q u a t i o n
r e a d i l y y i e l d s t h e speed o f p r o p a g a t i o n o f waves.
The
method commends i t s e l f t o a s o l i d t r e a t m e n t o f t h e
t o p i c s m e n t i o n e d w i t h o u t t h e u s u a l dependence on
c a l c u l u s and y e t i s r e a d i l y c o n v e r t e d t o t h a t l a n g u a g e
when s t u d e n t s have a c q u i r e d s u f f i c i e n t w o r k i n g a b i l i t y .
16:30
DH2
Annual Business Meeting
15:45
DG9
Nonthermal Slow positron Emission fro» hg<J.
S.PENDYALA and J.Wm. McGOWAN, Dept. or Physics and
Center for Chemical Physics, U. of Western Ontario.
— Magnesium oxide on gold vanes is commonly used
aa a moderator in producing slow positrons.' Unlike
many metallic moderators the slow positron spectruœ
from MgO i6 wide (1eV) and the intensity doesnot
decrease except the peak shifts by nearly leV.2
The results suggest that the slow positrons from
MgO are nonthermal. The absorbed and adsorbed water
mai have caused a shift in the peak upon heating
but the higher intensity from MgO is probably due
to voids in the pow der rather than due to the
presence of water. We may conclude that thsre are
perhaps a multitude of processes which might cauee
the emission (or d i f f u s i o n ? ) of slow positrons
from solids.
'K.F.
2
Canter et al., Phys. Rev. Lett.
S.Pendyala
Supported
et al., Can.J.Phys.
1527
7
(1973).
(1976).
by National Research Council of Canada.
16:00
DG10
Multiple Components in Slow Positron
Spectra from Metallic Moderators with unclean
Surfacea. S.PENDYALA and J.Wm. McGOWAN, Dept. of
Physics, U. of Western Ontario.-- tarlier it was
reported that heating some (water cleaned)
metallic moderators to several hundred K results
in the loss of slow positron intensity.! Further
observations revealed that the spectra consist of
two components labelled here as I and II. The loss
of intensity is found to be due primarily to the
decrease in component I. The two sets of data
(before and after h e a t i n g ) from Cu are fitted with
two Gausslans of FWHM 0.l»eV(I) and 0 . 7 e V ( I I ) and
peak h e i g h t s 50 and 12 with peak separation of
0.7eV before heating and peak heights 30 and 12
after h e a t i n g respectively. This analysis suggests
that component I is produced through positroniun
dissociation involving complex charge transfer
reaction requiring the presence of only few atomic
layers of physisorbed water and component II is a
q u a s i e q u i l l i b r i u m distribution of slow positrons
inside the metal which overcome the surface
barrier.
] s . P e n d y a l a et al., Can.J.Phys.
1527 ( 1 9 7 6 ; .
'Supported by National Research Council of Canada.
DIVISION OF PHYSICS EDUCATION
38
WEDNESDAY, JUNE 1 4 , 1978
ROOM 2024
Chairman: D.R. T a y l o r
9:00
EA1
PHASE TRANSITIONS AND MOLECULAR SOLIDS
The Percolation Threshold in Random and Non-Random Systems
S. REDNER, UniveAAity
Tcionto
The main physical features of the percolation problem are introduced. This phenomenon deals with
particular geometric properties of clusters that occur in random systems. For example, if a fraction
of the squares in a checkerboard are randomly occupied with checkers, then as the concentration is
increased to a certain value, an infinite cluster of particles appears. The analogy between the
geometric features of clusters near this percolation threshold and the critical phenomena of a
ferromagnet near a second order phase transition will be described. An interesting generalization
of percolation, allowing for correlations between neighbouring particles, causes the details of
the percolation threshold to change. An example of such a non-random problem is spin clusters in
the Ising model. The relationship between the percolation threshold and the ferromagnetic phase
transition in this system leads to some important open questions which will be discussed.
9:45
EA2
Rotational Phase Transitions in 5d Transition Metal Antifluorite Crystals
R.L. ARMSTRONG, UvUvVUxUy 0^ Toiowto
Many crystals which possess the cubic antifluorite structure at room temperature, exhibit one or more structural
phase transitions as the temperature is lowered. Magnetic resonance, neutron scattering, specific heat and
thermal expansion data have been obtained for several 5d transition metal compounds in the vicinity of these
transitions. These data have indicted two distinct types of transitions, both of which involve the correlated
rotational motion of MX5 octahedral units. In the one case the equilibrium positions of the MX5 molecules
are rotated from their positions in the high temperature phase. The soft mode has been observed to be a
rotary lattice mode. There is evidence for non-mean field behaviour near T c and the presence of cluster waves
has been inferred. In the other case very few data are available. Nonetheless, it seems certain that the
equilibrium positions of the MXg molecules are not rotated. A model has been proposed to account for the
nature of the observed transitions.
10:30
EA3
The Plastic-to-Normal Phase Transition in Molecular Crystals
G. DOLLING, Chalk RivzA hiucliaA
LaboMUoiieA
Many molecular crystals exhibit high temperature phases characterized by a substantial degree
of molecular orientâtional disorder. The nature and extent of this disorder and the changes which
occur on cooling through the phase transition to the so-called "normal" crystalline phase, may be
studied by X-ray and neutron scattering techniques. A wide variety of behaviour has been observed
for such plastic crystals as adamantane, carbon tetrabromide, cyclohexane, methane, nitrogen and
sulphur hexafluoride, but specific mechanisms for the plastic-to-normal crystal phase transition
have been proposed in only one or two cases.
11:15
EA4
Orientation Ordering and Nuclear Conversion in Solid Methane
J.A. MORRISON, McMcuteA UYUWibiXy
In solid methane, orientational ordering introduces surprising complexity into the physical
properties of the solid at low temperatures (T<30K). The complexity is compounded by the
occurrence of conversion between nuclear spin symmetry species at a rate that is extraordinarily
sensitive to the structure of the solid and to the presence of a catalyst1""3. Nevertheless, the
example of CH^ is now reasonably well understood within the framework of the extended James and
Keenan model4. Similar understanding has not yet been achieved for the deuterated methanes.
Recent calorimetric and neutron cross-section experiments on CH3D and CH 2 D 2 will be described.
The results lead to the conclusions that complete orientational ordering does not occur in the
lowest temperature phase of either isotopic methane, even at temperatures as low as 0.12K.
l
R.F. Code and J. Higinbotham, Can.J.Phys. 54,1248(1976).
K.J. Lushington and J.A. Morrison, Can.J.Phys.55,1580 (1977).
A.J. Nigman and A.J. Berlinsky, Phys.Rev.Lett.38,408 (1977).
U
T. Yamamoto, Y. Kataoka and K. Okada, J.Chem.Phys. 66,2701(1977).
2
3
39
APPLIED PHYSICS EDUCATION
WEDNESDAY, JUNE 1 4 , 1 9 7 8
ROOM 2 0 5 0
Chairman:
W.D. Westwood
9:00
EB1
9:30
EB2
Physicists for Canadian Industry
M.P. BACHYNSKI, M.P.B. Technologies
Inc.
Observations on Applied Physics Education in the U.S.
R . C . IVEY, Abilene
Christian
University
Applied or engineering physics programs exist in over 100 universities in the U.S.A. The wide range of
models almost mimic fermion statistics, each claiming differences. Questions concerning curriculum,
purpose, accreditation and usefulness are continually raised. Most new programs were spawned from a
depressed era beginning in the late 1960's as a response to economic and employment problems. Today,
most students must seek industrial jobs although the attitude of many industries toward physicists is
not enthusiastic. Problems with faculties unwilling or unprepared to consider physics as a training
program for industrial employment are understandable, but it would be in the best interests of our
discipline to do away with any stigmas attached to applied physics. Some attitudes of industry,
faculty, and students will be presented to focus attention on problem areas.
10:00
EB3
Engineering Physicist - Engineer, Physicist or Neither?
M. SAYER, Queen'6
University
Canada has a long established tradition of undergraduate Engineering Physics programmes at a number
of universities. Recent developments within the engineering profession have placed more stringent
requirements on the curriculum with respect to its acceptability for professional registration. The
pros and cons of registration requirements will be discussed along with results of surveys of the
careers of graduates from the programmes. The substantial increase in enrolment in engineering
physics in recent years indicates at least a student appreciation of the need for more applied
physics in Canada.
10:30
EB4
Spending a Sabbatical Leave in Industry
R . R . PARSONS, University
of BnUXlsh
Columbia
Recognizing the need for closer university/industry liaison is not enough.
It is
important for university faculty to become more directly involved in the scientific and technical problems of industry. If scientists in Canadian universities
want to keep abreast of the market for students and to bring their teaching
methods and research into line with current industrial requirements, they should
consider spending a sabbatical leave in a Canadian industry. This is an excellent
opportunity to establish personal contacts in industry and to acquire some
industrial experience so as to benefit teaching, curriculum planning, student
counselling and applied research. The speaker has just spent a sabbatical year at
Bell Northern Research, with support from a NRC Senior Industrial Fellowship. He
would like to describe his experience and to make recommendations for further
development of the NRC Fellowship program and to suggest ways to encourage
academics to spend at least part of their sabbatical leave in industry.
11:00
EB5
Panel Discussion on 'Education of Applied Physicists in Canada'
M.P. BACHYNSKI, R. PARSONS, M. SAYER, R.C.IVEY
40
WEDNESDAY, JUNE 1 4 , 1978
ROOM 2036
Chairman:
W. M c L a t c h i e
9:00
EC1
NUCLEAR PHYSICS
Search for Weak Neutral Currents in Nuclei*
R.G.H. ROBERTSON, Michigan
State
University
Although the existence of a weak neutral current is now beyond question, its detailed nature, and in particular
whether or not it violates parity, remains uncertain. The presence of a parity-violating hadronic weak neutral
current may be revealed in nuclei in the form of an appreciable ûT=l parity non-conserving effective interaction.
Such an interaction would permit the alpha-decays of the O ^ T ^ l state at 3.56 MeV in 6 Li and the 1 + ,T=1 state
at 11.26 MeV in 2 0 Ne. A progress report on experimental searches for these decays, and on other nuclear
physics experiments with similar aims, will be presented.
•Research supported by the U.S. National Science Foundation.
9:45
EC2
Recent Progress in Weak Interaction Experiments at TRIUMF
H. HASINOFF, University
of British
Columbia
The unified gauge theory of the weak and electromagnetic interactions, first proposed by Weinberg
and Salam in 1967, has been remarkably successful in its predictions of a weak neutral current in
vN scattering and the existence of the charmed quark. However, the recent discovery of heavier
charged (and neutral?) leptons along with the failure of the model to predict the level of parity
violation in the Bi atomic physics experiments has led to several extensions of the original W.-S.
model in the past two years. Several of the weak interaction experiments1 currently underway at
TRIUMF can be used to constrain the various extended theories. New results from the rare decay
experiments
and ir-*«ve will be presented along with a progress report on the muonium, antimuonium conversion experiment (iAe~ -*• u~e ).
Experiments performed by various groups from U.B.C., Université de Montréal, and Univ. of
Victoria.
10:30
EC3
11:15
EC4
Measurement of G-Factors for Rotational States Using the Enhanced Transient Field Interaction
D. WARD, Chalk Hiver Nuclear
Laboratories
Phenomenology of Nuclear Inclusive Reactions at Medium Energy
R.M. WOLOSHYN, TRIUMF and University
o( British
Columbia
Recent experimental and theoretical work on nuclear inclusive reactions will be reviewed. Experimental data supporting the hypothesis of quasi-two-body scaling1 will be presented. 2
It is
suggested that the measurement of semi-inclusive quantities such as the average multiplicity of
nucléons produced in coincidence with energetic backward-going protons car. help to determine the
mechanism for nuclear inclusive reactions. This will be discussed within the framework of a cluster
recoi1 model.
1
2
S. Frankel, Phys. Rev. Lett. 38, 1338 (1976).
S. Frankel et al., submitted to Phys. Rev. C.
41
WEDNESDAY, JUNE 1 4 ,
ROOM 2 1 1 0
Chairman:
J . Hunt
9:00
EDI
UPDATE ON IMAGING
1978
Diagnostic Ultrasound
A . GOLDSTEIN, Henny Void.
Hospital,
VoMott
U l t r a s o u n d i m a g i n g i s a r a p i d l y g r o w i n g a r e a i n d i a g n o s t i c m e d i c i n e due t o i t s a b i l i t y t o
v i s u a l i z e s o f t t i s s u e s t r u c t u r e s w i t h v e r y low b i o l o g i c a l r i s k to t h e p a t i e n t .
Ultrasound
i m a g i n g f i r s t d e v e l o p e d as a p r e f e r r e d m o d a l i t y i n OB-GYN e x a m i n a t i o n s a n d now i s f i n d i n g
i n c r e a s e d use i n i m a g i n g o t h ° r a r e a s o f t h e b o d y i n c l u d i n g : a b d o m i n a l o r g a n s , r e a l t i m e
c a r d i a c s t u d i e s , s u p e r f i c i a l organs ( t h y r o i d ) and p e r i p h e r a l v a s c u l a r d i s e a s e .
The p r i n c i p l e s o f u l t r a s o u n d p r o p a g a t i o n i n s o f t t i s s u e w i l l be d e s c r i b e d .
The d i s c u s s i o n w i l l
i n c l u d e : g e n e r a t i o n o f u l t r a s o u n d p u l s e s , pulse-echo d i s t a n c e measurements, r e s o l u t i o n ,
attenuation,
r e f l e c t i o n , r e f r a c t i o n , a s s u m p t i o n s made i n d a t a h a n d l i n g , u l t r a s o u n d d a t a
p r o c e s s i n g and image a r t i f a c t s .
The c l i n i c a l a p p l i c a t i o n s o f u l t r a s o u n d i m a g i n g w i l l be
r e v i e w e d w i t h e m p h a s i s on t h e r e q u i r e d i n s t r u m e n t a t i o n .
T y p i c a l c l i n i c a l i m a g e s w i l l be
p r e s e n t e d f o r each c l i n i c a l a p p l i c a t i o n .
P o t e n t i a l h a z a r d s ( b i o e f f e c t s ) w i l l be summar i z e d and p r e d i c t i o n s o f f e r e d i n t o t h e f u t u r e o f u l t r a s o u n d i m a g i n g .
9:45
ED2
The Focussing of Ultrasound Beams Through Human
Tissue. F.S. FOSTER and J.W. HUNT, Ont. Cancer Inst.,
and Dept. of Medical Biophysics, Univ. of Toronto.- In a
homogeneous medium, a transducer can be focussed to a
small spot: the lateral spatial resolution, 6, at the
focus is limited by the Fraunhofer diffraction equation,
6 = 1.22Az/d = 1.22A(f-number) in which z is the focal
length, A the wavelength, and d the diameter of the
transducer.
As a focussed ultrasound wavefront converges
in tissue, each point of the wavefront experiences v e ocity fluctuations due to the structure and composition
of the tissue at that point.
This results in beam steering and spreading of the ultrasound distribution at the
focal zone.
Using a variable aperture transducer (50
mm m a x ) coupled to a unique variable focal-length lens,
the beam 3pread has been studied for various tissues.
Focal distributions were studied using a 0.8 mm diameter
microphone.
For liver, it has been found that 6 increases
linearly with f-number, and increasing tissue thickness.
For some tissues such as male breast, some nonlinear effects were found.
Large apertures (low f-numbers) consistently provide a more stable focus than the small
apertures, and are less susceptible to beam steering.
Studies of female breast tissue are in progress, and
preliminary results will be reported.
10:00
ED3
Ultrasonic Properties of Bone.
B. J. GARCIA,
K. G. McNEILL, R. S. C. COBBOLD and F. S. FOSTER,*
Inst, of Biomed. Eng., Univ. of Toronto and Ont. Cancer
Inst.-Ultrasound holds promise as a means of obtaining
clinically useful information concerning the density
and elasticity of bone tissue.
Experiments have been
conducted in an attempt to relate basic ultrasonic
parameters, I.e., reflection and transmission coefficients, velocity and attenuation to the mechanical
properties of bone.
Two modes of wave propagation,
longitudinal and shear, were measured by a transmission
technique.
By measurement of critical angles the
Young's modulus and shear modulus were determined to be
E « 15.26 x 1 0 9 N/n>2 and G = 5.78 x 1 0 9 N / m 2 , respectively, in normal bovine bone.
Ultrasonic attenuation
is measured using broad-band pulse transmission, and
off-line computer analysis.
Attenuation was studied
as a function of bone mineral content. At 5.0 MHz, the
attenuation in normal bovine bone, and fully de-calcified bone was 31 dB/cm and 5 dB/cm respectively.
* Ontario Cancer
Institute.
10:30
Recent Developments in CT Scanning.
M. YAFFE
ED4
and H. E. JOHNS, Ont. Cancer Inst.-Computed tomography
(CT) is a technique for producing cross-sectional
images of the human body from a large set of "narrow
beam" x-ray transmission measurements.
A digital
computer is used to reconstruct a matrix of linear
attenuation coefficients corresponding to the anatomy
in the cross section.
The images are of moderate
spatial resolution (1 line pair/mm) and exhibit excellent contrast sensitivity (.51%).
Since the commercial
introduction of CT in 1972 many refinements have taken
place that have improved the quality of the images.
In
this talk the physics of CT scanning will be outlined
and the development of modern scanners will be
discussed.
11:00
ED5
Quantitative Determination of Electron Densities
and Atomic Numbers in C.T. Scanning. A. FENSTER, Ont.
Cancer Inst.-In CT scanning, the physical quantity
measured is p, the total linear attenuation coefficient.
Additional diagnostic information would be available if
the Compton o and photoelectric coefficients T could be
calculated from u since the electron density of the
tissue is proportional to a and the atomic number is
related to x. The electron density is of importance in
radiotherapy treatment planning calculations while
knowledge of the atomic number allows tissue characteri2
ation.
One can obtain electron density and atomic number from scans using two different x-ray spectra or by
using detectors which provide energy selection.
A
method employing a dual xenon ionization detector is
described.
In this device the front portion of the
chamber measures soft radiation which is mainly influenced by the photoelectric processes in the tissue,
while the rear portion measures primarily hard radiation
associated with the Compton process.
11:20
CT Scanning in Precision Radiation Therapy.
ED6
M. J. BRONSKILL and J. J. BATTISTA, Ont. Cancer Inst.
Quantitative transverse section images from CT scanners
have great potential for improving the accuracy of
radiation therapy treatment planning.
Advanced computerized treatment planning systems can now use the
patient contour and tumour location information obtained
from a CT scan, provided the identical patient position
is maintained for both scanning and treatment. The
advantages of good spatial resolution and tumour location accuracy can be lost, however, unless the problems
of interpreting tissue density from CT numbers and
overcoming errors due to patient respiratory motion are
solved.
42
WEDNESDAY, JUNE 1 4 , 1 9 7 8
ROOM 3 0 2 2
Chairman:
A . G . McNamara
9:00
EE1
A model current system for magnetosphere-ionosphere
coupling at high latitudes - the substorm component.
G. ROSTOKER and T.J. HUGHES*, Dept. of Physics, University of Alberta — A model current system involving
field-aligned and ionospheric current flow has been developed to explain the magnetic perturbation pattern
observed at high latitudes during periods of moderate
activity. This model has been modified to include the
development of the substorm westward electrojet. Detailed model studies permit the simulation of the substorm perturbation pattern in the vicinity of the westward travelling surge. It is found that the Pedersen
conductivity must be enhanced at the western edge of
the surge in order to account for the observed magnetic
perturbation pattern.
*now at Radiological Research Laboratories, University
of Toronto, Toronto, Canada
9:15
EE2
A Theory f o r the Enhancement o f Ionospheric
Irregularities.
J . W. MacDougall, Univ. o f Western
O n t a r i o - - Some o f the behavior p a t t e r n s o f mid
l a t i t u d e spread F w i l l be reviewed.
I t w i l l be shown
t h a t present t h e o r i e s f o r spread F do not give agreement w i t h these behavior p a t t e r n s .
A mechanism whereby i r r e g u l a r i t i e s are enhanced
i n the n i g h t t i m e ionosphere i n the presence o f e l e c t r i c
f i e l d s and recombination w i l l be proposed t o account
f o r the behavior p a t t e r n s .
9:30
EE
3
UHF Radio-Auroral Doppler Velocities and
Electric Fields. D.R. MOORCROFT, Univ. of Western
Ontario.— Radio-auroral Doppler velocities have been
obtained using the 398 MHz phased-array radar operated
by SRI International at Homer, Alaska. These have
been compared with simultaneous measurements of electric field made with the Chatanika incoherent scatter
radar during a very disturbed period on 27 Feb., 1976.
An earlier study at 50 MHz suggested that radio-auroral
Doppler velocities are a direct measure of E x IÎ drifts
in the ionosphere1. This finding is not confirmed by
the present study; it appears that different processes are involved in generating the scattering irregularities at these two frequencies. The Doppler velocities show a dependence on the electric field, but the
relationship is complicated and not entirely consistent with any of the instabilities proposed so far.
' w . L . Ecklund, B.B. Balsley and D.A. Carter, J.
Geophys. Res. 81, 195 (1977).
9:45
EE4
Doppler and Azimuthal V a r i a t i o n s i n HF S i g n a l s .
G.F. Lyon, Uni v." o f Western TîrTtario-- 'Observations are
made on the 7.335llHz~TSU s i g n a l propagating over the
Ottawa t o London path (530 km) in a one-hop mode. Both
the doppler frequency s h i f t and the azimuthal angle o f
a r r i v a l o f the s i g n a l are recorded.
Quasi p e r i o d i c
f l u c t u a t i o n s i n both parameters are i n t e r p r e t e d i n
terms o f T r a v e l l i n g Ionospheric Disturbances a t the
r e f l e c t i o n height.
The observations are compared w i t h
the p r e d i c t i o n s o f a simple corrugated r e f l e c t o r model.
ATMOSPHERIC THEORY AND MEASUREMENT
10:00
A Simplified Phase-Swept Interferometer
EE 5
for I onospheric Measurements. A.R. WEBSTER,
A simplified and
Univ, of Western Ontario.-updated version of the phase-swept interferometer is described.
Its utility in ionospheric measurements using radio transmissions from satellite-borne beacons is
discussed, with special reference to the making
of accurate measurements under very small
signal conditions.
10:30
EE6 Theoretical Studies of the Ultraviolet Dissociation Continua of the Oxygen Molecule M.W.P.CANN and
R.W.NICHOLLS,CRESS,York Univ. — Photodissociation of
the 0 9 molecule into the Herzberg and Schumann-Runge
continua have important aeronomical implications and
also determine the extinction properties of the terrestrial atmosphere between 1400& and 2300Â .Realistic calculations of the absorption cross-sections for these
continua are described and compared to measurements.
^Supported by NRC and AES.
10:45
EE7 Computer Simulation of the Dayside Aurora. R. LINK
J.C. McCONNELL, G.G. SHEPHERD, Centre for Research in
Experimental Space Science, York University, Toronto.
A theoretical one-dimensional computer simulation of
dayside magnetospheric cleft auroral processes has
been developed in conjunction with the rocket-borne
observations at Cape Parry, 1974. The rocket payload
provided a determination of the OI6300X and 5577A,
NI52008, and N 2 + (0,l) band emissions, the differential
electron energy spectrum, and the electron density and
temperature, while a near-simultaneous 1SIS-2 pass
furnished topside electron densities. By solving a
system of coupled continuity equations for the ionic
and metastable species, which includes the effects of
both ionospheric electric fields and neutral winds, it
may be possible to determine the high-latitude ion
convection and neutral wind velocities from the observed poleward decay of the optical emission intensities.
11:00
The Red Auroral Oval. G.G. SHEPHERD, Centre
EE8
for Research in Experimental Space Science, York
University, Toronto.Polar plots of the 6300À atomic
oxygen emission intensity in invariant coordinates are
now being obtained from the Red Line Photometer on the
ISIS-II spacecraft. These maps are combined with
direct measurements of particles,currents and plasma
densities at specific local times in order to understand the nature and distribution of the low energy
(E < 300 eV) input to the polar cap. The region of
energy input includes both the diffuse and the discrete
auroral regions, often with a sharp demarcation between the two. There is evidence that the magnetospheric morphology of this low energy component is
distinct from that of the higher energy plasma sheet
population.
43
11:15
FF9
"t
Measurements of e-ion Recombination for H 3 0 ,
H 2 0 , HOT P. MUL, P. DEFRANCE*, V.S. D'ANGELO, J.W.
McGOWAN, Univ. of Western O n t a r i o . —
Because of the
presence of water in our atmosphere its associated ions
HaO"*", H2O+, OH^ as well as their hydrates play an important part in the chemistry of the atmosphere, particularly within the D-region. Similarly, H 3 0 + is of particular importance in interstellar clouds.
Through a
series of merged electron-ion beam experiments MEIBE, we
have been able to determine the total recombination
cross sections over an energy interval 0.01 to 1 eV.
Not only are all three cross sections close to the maximum expected for molecular ions, but to our surprise
the magnitudes and shapes of the cross section curves
for H3O"1", H 2 Û + and 0 H + are remarkably similar. The near
1/E dependence of the cross section at low energies
agrees with theory and is consistant with the results of
Leu et al 1 but does not agree with findings of Heppner
et al 2 .
This work is supported by NRC and the USDOE
*M.T.Leu, M.A.Biondi and
2
R.Johnsen,Phys.Rev.A^,292,1973.
R.A.Heppner,F.L.Walls,W.T.Armstrong
Rev.A7,1000,1976.
and G.H.Dunn,Phys.
11:30
EE10
Diagnosis of Urban Hazes by Quantitative Study
of Extinction of the Spectrum of Daylight* R.W.NICHOLLS,
F.E.BUNN, W. FABIAN and D.B.CARD, CRESS, York Univ. —
A data base on the spectrum of daylight at Toronto is
being established using a scanning spectrometer,digital
memory unit and minicomputer processing. One set of
analyses of these data has been to use a comparison of
S.Horizon to Zenith daylight spectra to provide diagnostic information on the character of the urban brown
haze which sometimes occurs during the Summer over
Toronto. We have identified NO2 and monodisperse aerosol components in the haze. By computing synthetic
spectra based on Mie scattering theory we have been
able to infer column densities, particle sizes and refractive indices of the aerosol particles, and column
densities of
.
Supported by Ont. Min. Env. and NRC.
11:45
EE11
Multiple Scattering and Reflectance Measurements in Water-droplet Fogs. S.R. PAL, J.S. RYAN and
A.I. CARSWELL, York University, Toronto —
Laser beam scattering (514 nm) in laboratory generated
water droplet fogs has been studied under highly controlled conditions in the forward and backward directions. Polarization measurements of the backscattering
were made and used to separate the contributions of
single scattering, and polarized and unpolarized multiple scattering.
Studies were made for various receiver
fields of view with fog attenuations ranging from 0 to
5 m~l. The fog reflectance was measured and compared
with the theoretical calculations done for our scattering system with due consideration to the near-field
effects. These comparisions reveal that the apparent
discrepancy between the theory and experiments on cloud
reflectance described in the literature^ arises from an
underestimate of the multiple scatter contribution.
B.J. Brinkworth, Appl. Optics, 12 427, (1973).
OPTICAL PHYSICS III - LASERS
WEDNESDAY, JUNE 14, 1978
ROOM 3024
Chairman:
A. Carswell
9:00
EFl
Research at the Laboratoire de Recherche en Optique et Laser
C. DEL ISLE, UrUveAAiXé
LavaZ
The research activities of the Laboratoire de Recherche en Optique et Laser, at Laval University
in Quebec will be reviewed.
9:30
EF2
Stabilizing the Frequency of TEA-CO2 Lasers
J.L. LACHAMBRE, VREV, Nou) u)M. the
InAttfuut
de nacWoAcWo. da
VHydro-Québec,VaAmnoj>
The mode and frequency control of TEA-CO2 lasers is discussed with reference to applications requiring a high degree of monochromaticity and spectral purity. Due to the coherence processes involved in their detection system, optical radars and velocimeters
form the application category that imposes, in addition to the high peak power and repetition rate requirements, the most stringent restrictions on the transmitter frequency
stability. Among the different methods used to select a single longitudinal mode of a
TEA-CO2 laser, the injection and the hybrid-laser techniques are retained for their compatibility with high repetition rate operation of the laser source and for their applicability to active frequency stabilization.
An injection-stabilization method that uses
a single master oscillator to serve simultaneously the injection and stabilization functions in a TEA-C02 laser transmitter is described. An alternate and very p r o m i s i n g mode
selection and stabilization approach uses the hybrid configuration where a low-pressure
and a TEA gain sections are mounted in a common optical cavity; the CW laser signal emitted from such a laser is compared with a frequency reference to generate the error signal
of the stabilization system. Considering both the interpulse and the intrapulse frequency
stability, the respective performance, advantages and limits of the two stabilization systems are compared and discussed.
44
10:00
EF3
A Compact. Sealed, Single Mode TEA-C0„ Lasers
PAUL PACE, Defence Research Establishment, Valcartier
- Measurements have been made on the operation of a
the energy conversion efficiency, spectral characteristics
temporal behaviour of some UV and visible
laser dyes have been investigated. It was found that
the most efficient Cv30%) UV dye - p-terphenyl exhibits some unusual features at high levels of pumping.
small single-mode TEA CO,, laser both at high-repetition rates and at 1 pps.
Mass spectrometric gas
Visiting Scientist on the National Research CouncilUSSR Academy of Sciences Exchange Programme.
Permanent address:
Institute of Physics of the Belorussian Academy of
Sciences, Minsk, U.S.S.R.
decomposition studies on the high-repetition-rate
laser, along with a theoretical model indicate that
the addition of CO and H^ will allow sealed operation.
SLM operation of a second laser was achieved
using an 18-cm long cavity and the proper choice of
mirror radii.
Results of heterodyne beat frequer •_)•
measurements indicate a "chirp" of about 5 MHz/us
during the tail of the pulse and pulse-to-pulse stability of about i 2 MHz.
Feedback stabilization
using a digital technique to eleminate long-term
drift will also be discussed.
10:15
EF4
Tunable Harmonic Generation in the Lyman-q Region Using Pxciroer-PiiTped Dye Lasers.* T.J. MCKFFt, B.P.
STOICHTFF and S.C. UALLACF, Dept. Physics, Univ. of Toronto . -Ultraviolet dye lasers pimped by a KrF excimer laser 1 have been used to extend the ranae (2000-1300&) of
tunable coherent VUV radiation, generated by four wave
sun-mixing in magnesium vapour 2 , to the spectral region
around Lyman-a. A photon flux of 10 8 -10 9 photons per pulse vas achieved in the region 1200-1300R. Possible applications of this narrow linewidth radiation include F-atan
detection by resonance fluorescence and in situ determination of the velocity distribution of hot I—atoms. Sere
properties of excimer-pirtped dye lasers will also be
discussed.
*
Supported ty NRC PRAI grant
+
Present address: Ltmonics Research Ltd., 105 Schneider
Road, Kanata, Cntario.
1
T. HcKee, B.P. Stoicheff and S.C. Wallace, Appl.Phys.
Lett.30, 378 (1977).
2
S.C. Wallace and G. Zdasiuk, Appl.Phys.Lett.29, 449 (19
—
76).
10:30
EF5
Multi-atmosphere Self-sustained Discharge Rare
Gas Halide Lasers. W.J. SARJEANT, R.S. TAYLOR,
A.J. ALCOCK and K.E. LEOPOLD, N.R.C.,—The evolution
and operating characteristics of several varients of
multi-atmosphere uv preionized rare gas halide lasers
are described with particular emphasis on the discharge
properties, especially uniformity, and their impact
upon the prospects for obtaining high energy pulses of
near diffraction limited uv radiation.
10:45
EF6
Investigation of Laser Dyes Pumped by High Intensity KrF* Laser Radiation. V.I. TOMIN7 A.J. ALCOCK,
W.J. SARJEANT and K.E. LEOPOLD, N . R . C . — The development of rare gas halide lasers has provided powerful
new sources of UV radiation and extended to significantly shorter wavelengths the pump radiation available
for pumping dye lasers. Using a multi-atmosphere KrF*
laser with a peak output in excess of 30 MW at 248 nm
11:00
EF7
" H i g h - p o w e r t r a n s v e r s e m o d e - l o c k i n g •ty s h o r t
pulse injection
n a TEA-CO? l a s e r " .
M. PI CUE a n d
P . A . BELANŒR, U n i v e r s i t é L a v a l . - - S h o r t p u l s e
i n j e c t i o n ' i n a l o w - l o s s TEA-CO? c a v i t y made o f two
cop]ier m i r r o r s h a s r e s u l t e d in t h e p e r i o d i c f o c u s s i n g
of the i n t e r n a l p u l s e .
T h i s c f f e c t was a t t r i b u t e d t o
t h e s i m u l t a n e o u s l o c k i n g o f l o n g i t u d i n a l and t r a n s v e r s e modes.
The f o c u s s i n g was c o m p l e t e l y s u p p r e s s e d
by l i m i t i n g t h e g a i n a r e a t o t h e f u n d a m e n t a l t r a n s v e r s e m o d e , o r b y u s i n g an u n s t a b l e r e s o n a t o r .
By
measuring the p e r i o d i c i t y of the f o c u s s i n g , the
l o c k i n g a c t i o n o f t r a n s v e r s e modes o f e i t h e r r e c t a n g u l a r o r c i r c u l a r symmetry c o u l d be e v i d e n c e d .
A
t h e o r e t i c a l a n a l y s i s w i l l a l s o be p r e s e n t e d .
'P.A. Bélanger
720 ( 1 9 7 0 )
and
B o i v i n , Can. J .
Phvs.
54,
11:15
EF8
Short 10 tim Pulses Using Semiconductor Reflection Switching. P.B. CORKUM and A.J. ALCOCK, N.R.C., —
Picosecond pulses of visible radiation (A
0.6 nm}
have been used to gate short infrared (10 ^m) pulses
from the output of a low pressure COa laser. Computer
simulations suggest that, neglecting recombination and
hot carrier effects, 10 pm pulses of *v25 ps duration
can be obtained from a single germanium switch and even
shorter pulses with series switching arrangements.
Correlation measurements of the 10 nm pulse duration
will be presented.
11:30
EF9
HIGH RESOLUTION SPECTROSCOPY WITH A TEA-CO,
LASER.* J.R. IZATT and P. MATHIEU, LROL, Université
Laval. —
When one of the end mirrors of a TEA-COj
laser is replaced by a Michelson interferometer, the
laser output can be made to coincide with a Doppler
broadened absorption line by placing a sample of the
absorbing gas in one arm of the interferometer and
adjusting the latter for destructive interference.1
The TEA laser can be tuned by about 1.8GHz on either
side of the central frequencies of the CO2 rotational
lines on which it normally oscillates by this technique. The frequency of the laser output, and hence of
the absorption line, can be determined with a resolution of the order of 100 MHz by using a tiltable FabryPerot étalon to measure its displacement from the
corresponding line produced by a low pressure CO2
laser. This procedure has been used to study the
9.3 ym band of CH3OH.
*
Supported in part by the National Research Council.
1
P. Mathieu and J.R. Izatt, Optics Commun,
(accepted for publication).
45
11:45
EF10
Response of the Liquid-Filled Optoacoustic Cell
to a Laser Pulse. Theory and Experiment. J.A. BURT and
D. EFTHIMIADES, York U n i v . — Although most optoacoustic
cells or spectrophones are entirely gas-filled or
contain a buffer gas along with a liquid sample drop
completely liquid-filled spectrophones are also important. They may be used for example in continuous, onstream monitoring of liquid pollutants or as air-to-sea
communication hydrophones. The spectrophone irradiated
by a pulsed dye laser is treated as a two dimensional
problem due to the assumption that the contained fluid
has a low absorption coefficient. A closed-form, analytic solution is presented for the pressure produced
at the spectrophone cylinder inner wall due to light
absorbed on the cylinder axis. Numerical solution of
the output voltage from the piezoceramic cylinder is
compared with experiment for various fluids.
12:00
EF11
Two-Photon Laser Spectroscopy of Indium.
M.Y. MIRZA and W.W. DULEY, Department of Physics, York
University, Toronto, O n t . — A s part of a study of the
spectra of the group IIIB elements^ ' using laser spectroscopy coupled with ion detections, we have examined
the spectrum of indium. Two-photon transitions from
the 5^P° 1 /2 a n d 5 2 p °3/2 states of In have been observed
to high lying 2 P ° and
states. Extended series
corresponding to P°
nP° and P° -»• nF° transitions are
seen to n = 23 and n = 31 respectively. A hybrid resonance^) through intermediate states of In2 gives
rise to a series 6s 2 S -»• np 2 P° which can be followed to
n = 42. Resonant enhancement of the 5 2 P°3/2 -*• np 2 P°
series occurs because of an intermediate 2 S state. This
produces a singularity in the cross-section for this
transition. Possible two-photon transitions to autoionizing states of In are also seen. Details of the
spectrum of In obtained will be presented.
1. Mirza, M.Y. and Duley, W.W. , J. Opt. Soc. Am. 6^7,
1417 (1977) and Opt. Comm. (in press).
2. Collins, C.B. et al., Phys. Rev. A10, 813 (1974)
CONFINEMENT MAGNETIQUE, ONDES, INSTABILITES
WEDNESDAY, JUNE 14, 1978
ROOM 3026
Chairman:
M.C. Richardson
9:00
EG1
Plasma Confinement in the KEMP II Electromagnetic Trap. J.M. LARSEN, B.L. STANSFIELD, B. BERGEVIN,
J.P. MATTE, B.C. GREGORY, INRS-Energie, Université du
Québec. — In the KEMP II device we create a plasma in
an open cusp-configuration magnetic field, using electrodes to prevent loss parallel to the magnetic field
lines. We have been able to produce plasmas with densities up to ~ 10^2cm~-^, electron temperatures of
about 30 ev and confinement times in the range 100200 usee. The plasma density seems to be limited by
the input beam power of the electron gun used to create
the plasma. The confinement of the plasma electrons
is dominated by cross-field diffusion to the grounded
electrodes which define the plasma boundary. The ions
are lost to the high voltage electrodes, but their
confinement mechanism is uncertain at this time.
9:30
£Q3
Beta Limit Imposed by Ballooning Instability
in Tokamaks. * AKIRA HIROSE, Univ. of Sask.—The
ballooning mode in a large aspect ratio tokamak is
re-examined analytically.
In the past, the magnetic
field perturbation (BJJ) along the unperturbed magnetic
field and the plasma temperature perturbation have been
neglected.
It is shown that B || has to be^taken irto
account if the plasma incompressibility (V • v = 0;- is
imposed and also the temperature perturbation shou-d
inevitably appear whenever the plasma has a temperrture gradient. The new differential equation for the
ballooning mode is
r*L.
LÏÏÔ2 +^
£ M l i
Ho 2
( (1
11
V
- -f COS0)
]<f> = o,
(1)
where 6 is the minor azimuthal angle, 8 is the (toroidal) beta factor, q is the safety factor, R/a is the
aspect ratio and (p is any one of the perturbed quantities. Equation (1) predicts B < /2 a/qR (or B p ,
polidal beta, </2 qR/a) for stability, which is much
less stringent than that previously imposed. 1
^Sponsored by NRC.
1
H.P. Furth, et al., IAEA Culham conference, ( I A E A ,
Vienna, 1966) p. 103, vol. I.
9:15
EG 2
Electrostatic Confinement in a Double Cusp.
P. COUTURE, B.L. STANSFIELD, INRS-Energie, Univ. du
Québec. — To study is more detail the physical
mechanisms which are important for electrostatic confinement of plasmas, we have constructed a Double
Cusp device. The plasma is created between the two
cusps via an Electron Cyclotron Resonance source, the
plasma extending axially to fill the trap. The plasma
density is about 2 x 10-*-(-)cm"3, with an electron temperature of about 10 ev. Profiles of the electron and
ion densities and plasma potential have shown a clear
confinement of the particles parallel to the magnetic
field lines. The electrons are lost via cross-field
diffusion, while the ions are lost along the field
lines to the high voltage electrodes. With application of the confining voltages, the plasma potential
becomes negative (~ 20 Volts) .
9:45
EG4
Experimental Study of Microwave Radiation
Emitted by a Turbulently Heated Toroidal Discharge."
H.W.H. VAN ANDELj Département de Physique. Université
de Montréal. - Microwave radiation emitted from the
toroidal discharge T0RTUR during the application of
a large amplitude turbulent heating current was
monitored with a ten-channel microwave spectrometer
operating in the 10 GHz - 40 GHz range. The measured
spectra are in qualitative agreement with a model
that assumes the radiation to be due to beam-plasma
instabilities associated with a bump-in-tail electron
distribution function. Details of the measurements
and their theoretical interpretation will be discussed.
* This work was performed while the author was on
sabbatical leave at the FOM Institute for Plasma
Physics in Jutphaas, The Netherlands.
46
10:00
EG5
Damping of a Plasma Wave with Detrapplng of the
Electrons.* G. P0C0BELLI, Univ. of Saskatchewan.—
Theories of the damping of a plasma wave of large
amplitude have so far assumed, inconsistently, conservation of the number of particles trapped in the wave.
The mathematical difficulties against removing such an
assumption are solved here by constructing a single
analytical expression for the motion of an electron
interacting with a slowly damping sinusoidal wave,
which describes both untrapped and trapped particle
states. A transformation law for the Fourier coefficients of the motion is therefore obtained, and it is
this transformation which describes the transition
between such states in the damping integral. The
theory appears to be sufficiently simple and general
as to be extended to a number of problems, unsolved so
far, involving particle trapping or detrapplng by a
plasma wave, the main assumption being that the amplitude of the wave change slowly over an electron bounce
time T - (eE o k/m) l/2 .
*
Supported by the National Research Council
10:30
EG6
Parametric Study of Dissipative Drift Modes
and their Stabilization using Oscillating Azimuthal
Magnetic Fields': C.BOUCHER, S.Q. MAH, H.W.H VAN ANDEL
and J.TEICHMANN, Département de Physique. Université
de Montréal. - Experimental investigation of dynamic
stabilization of dissipative ^rift modes in a weakly
ionized plasma was continued . Variation of the main
confining magnetic field strength in the plasma
column allowed the creation and identification of a
number of discrete modes, which are predicted by
theory. The identification of the modes involved
detailed measurement of the azimuthal k-vectors, and
the corresponding frequency spectra. The dynamic
stabilization of these modes was studied, and the
experimental results compared with theory.
1
H.W.H. Van Andel, J.Teichmann, and S.Q.Mah, Physics
of Fluids 22, 442 (1977)
*
Research supported by the National Research Council
of Canada, and le Ministère de l'Education du
Québec.
10:45
EG7
Experimental Study of Stark Broadening of Nitrogen II and III Line Profiles.
E. KALLNE, L. A.
1
JONES " and A. J. BARNARD, Univ. of British Columbia.—
We have used a 60 kV-60kJ single turn coil theta pinch
to produce a dense plasma for studying Stark broadening of nitrogen ion line profiles. The discharge tube
was filled with 3 torr He-N2 mixture. The electron
density was measured from the Stark broadening of Hell
4686 A line as well as from shadowgrams using a 2J
20ns ruby laser and was found to be 1-2.10 18 cm" 3 . The
electron temperature was estimated from relative intensities of emission lines from Nil and NIII. We
have studied the 3s-3p, 3p-3d and 3d-4f multiplets for
Nil and NIII and will compare the measurements with
theoretical predictions using available Stark broadening parameters for these ions.
Los Alamos Scientific Laboratory, Los Alamos, New
Mexico.
11:00
Etude de l'instabilité des bandes latérales par
simulation. Magdi M. Shoucri, direction Sciences de
base, Institut de recherche de 1'Hydro-Québec, Varennes,
Québec, Canada. JOL 2P0 — L'origine physique de la
croissance des bandes latérales (sidebands) d'une onde
plasma de large amplitude est étudiée numériquement.
L'équation de Vlasov est intégrée numériquement dans
l'espace des phases. On montre que pendant l'évolution
nonlinéaire d'une onde de large amplitude dans un plasma unidimensionnel, la fonction de distribution du plasma est déformée de façon a avoir une région ayant une
pente positive et la vitesse de phase de l'onde coïncide approximativement avec le minimum de la fonction
de distribution (le point neutre). La formation de
cette région de pente positive est accompagnée par la
croissance des bandes latérales à l'onde fondamentale.
La vitesse de phase de la bande latérale inférieure est
à l'intérieur de la région où la fonction de distribution possède une pente positive. La croissance des
bandes latérales se poursuit jusqu'à un niveau tel que
la région de pente positive de la fonction de distribution est modifiée en une région ayant un plateau plat.
Nos résultats indiquent la possibilité d'un couplage
nonlinéaire entre la première harmonique de l'onde fondamentale et les deux bandes latérales.
11:15
EG9
Interaction Effects of High Energy Plasma
Particle Beams with Metallic Surfaces. M. DEMBINSKI,
P.K. JOHN, A.G. P0N0MARENK0, Univ. of Western Ontario.
— With the development of test fusion reactors there
is increasing interest in plasma-wall interactions,
its effects en plasma parameters and on plasma stability. In this report we describe preliminary results
of a model experiment to study the physical processes
resulting from the bombardment of high energy charge
particles on metallic surfaces. Particle beams of
energy between 5 keV and 20 keV are extracted from a
moving low temperature plasma stream and resulting
currents of up to 100 A are incident on selected
metallic surfaces. Particle and plasma emissions
from the surface are studied under various initial
conditions.
47
WEDNESDAY, JUNE 1 4 ,
ROOM 3 0 2 8
Chairman:
LAYERS, SURFACES AND BRILLOUIN SCATTERING
1978
w . B . Muir
9:00
E
H1
NMR of Hq and Dq Adsorbed on Graphite. P.R.
KUBIK and W.N. HARDY, University of B.C.-We have used
the splitting of the NMR line to probe the orientational state of ortho-H2 and para-D2 molecules adsorbed
on Grafoil, a form of exfoliated graphite.
For
,
this system is known to correspond to a two-dimensional
1
triangular array of quadrupoles when the coverage is
less than 65% of a full monolayer.
The NMR splitting
is proportional to the order parameter <3J£ 2 -2>.
From
its temperature dependence in the range 1.06 to 4.2 K,
the crystal field splitting of the J = 1 state due to
the substrate and neighbouring molecules has been determined to be .55 K for 0-H2 and 2.5 K for P-D2.
For
P-D2 at low temperatures there is clear evidence of a
temperature dependent molecular field arising from
quadrupolar interactions.
However as yet no transition
to any of the expected orientationally ordered states 2
has been observed.
9:45
E
**4
Nonlinear Surface Plasmon Interactions.
M. FUKUI, G.I. STEGEMAN, Univ. of T o r o n t o — N o n l i n e a r
surface plasmon interactions at the surface of a free
electron gas occur due to the nonlinear electronic
response of the metal.
This interaction has been
analysed on the semi-infinite metal for two geometries, i.e., harmonic generation and the mixing of
oppositely travelling plasmons.
In the first case,
the growing field was evaluated and the position and
magnitude of the maximum second harmonic power were
calculated.
For the oppositely propagating case,
coupling can occur to bulk plasmons, surface plasmons
and radiation fields.
Nielsen, J.P. McTague, and W. Ellenson, to be
published.
2
A . J . Berlinsky and A.B. Harris, to be published.
9:15
EH2
Orientational Phases of Hydrogen Molecules on a
Triangular Lattice. A.J. BERLINSKY, Univ. of British
Columbia and A.B. HARRIS, Univ. of Pennsylvania.-A mean
field theory for the ordering of hydrogen molecules on
a triangular net is derived in terms of the quadrupole
coupling constant T, the crystal field V c , and the
temperature T. The phase diagram consists of six
regions, separated by first and second order transitions.
For almost all values of V c / r for which ordering occurs, the disordered to ordered phase transition
is continuous.
At T = 0 K , all phases have energy gaps
except for a ferrorotational phase which behaves like
an XY model.
9:30
EH3
Theory of Surface Spin Waves in a Tight-Binding
Model of a Transition Metal.
G. GUMBS, Division of
Chemistry, NRCL, Ottawa and A. GRIFFIN*, University of
T o r o n t o . — W h e n a ferromagnet has a planar surface, the
transverse spin-spin correlation function x + _ ( r » r ' » w )
may have a pole corresponding to a surface spin wave
mode, in addition to the usual bulk spin wave modes
characteristic of an infinite ferromagnet.
We have
calculated 1 x +
f° r a simple model of a itinerantelectron ferromagnet based on a single tight-binding
band for the d-electrons in a simple cubic lattice
with a surface.
We use a Hubbard Hamiltonian which includes hopping between nn sites and on-site exchange
interactions.
If the surface-induced changes in the
static spin polarization near the boundary are ignored,
a closed form solution of the self-consistent-field integral equation for x +
I s possible.
The resulting expression for x + _ exhibits a surface spin wave branch
which lies above the bulk spin continuum, rather than
below as in the case of Heisenberg models.
In Nickel,
this mode is localized within the first few surface
layers, has energy - 1 0 - 1 e V , a n d should be observable in
a spin-polarized ILEED experiment.
*Work supported by NRCC.
1
G . Gumbs, Ph.D. Thesis, University of Toronto, 1978.
10:00
EH5
GaAs Anodization in M-KOH.* J- D. CANADAY and
C. W. FISCHER, Univ. of Guelph —
Calvanostatic
anodization of n-type GaAs in 0.02 to 1.0 N methanolic
KOH is shown to be a faradic process.
Voltage time
graphs, at various current densities and electrolyte
concentrations, are used to construct Tafel plots.
These graphs show that at constant current density the
oxide field is inversely proportional to the electrolyte concentrations.
The slopes of the individual
Tafel lines are used to determine the type of ion
drifting through the oxide during anodization.
The
anodization efficiencies and the anodization constants for several electrolyte concentrations will
also be discussed.
^Supported by the National Research
Council
10:15
EH6
Correlation of Some Properties of Epitaxial Layers of GaAs^_ v P with Certain Conditions of Fabrication*. X A. LOOKICHEV, Institute for Materials Research, McMaster University. — A study was made of the process that
occurs after vapor-phase epitaxial growth of
GaAsn X P . It was found that the conditions
for termination of the process (characterization of residual HC£, composition of the vapor
phase and rate of cooling) have a strong influence on the properties of the sub-surface
epitaxial layer. Surface quality and the
efficiency of cathodoluminescence depend upon
the forms of vacancy states, thermal etching
(decomposition) or nonstoichiometric growth of
subsurface layer. Means were found to improve
surface quality and efficiency of luminescence
properties of epitaxial structures. The criteria developed for GaAs^_ x P x epitaxial layers
are important for the use of this material for
devices such as LEDs.
*Experimental part of this work was done in
Moscow Institute of Electronics, Moscow, USSR.
48
10:45
EH7
Interfacial and Dielectric Properties of GaAs
MPS Structures.* C.W. FISCHER and J.D. CANADAY, Univ.
of Guelph — The interfacial and dielectric properties
of anodic oxides grown on n-type GaAs are shown to depend strongly upon the electrolyte concentration and anodic current density. The static current-voltage and
the small signal AC admittance-voltage characteristics
at frequencies between DC and w-lO's" 1 are measured as
functions of oxide growth conditions.
Capacitance-voltage graphs show that as the electrolyte concentration
is reduced, the interfacial charge storage is also reduced. The oxide charge and the interface state density
are measured by comparing the experimental capacitance
voltage graphs with ideal theoretical graphs. Oxide dielectric strength measurements are shown to be relatively insensitive to oxide thickness, however the dielectric strength is dependent upon the electrolyte concentration. Static current voltage data has been measured
in the range of 10~ 12 to 10~s A and this data is consistent with a Frenkel Poole emission model.
^Supported by National Research Council.
11:00
Ejjg Adsorption de molécules simples et des hydrocarbures légers sur les métaux. J.D. CARETTE et A. ADNOT.
Centre de recherches sur les atomes et les molécules,
Univ. Laval. Un spectromètre électronique à très haute
résolution (AE/E = 0.012) est utilisé pour étudier 1'adsorption des gaz à la surface des métaux. Ces dernières
constituent le substrat sur lequel les particules qui
s'y fixent représentent l'adsorbat, dont les éléments
sont appelés adatomes ou admolécules selon le cas. Les
électrons émis par la source du spectromètre excitent
les modes vibrationnels des composants de l'adsorbat.
La mesure du spectre d'énergie des électrons réfléchis
révèle quels sont les modes excités. En les comparant
avec ceux obtenus en phase gazeuse on peut tirer des
conclusions intéressantes quant à la nature et à l'état
des espèces adsorbées ainsi qu'aux modifications subies
dans le passage de la phase gazeuse à la phase condensée. Les molécules dont on présente les résultats de
l'étude sont NH 3 , CH 3 0H, CjH OH et CH -OO-CH . On observe que les énergies des états de vibration détectés
sont en bon accord avec celles en phase gazeuse, sauf
pour l'absence des vibrations des liaisons 0-H et C =0.
Ce qui indique leur rupture et la fixation du fragment
lourd à la surface par 1'oxygène.*J. Phys. E: Sci. Instrum. 8, 109 (1975); phys. Rev. Lett. 38, 1084 (1977).
11:15
EH9
Brillouin Scattering From Thermal Surface Phonons
N.L. ROWELL and G.I. STEGEMAN, Univ. of Toronto—Light
scattered at 90° in the plane of a dielectric thin film
deposited on a substrate (i.e., an optical waveguide) has
been detected and analysed using a multipass Fabry-Perot
interferometer, photon counting and a multichannel memory. A peak in the spectrum corresponding to thermal
surface waves has been observed. From the measured
frequency shift and linewidth it has been possible to
measure the velocity and attenuation of surface waves of
frequency approximately 11 Ghz. Phonon lifetimes of the
order of 3 x 10~® seconds were found.
11:30
EH10
Brillouin Scattering from Single Mode Optical
Fibers. P.J. THOMAS, N.L. ROWELL, H.M. VANDRIEL,
G.I. STEGEMAN, Univ. of Toronto—The linewidth of Brillouin scattered light trapped in an optical fiber was
studied as the intensity of pump illumination approached
the threshold for backward stimulated emission. Light
at 514.5 nm from a single-frequency argon-ion laser was
coupled into the TMQO mode of a single-mode silica-core
fiber, and the Brillouin scattered radiation was analysed by a triple-pass Fabry-Perot interferometer followed by photon-counting electronics and a multichannel
analyser. A linewidth of 300 MHz was measured for the
longitudinal Brillouin components, which is much larger
than the linewidth observed in bulk samples of fused
silica. These results have been interpreted by including fiber boundary effects.
11:45
EH11
Damage Thresholds of Thin Film Waveguides.
R. NORMANDIN, V. SO, G.A. TEH, G.I. Stegeman, Univ. of
Toronto—Vhe suitability of integrated optics for investigating nonlinear optical wave phenomena can be
limited by the damage threshold of the thin film. The
power handling capability of optical waveguides was
investigated using a harmonically doubled Nd:YAG laser
operating at 0.53 Pm. R.F. sputtering was used to
deposit various optical glasses onto fused silica substrates and the resulting waveguides had losses typically of the order of a few db/cm. Using glass coupling
prisms, power densities in excess of 10 Mw/cm 2 were
obtained in the films which indicates that the measured
waveguide losses are due to scattering rather than
absorption. Results will be given for a range of
glasses.
49
WEDNESDAY, JUNE
ROOM 2 0 5 0
Chairman:
P.A.
13:30
FA1
14:15
FA 2
15:00
FA 3
14,
PLENARY SESSION:
1978
THE UPPER ATMOSPHERE
Forsyth
On Getting High
C.O. HINES, University
of
Toronto
Studying the Upper Atmosphere with Radio Waves
D.R. MOORCROFT, The University
of Western
Ontario
Optical Studies of the Upper Atmosphere
J.F. NOXON, U.S. Department of Commerce
A few selected examples will be used to show how relatively simple optical schemes can be employed
to provide important information on the composition, dynamics, and energv balance of the atmosphere
above 10 km.
15:45
Break
WEDNESDAY, JUNE 14, 1978
ROOM 2050
Chairman: H.E. Johns
Annual General Meeting of the Canadian Association of Physicists
16:00
FBI
16:30
Presidential Address: Physicists in Medicine
H.E. JOHNS, President
of CAP, Ontario Cancer
Institute
Annual General Meeting
WEDNESDAY EVENING
Reception and Banquet
18:45
Reception:
Lounge, Saugeen-Maitland Hall, Hosted by the University of Western Ontario
19:30
Banquet
Presentation of CAP Awards
50
JOINT CAP/AAPT EDUCATION SYMPOSIUM
THURSDAY, JUNE 15, 1978
Chairman: P.A. Whlppey
\
ROOM 2036
9:00
GA1
Physical Science in the Intermediate Years
R.H. STINSON, OntasUo I r u t i t u t e (,ol Stiidiu
ijn. Education,
London
Ontario has passed through a 17-year period in which the physical science curriculum (7-10) has
moved through certain phases. First, a structured approach was used with concepts organised
mainly around environmental phenomena, eg. air, water, light, etc. Then a more loosely organised
guideline allowed schools to develop units in 7-8 and courses in 9-10. Now in 1978, the province
is moving back to a more prescribed curriculum using units of study, with some of these mandatory
across the four years.
9:45
GA2
Physics in Community Colleges
H. JANITIS, Fanihawe College o& Applied
Aiti
and
Technology
The Coiununity College was established in Ontario about 10 years ago to fill the educational
needs of individuals who have a practical applied orientation rather than an academic one.
Physics is required to provide the basic theoretical framework appropriate to the students
area of specialisation. The choice of curriculum and manner of presentation is constrained
by the students background (generally varied), the College's structure and the student's
employment aspirations upon graduation.
10:30
Break
ROOM 2050
11:00
GA3
The Flying Circus of Physics
J . D . WALKER, Cleveland State
UniveAilty
This talk demonstrates how puzzling aspects of the real world, violent demonstrations, and counterintuitive examples can be used to make classroom physics lively and memorable. The topics are
extensions of those in my book and in my articles for Scientific American and will cover the following:
the dunking bird; the twirl-a-tune toy; the rate of freezing hot and cold water; the metallic colors
of butterflies; multiple-order rainbows; karate brick breaking; dipping my fingers into molten lead;
walking on live coals; and lying on a bed of nails.
THURSDAY, JUNE 15, 1978
FACULTY CLUB, SOMERVILLE HOUSE
ROOM 213
13:00
CAP COUNCIL
Chairman:
R.R. Haering
51
AUTHOR INDEX/INDEX DES AUTEURS
Aashamar, K., DF5
Abe, K., AA3
Abegg, R . , BD2
Abou-Zeid, O., BD2
Adnot, A., EH8
Ahlborn, B., BE3,9,10
Albert!, F., AE6
Albrecht, G., CF2.3
Alcock, A.J., EF5,6,8
Al-Ghazi, M.S.A.L., DF7
Altounlan, Z., AG4,5
Amsler, C,, CC5
Ansaldo, E.J., BD3
Armstrong, B., BE3
Armstrong, R . L . , AE10; EA2
Auld, E.G., AC4; DF1
Axen, D.A., CC5
Aziz, R.A., CH2
Bachynski, M.P., EB1
Bahurtnuz, A., AGIO
Bailey, J., DF1
Baldis, H.A., AF5.10; CF5
Bancroft, G.M., CA1
Barnard, A.J., EG7
Barton, R.J., AG3
Battista, J.J., ED6
Beaudry, G., CF1
Beer, G.A., CC3,4; DF1
Béique, R., AD1
Belanger, P.A., EF7
Bergersen, B., BG6; DG7
Bergevin, B., EG1
Bergstrom, J.C., BD3
Berlinsky, A.J., AA4; EH2
Birchall, J., CD2; DF7
Bock, E., BF9
Boerner, W-M., CE9
Boese, H., BC4
Borwein, J.A., DE4
Boucher, C., EG6
Brand, J.C.D., AE7,9
Brodeur, P., CD9
Bronskill, M.J., ED6
Brown, H.M., DE6
Brown, R.J.C., BF4
Brueckner, K.A., DB2
Bryman, D.A., CC3
Buckley, R., DE9
Budde, W., AB4
Bugg, D.V., CC5
Buja-Bijunas, L., CD10
Bunn, F.E., EE10
Burnett, N.H., AF5,7; CF5
Burt, J.A,, EF10
Caille, A., BF6
Cain, D., CH5
Cameron, J.A., BD8,10; BF7
Campbell, C.C.M., BF7
Campbell, J.L., DG1,5
Canaday, J.D., EH5,7
Cann, M.W.P., EE6
Carbotte, J.P., AG11
Card, D.B., EE10
Carette, J.D. , EH8
Carley, J.S., CH2
Carlone, C., BG11
Carpenter, G.J.C., DG6
Carswell, A.I., EE1
Chandralah, G., AE4
Chang, J-S., BE4.5; DE10
Chapman, G., BG9
Chapman, R., BD7; CD3
Cheeke, D., BF3
Chen, C-S., DE10
Cheng, C.W., BD9
Cheung, H., CD5
Chiu, K.C.R., DF10
Clegg, T.B., AC1
Clough, A., CC5
Cobbold, R.S.C., ED3
Code, R.F. CH10
Cochrane, R.W., CG6
Collins, M.F., BF5
Corey, J., DG8
Corkum, P.B., AF10; CF5; EF8
Cormack, D.V., BC4
Corriveau, F., BD1
Couture, P., EG2
Cowan, M., DE8
Craddock, M.K., DC2
Crawford, J.E., CD6
Cross, K.J., AE7,8
Cross, W.G., BC9
Crozier, D., CA2
Curzon, F.L., BE7
Dagg, I.R., AE2
D'Angelo, V.S., DF9,11,12; EE9
Dasgupta, S.S., BD4
Datars, W.R., AG4,5; BG2; DAI
Datta, S., BD2
Davidson, R.C., DB4
Davies, K., CB5
Dawson, D., AD3
Defrance, P., DF9,12; EE9
Delisle, C., EF1
Dembinski, M., EG9
Desai, R., BA3
Dimoff, K., BE8
Din, G.U., BD5
Dixit, M.S., CC3,4
Dobrowolski, G., AB1
Doezema, R.E., BG2
Dolling, G., EA3
Dong, R.Y., BF9
Doschek, G., AF8
Douglas, A.E., AE6
Douglas, R.J., BC8; DG4
Dreher, B., DF1
Druirnn, H. , DF1
Dubois, R., CC5
Duley, W.W., EF11
Durell, J.L. , CD3
D u w u r y , C., AGI
Dvorak, P., BC2
Eastwood, H.K., CE2
Ebrahim, N.A., AF8
Edgington, J.A., CC5
Efthimiades, D., EF10
Egelstaff, P.A., CH4,6
Eldrup, M., DG4
Enright, G.D., AF3,4,5,6,7,8
Ettinger, H., BF3
Evans, B., BE4
Fabian, W., EE10
Falk, W.R., BD2
Fawcett, E., AG9
Fearing, H.W., BB2
Fedosejevs, R., AF4
Feldman, U., AF8
Fenster, A., ED5
Fischer, C.W., EH5,7
Fletcher, R., AG2
Flynn, E.R., AC3
Fong, K., BE9
Fortin, E., BG8
Foster, F.S., ED2,3
Fowler, T.K., DB3
Froelich, H.R., DF9
Fuchs, V., CF1
Fukui, M., EH4
Gallant, M.I., BG5
Garcia, B.J., ED3
Garside, B.K., BG9; CE5
Gastaldi, U., DF1
Geiger, K.W., BC6
Gettel, L.E., BE7
Ghaem-Maghami, V. , BA5
Ghandeharian, H., CE9
Gibson, D., CC5
Gibson, R., CC5
Glyde, H.R., AG12
Godard, R., BE11
Goldstein, A., EDI
Goodchild, R.G., BG10
Gough, T.E., AE5
Gratton, M.F., BG10
Gregory, B.C., EG1
Grek, B., AF1,9
Griffin, A., EH3
Gumbs, G., EH3
Haering, R.R., AA1
Hardy, W.N., EH1
Harris, A.B., EH2
Hartmann, G., CB1
Hasinoff, M.D., BD1; EC2
Hede, B., CG3
Hedgcock, F.T., CG6
Henkelman, R.M., DC3
Heyding, R.D., BF4
Higinbotham, J., CH10
Hilko, B., CF2.3
Hill, K.O., CEI
Hines, C.O., FA1
Hirose, A., EG3
Hobson, R.M., BE4,5
Holloway, A.F., BC3,4
Holroyd, F.W., AG9
Holt, R.A., DF3
Hota, N.K., BG11
Hoy, A.R., AE7,8
Huang, H., CD5
Hubert, J., BE2
Hubert, M., BA5
Hughes, T.J., EE1
Hunt, J.W., ED2
Hyde, W.T., AG6,7
Hyland, M., CD3
Ikossi, P.G., BD8
Xng, H., BC9
Ivey, R.C. , EB2
Izatt, J.R., EF9
Jaanimagi, P., AF6
Jackman, J.A., DG1,5
Janitis, H., GA2
Jassby, D., DB1
Jean, B., BE8
Jennings, B.K., CD8
John, P.K., EG9
John, S., DE3
Johns, H.E., ED4; FBI
Johnson, D.C., CEI
Johnston, T.W., AF1,2
Jones, L.A., EG7
Joshi, Y.N., DF4
Juravel, L.Y., BG1,10
52
Kallne, E., CE10; EG7
Kane, G.L., DDI
Kapron, F.P., AA3
Kastner, B.J., CG6
Kawasaki, B.S., CEI
Keeler, R., CC5
Keyser, J., DF9.12
Kiefte, H., BA2
Kim, S.K., CC3
King, J.D., BD9
Kitching, J.E., CD4
Klein, M.L., DA3
Klempt, E., DF1
Kogan, A., CD6
Kos, J.F., AG3
Krell, M., CC3
Kroon, J., DE8
Krouse, H.R., DE2,5,6
Kubik, P.R., EH1
Kuehn, L., DE7,8,9
Kwan, J., BE10
Kwan, S.P., BD2
Lachambre, J.L., EF2
Laframboise, J.G. , B E H ; DE10
Laishley, E., DE2
Lakhani, A.A., BF3; BG3
Lam, G.K.Y., DC3
Lamarche, G., BFll
Landsberger, S., BD11; CD1,11
Lapierre, J., CE8
Larabee, A., CD10
Larsen, J.M., EG1
Latta, B.M., BD6; CG5
Laughton, D.G., DD3
Lecomte, R., BD11; CD1,11
Lee, D.M., BC3
Lee, H.J., BG1
Lee, J.K.P., CD5
Lees, R.M., AE11
Lemaire, C., AE10
Leo, W., CD4
Leopold, K.E., EF5.6
Lepine, Y., BF6
Leslie, J.R., BD7
Levinson, A.A., DE5
Lewis, J., BF9
Lewis, L.J., CH7
Liese, W., BE3
Lightstone, A.W., CE2
Lim, T.K., CE5
Lindau, I., CA4
Link, R., EE7
Lit, J.W.Y., CE4,7
Liu, C.F., AG6,7
Liu, W.-K., BA4
Loly, P.D., AGIO; DH1
Lookichev, A., EH6
Ludgate, G.A. , CC5
Luke, T.M., DF5
Lupton, L., DG4
Lyon, G.F., EE4
MacDonald, J.A., CC3,4
MacDougall, J.W., EE2
MacHattie, L., DE7
MacPhail, M., CD3
Mah, S.Q., EG6
Mai, H.H., BE8
Mak, D.K., AG8
Mark, S.K., CD9
Martel, J.G., DG3
Martin, F., AFl
Marton, J.P., CE5
Mason, G.R., CC3.4
Mathieu, P., EF9
Matte, J.P., EG1
May, A.D., BA5
McConnell, J.C., EE7
McConville, G.T., CH2
McCourt, F.R., BA4; CH11
McCready, R.G.L., DE2
McGowan, J.Wm., CA3; DE3,4
DF9,10,11,12; DG9.10; EE9
McKee, B.T.A., DG6
McKee, J.S.C., CD2; DF7
McKee, T.J., EF4
McKellar, A.R.W., AE3
McLatchie, W., BD7
McMullen, T., DG7
McNeil, K.G., ED3
Measday, D.F., BD1
Medeiros, J.A., DE3,4
Merrill, N.H., CD3
Metford, P., BD10
Meyer, J., CF2,3
Michaud, G., BB3
Michaud, M., BG11
Miller, R.E., AE5
Mirza, M.Y., EF11
Miskin, J., CD4
Mitchel, G., AF9
Mitchell, J.B.A., DF9,11,12
Mo, J.N., CD3
Moisan, M., BEI,2
Monaro, S., BD11; CDl.ll
Montgomery, D.S., BF8
Moorcroft, D.R., FA2; EE3
Moore, R.A., AG6,7
Moore, R.B., CD4
Morrison, J.A., EA4
Muir, W.B., CG6
Mul, P., DF9,11,12; EE9
Nain, V., CH2
Nelson, E., DC1
Neubecker, K., DF1
Neufeld, C.R., CF4
Ng, A.K.H., CF6,7
Nicholls, R.W., EE6.10
Nicoll, D.W., BF10
Noel, P., CF4
Normandin, R., EH11
Novak, J.P., BE6
Noxon, J.F., FA3
O'Donnell, P., DD2
Offenberger, A.A., CF6,7
Ogram, G.L., BE5
Oka, T., AE3
Olin, A., CC3,4
Oram, C.J., CC5
Oyedele, J.A., BF5
Pace, P., EF3
Pajkowski, H.R., CH3
Pal, S.R., EE11
Palcic, B., DC3
Palser, R., AD2
Pant, M.M., CG2,3
Pantel, R., BEI
Paradis, P., BD11; CDl.ll
Parbhakar, K.J., AF2
Parsons, R.R., EB4
Pathak, B.P., CD9
Pathria, R.K., CH3
Patterson, M.S., BC5
Paul, D.A.L., DF8
Paul, W., CGI
Pearce, R.M., CC3,4
Peemoeller, H., DEI
Pendyala, S., DG9,10
Pepin, H., AFl
Perz, J.M., AG8
Petch, H.E., BF1
Piché, M., EF7
Pigeon, R., BD4
Pintar, M.M., BF10; DEI
Pitt, L., CF6,7
Pocobelli, G., EG5
Ponomarenko, A.G., EG9
Poutissou, J.-M., BD1
Prasad, E.J., BF2; CG4; DG8
Quist, R., CG4
Ransay, W.D., CD2; DF7
Rand, S.C., CH9
Rashid, K., DE2
Razavi, F.S., AG5
Read, L.A.A., CE3
Reay, N., CC2
Redner, S., EA1
Reesor, G.E., AE2; CE3
Reid, J.D., AG6,7
Reifenberger, R., AG9
Reynhardt, E.C., BF1
Rheault, F., AFl
Ricard, A., BE2
Richardson, J.R., CC5
Richardson, M.C., AF3,4,5,6,7,8
Rioux, C., BD4
Robert, A., CF4
Robertson, L.P., CC5
Robertson, R.G.H., EC1
Rogers, D.W.O., BC7
Rosner, S.D., DF3
Rostoker, G., EE1
Rostworowski, J.A., BG6,7
Roth, A.P., BG8
Rowe, D.J., BB1
Rowell, N., BAI ; EH9.10
Rowlands, J.A., AGI
Roy, R., BD4
Ryan, J.S. , EE11
Sabev, C., CC4
St-Jacques, R.G., DG3
Salomon, M., BD1
Salzmann, D., CF6.7
Samson, J.C., AF10; CF5
Sanderson, F., BE10
Santry, D.C., CD7
Sargeant, W.J., EF5,6
Sayer, M., AA2; CG4; DG8; EB3
Schaber, H. , BG2
Scherm, R., CHI
Schneider, M.H., BF12
Schnopper, H.W., CE10
Schreiner, L.J., DEI
Schulte, C.W., DG1,5
Schultz, R.J., DG6
Schwenk, H., DF1
Scoles, G., AE5
Segel, S.L., BF4
Sharma, H., CD3
Sharp, A.R., BF12
Shelton, D.P., AE1
Shepherd, G.G., EE7,8
Shewchun, J., BG9
Shoucri, M.M. , BE6; CF1; EG8
Shragge, P.C., BC5
Sills, M., CE8
Sipe, J.E., CH8
Sivasankar, V.S., DG2
53
Skarsgard, L.D., DC3
Skensved, P., BD7
Slobodrian, R.J., BD4
So, V., CE6; EH11
Sofia, K., CD6
Sofko, G.J., CB3
Song, K.S., CH7
Soper, A.K., CH6
Sourkes, A.M., BC3
Sperry, W.C., CC4
Springthorpe, A.J., BG1
Srivastava, R.P., DF4
Stairs, D., CCI
Stansfield, B.L., EG1,2
Stegeman, G.I.A., AB3; BAI; CE6;
EH4,9,10,11
Stewart, A.T., DG4
Stewart, N.M., CC5
Stinson, M.R., AG2
Stinson, R.H., GA1
Stoicheff, B.P., CH9; DF2; EF4
Subba Rao, B.N., CD6
Svensson, E.C., CHI
Szarka, F., CE2
Szili, Z., BE6
Tabisz, G.C., AE1
Talman, J.D., DF5,6
Taole, S.H., AG12
Taylor, K., BC1
Taylor, R.S., AG12; EF5
Taylor, T., BD8,10
Taylor, W.L., CH2.5
Teh, G.A., CE6; EH11
Teichmann, J., EG6
Teitsma, A., CH4
Tenti, G., CH11
Terreault, B., DG3
Teshima, K., BE4
Thewalt, M.L.W., BG7
Thomas, P.J., EH10
Thouless, D.J., BB4
Tomchuk, E., BF9
Tomin, V.I., EF6
Tomov, I.V., AF4
Tong, B.Y., CG2.3
Tremblay, R., CE7
Tsai, J.S., DF8
Tunaley, J.K.E., CB4
Van Andel, H.W.H., EG4,6
Van Driel, H.M., BG4,5; EH10
Van Dyk, G., BC5
Van Oers, W.T.H., AC2
Varley, B., CD4
Vasudev, R., AE9
Verge, C., AG4
Verly, P., CE7
Videla, N., CD2; DF7
Villeneuve, D.M., AF3
Vincent, D., CE4
Vincent, J.S., CC3
Waddington, J.C., CD10
Walker, J.D., BH; GA3
Walker, M.B., BF8; DA2
Wallace, S.C. , EF4
Ward, D., EC3
Watters, J.F., DG6
Watton, A., BF1
Webb, J.B., BG12
Webster, A.R., EE5
Weinberger, E., DF2
Wendling, R.D., DF1
Westwood, W.D., AB2
Whippey, P.W., DG2
White, B.L., DF1
Whitmore, M.D., AG11
Wiegand, C., CC4
Williams, D.F., BG12
Wodrich, R., DF1
Woloshyn, R.M., EC4
Wong, M., AE2
Wood, B.M., CH10
Woods, A.D.B., CHI
Woods, S.B., AGI
Woo1ley, J.C., BG1.10
Yaffe, M., ED4
Yeh, K.C., CB2
Yen, R., BD3
Zakrzewski, Z., BEI
Zauhar, J., BG11
Zuckerraann, M.J., CG6
Zuk, W.M., BC2
NOTES
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Telephone: 416/625-3901
Telex: 06-960-126
S e e t h e 1 1 7 0 at C A P Congress, London, Ontario
1 2 - 1 5 June 1978.
McMASTER UNIVERSITY
D E P A R T M E N T OF
CHEMISTRY
Applications are invited
positions in Chemical Physics:
for
post-doctoral
1) To carry out fundamental research in heterogeneous catalysis using LEED, AES and desorption
spectroscopy, with Dr. P. T. Dawson; and
2) To carry out research upon single and multiple
photon high resolution electronic absorption spectroscopy of molecules, with Dr. G. W. King, using
continuous and pulsed tunable dye lasers.
Stipend $ 1 0 , 0 0 0 to $ 1 1 , 0 0 0
Applicants should submit curriculum vitae
and names of three references to:
Dr. D. B. MacLean, Chairman
Department of Chemistry
McMaster University
Hamilton, Ontario
Canada L8S 4 M 1
POSTDOCTORAL
RESEARCH
FELLOWSHIP
POSITIONS
Theoretical and experiemental
Postdoctoral
Fellowship positions are available in the fields of atmospheric physics, biophysics, geophysics, high
energy physics, molecular physics, quantum optics,
relativity and solid state physics. Stipends are up to
$ 1 1 , 1 0 0 per annum.
APPLY T O :
i
Prof. R. L. Armstrong
Chairman
Department of Physics
University of Toronto
Toronto, Ontario M 5 S 1A7
POSTDOCTORAL
FELLOWSHIPS
and
RESEARCH ASSOCIATE
POSITIONS
in Battery Research
Two vacancies exist in my research group for outstanding individuals interested in doing fundamental research related to the development of a new
rechargeable electrical storage battery. Candidates
should have prior research experience in some area
of Condensed Matter Physics, Chemical Physics or
Engineering Physics. The appointments are initially
for one year but may be renewed. Preference will
be given to Canadians.
Applications, including a Curriculum Vitae and the
name of three referees, should be sent to:
R. R. Haering
Department of Physics
University of British Columbia
2 0 7 5 Wesbrook Mall
Vancouver, B.C.
V6T 1 W 5
PHYSICS
FACULTY
POSITION
The University of Guelph Physics Department invites applications for a tenure-stream position,
probably at the Assistant Professor level, to commence in the Fall of 1978. The position is subject
to final budgetary approval. The successful applicant will be expected to teach at both the undergraduate and graduate level and to conduct a
program of experiemental or theoretical research in
one of the following areas: atomic or molecular
physics, biophysics, liquid or solid state physics,
ion-solid interactions, nuclear or particle physics. A
full resume, including the names of at least three
references, should be sent to:
The Chairmen
Department of Physics
University of Guelph
Guelph, Ontario N1G 2 W 1
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PROFESSEUR EN
PHYSIQUE NUCLÉAIRE
EXPÉRIMENTALE
Le d é p a r t e m e n t d e p h y s i q u e d i s p o s e d ' u n poste d e
p r o f e s s e u r à c o m p t e r de juin 1 9 7 8 Ce professeur sera
a p p e l é à diriger une équipe d e recherche en physique
nucléaire e x p é r i m e n t a l e et à p o u r s u i v r e d e s recherches à
l'aide d ' u n accélérateur V a n d e Graaff II sera aussi
appelé à participer à l ' e n s e i g n e m e n t e n physique a u
niveau du B.Sc., d u M.Se. et d u Ph D. et à collaborer aux
diverses activités du d é p a r t e m e n t de physique. Le titre
universitaire sera en f o n c t i o n de l'expérience du candidat.
W ' ^ W w r
UNIVERSITY OF
SASKATCHEWAN
PLASMA PHYSICS
LABORATORY
A p p l i c a t i o n s are invited for t h e f o l l o w i n g p o s i t i o n s :
Research
Associate:
Experimental
plasma
Le c a n d i d a t d o i t posséder un Ph D et être un chercheur
qui a d é m o n t r é une excellente c o m p é t e n c e en p h y s i q u e
nucléaire e x p é r i m e n t a l e à l'aide d ' u n accélérateur. La
p r é f é r e n c e sera accordée à un c h e r c h e u r senior. La c o n naissance d e la langue française parlée e t écrite e s t
nécessaire.
physicist, preferably w i t h postdoctoral experience,
to w o r k o n existing a n d planned
toroidal
experiments. Salary comparable t o professorial
ranks.
Le l a b o r a t o i r e possède un V a n de Graaff de 7 M V qui
p r o d u i t des faisceaux allant de H + à A r ++ + . U n e source
de 3 H e polarisés est en p r o j e t Les recherches p o r t e n t sur
la s p e c t r o s c o p i e et les r é a c t i o n s nucléaires, les s y s t è m e s
à petit n o m b r e d e corps e t les p h é n o m è n e s d e polarisation.
a n d / o r i n t e r e s t in m a c h i n e d e s i g n , t h e d e v e l o p m e n t
A d r e s s e r son c u r r i c u l u m vitae et les n o m s de trois répond a n t s avant le 3 1 m a i 1 9 7 8 à
Professeur C l a u d e S t - P i e r r e
D é p a r t e m e n t de Physique
Université Laval
C i t é Universitaire
Québec G 1 K 7 P 4
Canada
Engineer o r physicist: Applicants w i t h experience
of d i a g n o s t i c e q u i p m e n t a n d d a t a h a n d l i n g s y s t e m s
preferred.
and
Salary
commensurate
with
experience
qualifications.
Applications including curriculum vitae and
of three references t o b e sent t o :
H. M. Skarsgard
Physics Department
University of Saskatchewan
Saskatoon, Canada
names
I *
National Research
Council Canada
Conseil national
de recherches Canada
I *
Conseil national
de recherches Canada
National Research
Council Canada
RESEARCH
ASSOCIATES
ATTACHES DE
RECHERCHE
available for posts
in Industry,
Government and Universities
disponibles pour des postes
industriels, gouvernementaux et
universitaires
A l i m i t e d n u m b e r of h i g h l y - q u a l i f i e d y o u n g
researchers in the natural sciences a n d e n g i n e e r i n g w i l l
b e c o m e available for e m p l o y m e n t as their Associateships t e r m i n a t e d u r i n g 1 9 7 8
Un n o m b r e limité de jeunes chercheurs h a u t e m e n t
qualifiés dans les sciences naturelles et le génie seront
disponibles pour e m p l o i à la fin de leur stage c o m m e att a c h é de recherche au cours de 1 9 7 8 .
These Research A s s o c i a t e s originally w o n National
Research Council c o m p e t i t i o n s a n d w e r e s e l e c t e d f r o m a
large n u m b e r o f c a n d i d a t e s on t h e basis of t h e i r superior
a c a d e m i c records and their d e m o n s t r a t e d ability t o perf o r m original research of h i g h calibre in t h e i r c h o s e n
f i e l d s Research Associates are a p p o i n t e d for a one-year
t e r m , r e n e w a b l e on an a n n u a l basis for a t o t a l tenure n o t
to e x c e e d f i v e years. On average they s p e n d t w o years in
a n NRC l a b o r a t o r y .
Ces attachés de recherche avaient été sélectionnés
sur c o n c o u r s par le Conseil n a t i o n a l de recherches p a r m i
un grand n o m b r e de c a n d i d a t s sur la base de leur
excellent dossier universitaire et de leur c a p a c i t é d é m o n trée à e f f e c t u e r des travaux de recherche originaux et de
grande qualité dans le d o m a i n e choisi. Les attachés de
recherche sont n o m m é s pour une période d ' u n e année,
renouvelable a n n u e l l e m e n t , j u s q u ' à c o n c u r r e n c e d ' u n e
durée m a x i m a l e de cinq ans. La durée m o y e n n e d u stage
dans un laboratoire du CNRC est de deux ans.
I n t e r e s t e d e m p l o y e r s are invited to c o n t a c t the
O n invite les e m p l o y e u r s intéressés à c o m m u n i q u e r
avec le
Conseil national de recherches
du C a n a d a
O t t a w a , Ontario K 1 A 0 R 6
N a t i o n a l Research Council of C a n a d a
O t t a w a . Ontario K l A 0 R 6
THE UNIVERSITY OF
CALGARY
UNIVERSITY OF
ALBERTA
D E P A R T M E N T OF PHYSICS
The D e p a r t m e n t o f Physics c u r r e n t l y has 4 5 faculty
m e m b e r s d o i n g research in the general areas of
Geophysics. Nuclear Physics. L o w T e m p e r a t u r e a n d
Solid
State
Physics, Theoretical
Physics
and
Astrophysics.
VISITING APPOINTMENTS:
Each year t h e D e p a r t m e n t has a f e w v i s i t i n g app o i n t m e n t s at the A s s i s t a n t , A s s o c i a t e or Full
Professor levels. These a p p o i n t m e n t s are for oneyear only. Interested c a n d i d a t e s s h o u l d s u b m i t an
a p p l i c a t i o n a n d c u r r i c u l u m vitae by N o v e m b e r 15.
P O S T - D O C T O R A L F E L L O W S H I P S 8< RESEARCH
A S S O C I A T E S HI PS:
A v a i l a b l e in s o m e areas o n a n o n - p e r m a n e n t basis.
GRADUATE STUDENTS:
Inquiries are w e l c o m e .
available
Financial
assistance
Chairman,
D e p a r t m e n t of Physics,
University of A l b e r t a ,
Edmonton, Alberta T 6 G 2 J 1
Acoustics
A s t r o p h y s i c s (Theoretical and observational)
Atmospheric
Physics ( A c o u s t i c
s o u n d i n g , atm o s p h e r i c spectroscopy, s t r a t o s p h e r i c studies
both ground-based and balloon-borne)
Biophysics ( M a m m a l i a n heart m o r p h o l o g y . light
s c a t t e r i n g studies)
Electron Paramagnetic Resonance
Space Physics (Satellite, rocket, balloon. and
g r o u n d - b a s e d studies)
Theoretical Physics
X-ray Crystallography
is
For f u r t h e r i n f o r m a t i o n o n any of t h e above, please w r i t e :
Dr. W . J o h n M c D o n a l d ,
The D e p a r t m e n t o f Physics invites s t u d e n t s to apply for
entry i n t o M.Sc. and Ph.D. p r o g r a m m e s in Physics.
Research areas include:
Assistantships available
to:
For further i n f o r m a t i o n ,
write
C h a i r m a n , G r a d u a t e Affairs C o m m i t t e e
D e p a r t m e n t of Physics
University of Calgary
Calgary, A l b e r t a T 2 N 1 N 4
Advanced "Book Program
È
CONCEPTUAL FOUNDATIONS Of
OUANTUM MECHANICS
SECOND EDITION, Completely
revised,enlarged, reset
Tt
eC
B e r n a r d d ' E s p a g n a t , University
of Paris, Orsay
MATHEMATICAL
PHYSICS
MONOGRAPH
SERIES, No. 20
A text for an advanced u n d e r g r a d u a t e course in
the P h i l o s o p h y of Science, or a s u p p l e m e n t a r y
w o r k for any first year course in Q u a n t u m
Mechanics, this v o l u m e is an enlarged and revised e d i t i o n of Professor d'Espagnat's i n t r o d u c t i o n to a n d r e v i e w of the c o n c e p t u a l p r o b l e m s
associated w i t h the q u a n t u m theory of measurement. The changes from a n d a d d i t i o n s to the
first e d i t i o n are q u i t e substantial. Exercises are
i n c l u d e d . A u t h o r a n d Subject Indexes.
". . . r e c o m m e n d t h e b o o k u n r e s e r v e d l y to anyo n e i n t e r e s t e d in s u r v e y i n g q u a n t a ! f o u n d a t i o n s
p r o b l e m s
"
A m e r i c a n Scientist
C O N T E N T S : E l e m e n t s of Q u a n t u m
M e c h a n i c s — M a t t e r Waves. S u p e r p o s i t i o n and
L i n e a r i t y . Statement of the Rules. Comments.
Alternative Formulations. Density Matrices a n d
M i x t u r e s — T h e Density M a t r i x Formalism. M i x tures Q u a n t u m N o n s e p a r a b i l i t y — T h e
Einstein-Podolosky-Rosen Problem. Possible
V i e w s on N o n s e p a r a b i l i t y . I n d i v i d u a l s . Ensembles. States. T h e " H i d d e n V a r i a b l e s " A p p r o a c h .
Direct S t u d y of Some Principles. Aspects of the
Problem of R e t r o d i c t i o n . M e a s u r e m e n t
T h e o r i e s — E l e m e n t s of Measurement T h e o r y .
Classical Properties. M a c r o s c o p i c Instruments.
O f Cats and Pointers. N o n i d e a l Measurements:
S m a l l Influence of O u t s i d e W o r l d . K n o w l e d g e
a n d the P h y s i c a l W o r l d — R e a l i t y a n d Objects.
Positivism. Bohr and Heisenberg. W i g n e r ' s
Friend. T h e R e l a t i v i t y of States. S u m m a r y a n d
Outlook.
1976, x x x i v . 334 pp..
illus.
Hardbound
0-805-32384-8
$27.50
P a p e r b o u n d 0-805-32383-X
$17.50
NUCLEI and PARTICLES
An introduction to Nuclear and
Subnuclear pnysics
SECOND EDITION, Revised,enlarged, reset
E m i l i o G. S e g r è
U n i v e r s i t y of California
at Berkeley
For nuclear and particle physicists, nuclear
chemists, graduate students, a n d researchers interested i n data or r a p i d o r i e n t a t i o n i n subjects
outside t h e i r i m m e d i a t e specialization, this volu m e presents a c o m p r e h e n s i v e v i e w of nuclear
and particle physics w h i c h is r e a d i l y accessible
a n d useful to the prospective researcher. There
is a b i b l i o g r a p h y a n d problems at the end of
each chapter plus A u t h o r and Subject Indexes.
C O N T E N T S : T o o l s — T h e Passage of Radiations
t h r o u g h Matter. Detection M e t h o d s for N u c l e a r
Radiations. Particle Accelerators. Radioactive
Decay. T h e N u c l e u s — E l e m e n t s of the Nuclear
Structure a n d Systematics. A l p h a Emission.
Gamma Emission. Beta Decay. The T w o - B o d y
Systems and N u c l e a r Forces. Nuclear Reactions.
Neutrons. P a r t i c l e s — I n t r o d u c t i o n to Particle
Physics. Leptons. Pions and Other Bosons.
Baryons. Classification of Hadrons, Quarks, and
SU (3). F o r m Factors and e* e Collisions. Weak
Interactions Revisited. H i g h - E n e r g y
C o l l i s i o n s of Hadrons.
N o v e m b e r 1977, xx, 966 pp., i l l u s .
H a r d b o u n d 0-805-38601-7
$29.50
SCATTERING THEORY in
OUANTUM MECHANICS
Physical Principles and Mathematical Methods
W. O. A m r e i n , University
of Geneva
J. M. ) a u c h , late of University
of Geneva
K. B. S i n h a , University
of Geneva
LECTURE N O T E S A N D SUPPLEMENTS
IN
PHYSICS SERIES. No. 15
T h i s book explains the concepts of q u a n t u m
scattering theory, develops the m a t h e m a t i c a l
tools for t h e i r d e s c r i p t i o n , a n d derives properties of various p h y s i c a l q u a n t i t i e s w i t h mathe m a t i c a l l y rigorous methods. It is designed for
physicists and m a t h e m a t i c i a n s at or above the
second-year graduate level a n d can be used as
a textbook.
CONTENTS: Introductory Material—Physical
Heuristics. Hilbert Space a n d Linear Operators.
One-Parameter U n i t a r y Groups and Free Particles. G e n e r a l F o r m u l a t i o n of S i n g l e - C h a n n e l
S c a t t e r i n g S y s t e m s — T i m e - D e p e n d e n t Scatteri n g T h e o r y . Spectral T h e o r y of S e l f - A d j o i n t
Operators. T i m e - I n d e p e n d e n t Scattering T h e o r y .
Position in Scattering T h e o r y . S p e c i a l T o p i c s in
Potential S c a t t e r i n g — S e l f - A d j o i n t n e s s , Existence of Wave Operators. A s y m p t o t i c Completeness. E i g e n f u n c t i o n Expansions. S p h e r i c a l
S y m m e t r y in Scattering T h e o r y . Scattering at
H i g h a n d at I.ow Energies. Scattering T h e o r y for
L o n g Range Potentials. M u l t i c h a n n e l S c a t t e r i n g
S y s t e m s — G e n e r a l F o r m u l a t i o n of M u l t i c h a n n e l
Scattering. M u l t i c h a n n e l Potential Scattering.
T h e T h r e e - B o d y Problem. B i b l i o g r a p h y .
N o t a t i o n Index. Subject I n d e x .
1977, x i v , 691 pp., i l l u s .
Hardbound
0-805-30202-6
Paperbound
0-805-30203-4
$29.50
$17.5 0
OUALITATIVE METHODS in
OUANTUM THEORY
A. B. M i g d a l
Translated f r o m the Russian e d i t i o n by A n t h o n y
J. Leggett, University
of Sussex
FRONTIERS I N PHYSICS SERIES. No. 48
T h i s u n i q u e book, w r i t t e n for graduate students
by a leading Soviet theorist, is not a textbook of
ciuantum mechanics but rather a c o m p e n d i u m of
the " t r i c k s of the t r a d e " w h i c h a l l p r a c t i c i n g
theoretical physicists use. but few nave trieii to
set d o w n systematically in w r i t i n g . The emphasis t h i o u g h o u t is on the d e v e l o p m e n t of
q u a l i t a t i v e feeling for p r o b l e m s t h r o u g h the use
of o r d e r - o f - m a g n i t u d e estimates, s i m p l i f i e d
models and s y m m e t r y considerations.
" T h i s b o o k s h o u l d be required r e a d i n g for a n y
s e r i o u s g r a d u a t e s t u d e n t in t h e o r e t i c a l
physics."
Nature
CONTENTS: Dimensional and " M o d e l " Approximations. Various Types of Perturbation T h e o r y .
The Quasiclassical A p p r o x i m a t i o n . T h e A n a l y t i c
Properties of Physical Quantities. M e t h o d s in
the M a n y - B o d y Problem. Q u a l i t a t i v e M e t h o d s i n
Quantum Field Theory.
1977, x x i v , 440 pp., illus.
H a r d b o u n d 0-805-37064-1 $21.50
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somewhat from those listed, reflecting d i s t r i b u t i o n costs and currency
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Applications are invited for research in the above
areas. These fellowships or assistantships carry a
stipend in accord with N.R.C. regulations and will
be tenable for one year with renewal for a second
year by mutual agreement.
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POSITION
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The INSTITUTE OF PARTICLE PHYSICS OF
CANADA invites applications for Research Scientist positions. Applicants should have proven ability
in Experimental Particle Physics. Initial appointments will be for three years followed by a
review which, if favorable, will lead to a continuing
career appointment. Initially Research Scientists
will be expected to join one of the existing I P.P.
collaborations at Fermilab or SLAC but the opportunity to initiate new experiments will also exist.
Applications including curriculum vitae. transcripts
and the names of 3 referees should be sent to
J. D. Prentice
Department of Physics
University of Toronto
Toronto, Ontario M 5 S 1A7
Canada
Applications are invited from persons w i t h
experience in the areas of theory of liquid and
amorphous electronic conductors, and theory of
evolution of biological macromolecules Salary and
nature of appointment (PDF or RA) dependent
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Please send resume, publication list, and names of
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Department of Physics
Simon Fraser University
Burnaby, B.C., Canada V5A 1S6
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The INSTITUTE OF PARTICLE PHYSICS OF
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Associate Positions. Openings exist in the Canadian experimental particle physics groups located
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Toronto, Ontario M 5 S 1A7
Canada
UNIVERSITY OF
SASKATCHEWAN
G E R H A R D HERZBERG FELLOWSHIPS
FOR G R A D U A T E STUDY
In h o n o u r of Dr. Gerhard Herzberg. 1 9 7 1 Nobel
Laureate in Chemistry, and to c o m m e m o r a t e his service
to Saskatchewan, the University of Saskatchewan offers a
g r a d u a t e f e l l o w s h i p v a l u e d at $ 7 , 0 0 0 per a n n u m ,
r e n e w a b ' e for a s e c o n d year The f e l l o w s h i p is t e n a b l e in
t h e D e p a r t m e n t of Physics or the D e p a r t m e n t of
C h e m i s t r y a n d C h e m i c a l Engineering
by a candidate for a
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to the Fellow.
Letters of a p p l i c a t i o n w i t h a p p r o p r i a t e d o c u m e n t a t i o n a n d t h e n a m e s of t w o references s h o u l d be addressed to
Ealing
PNUMOUNT
Precision suction mounts for
the optical laboratory.
ÉL
C o l l e g e of G r a d u a t e Studies and Research
University of S a s k a t c h e w a n
Saskatoon, Saskatchewan
Canada S 7 N 0 W 0
M c M A S T E R UNIVERSITY
POST D O C T O R A L FELLOWSHIPS
AND
RESEARCH A S S O C I A T E S H I P S
Applications are invited for post doctoral
fellowships and research associateships in
the Physics Department. Areas of research
include theoretical physics, solid state
physics, nuclear physics, quantum optics,
mass spectrometry, chemical physics and
astrophysics. Experimental research at
McMaster features a tandem accelerator, a
swimming-pool reactor and the Institute of
Materials Research.
Applications, including curriculum vitae and
the names of three referees should be sent
to.
This novel concept in optical mounting makes it
possible to attach equipment to granite or plastic
laminate surfaces.
Pnumount. . .
will adhere for 24 hours or more,
will support offset loads of 2kg at 100mm.
are interferometrically stable.
Furthermore, they will accept the wide range of
Ealing mounts many of which you may already own.
Pnumounts have all the advantages of switchable
magnets yet they don't require a magnetic table
surface.
9 6 4 9 Côte de Liesse, Dorval H 9 P 1 A3, Québec
S o u t h Natick, Mass. 0 1 7 6 0 , Tel: ( 6 1 7 ) 6 5 5 - 7 0 0 0
U n i t No. 5, Carlingview Drive, R e x d a l e M 9 W 5 E 7 , O n t a r i o
Dr. M. F.
Chairman,
McMaster
Hamilton,
Collins
Department of Physics
University
Ontario L 8 S 4 M 1
Greycaine Road, W a t f o r d , W D 2 4PW, E n g l a n d
B a h n h o f s t r 8, Postfach 1 2 2 6 , 6 1 2 8 Hochst, W. G e r m a n y
1031, Boulevard Jeanne d ' A r c , 5 9 5 0 0 DOUAI, France
ROYAL ROADS
MILITARY COLLEGE
COASTAL M A R I N E
SCIENCE LABORATORY
T E A C H I N G POST
DOCTORAL FELLOWSHIP
AND
PART T I M E
TEACHING POSITION
A Teaching Post D o c t o r a l Fellowship w i l l be available for
research in t h e o r e t i c a l solid state physics, specifically
t r a n s p o r t properties in metals, for one year. The t e a c h i n g
of one course at first or second year level is required.
Requires a post d o c t o r a l research associate to study t h e
d y n a m i c processes, physical properties a n d b o t t o m
s t r u c t u r e s of B.C. coastal estuaries. This is initially a one
year a p p o i n t m e n t , s u p p o r t e d by D e f e n c e Research Board
funds.
It is necessary for an applicant to have a g o o d p u b l i c a t i o n
record, and to be capable o f rapidly d e v e l o p i n g a n d coord i n a t i n g t h e College's e x i s t i n g p r o g r a m s in this field.
Salary $ 1 5 . 0 0 0 range Replies t o :
Prof. H. J. Duffus, H e a d
Physics D e p a r t m e n t
Royal Roads M i l i t a r y C o l l e g e
F M O Victoria. B C
VOS 1 BO
THE BUBBLE CHAMBER GROUP
AT THE UNIVERSITY OF TORONTO
HAS A VARIETY OF FILM
SCANNING A N D MEASURING
EQUIPMENT. INCLUDING OPTICAL
PROJECTORS A N D PRECISION
M A N U A L L Y OPERATED STAGES.
THIS EQUIPMENT IS A V A I L A B L E
FOR THE COST OF
TRANSPORTATION. IN ADDITION
THERE IS SOME OLD BUBBLE
CHAMBER FILM, W H I C H M A Y BE
USEFUL FOR TEACHING
PURPOSES.
CONTACT
Dr. A. W . Key
Physics Department
University of Toronto
Toronto, Ontario
M 5 S 1A7
TEL.: ( 4 1 6 - 9 7 8 - 2 9 5 4 )
W e also require a person w i t h a Ph D. to teach one or
t w o half courses at the first or s e c o n d year level in the fall
t e r m ( S e p t e m b e r - D e c e m b e r , 1 9 7 8 ) . There is a possibility
t h a t a similar r e q u i r e m e n t w i l l exist in the spring t e r m
(January-April, 1979).
A p p l i c a t i o n s , i n c l u d i n g c u r r i c u l u m vitae, transcripts, and
t h e n a m e s of three referees, s h o u l d be sent, not later
than June 20, 1978, to:
J. E. Black
Chairman
Physics D e p a r t m e n t
Brock University
St. Catharines, Ontario
L2S 3 A 1
QUEEN'S UNIVERSITY
METALLURGICAL ENGINEERING
DEPARTMENT
Research Associate
A Research Associate position is available in the
Metallurgical Engineering Department at Queen's
University to work on the welding of steel rails by
an adaptation of the electroslag process. Candidates should be experienced in experimental
physics and willing to apply their skills to this
process as it undergoes its development. The appointment is for one year in the first instance, with
a possible second year pending continued funding
of the project. The salary is negotiable. Interested
parties should submit detailed résumé and the
names of two referees to:
Dr. W. G. Henry
Head
Metallurgical Engineering Department
Queen's University
Kingston, Canada
K7L 3 N 6
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100K
10K
Without Pileup Rejector
£
1K
100
With Pileup Rejector
J_
10
10
_L
Energy (MeV)
-l.T2.0
B a c k g r o u n d Reduction Obtained from Pileup Rejection.
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572 to generate very symmetrical outputs over a w i d e
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>35
~
2 3.0
II 25
5
I
n
1—I I I I I I
i
1—r
+ 1.0 >
a;
£
+0 5
0
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3 2 . 0
0)
cc
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PEAK S H I F T
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1K
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ra
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Typical R e s o l u t i o n a n d B a s e L i n e S t a b i l i t y v s C o u n t i n g R a t e
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W h y not call us, and w e can discuss this and our two
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essentially t h e same as the 572 but without the pileup
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technical assistance call our special TLC lines—(615)
482-9071 from Western States, 9072 from S o u t h and
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n
Physical Sciences Division
76 OFFICES IN 49 COUNTRIES
7045
<C 1977. Ortec
I
radionics limited
Montréal
195 Graveline Street
Montréal, Québec H4T 1 R6
Tel 5 1 4 - 7 3 5 - 4 5 6 5 — Telex
05-827558
EXCLUSIVE CANADIAN
Toronto
1 1 1 1 Finch Ave. West. Suite 3 0 7
D o w n s v i e w , Ontario M 3 J 2 E 5
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REPRESENTAT!VE
Ottawa
2 4 8 7 Kaladar Ave., Suite 2 0 5 / 2 0 6
Ottawa, Ontario K1V 8 B 9
Tel
613-521-8251
Winnipeg
P.O. Box 8 1 2
Winnipeg. Manitoba R3C 2 N 4
Tel 2 0 4 - 4 7 5 - 1 7 3 2
Vancouver
2 1 8 2 West 12th Ave.
Vancouver, B.C. V6K 2 N 4
Tel 6 0 4 7 3 2 - 7 3 1 7 — Telex
04-54573
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