solid state nuclear track detectors

Transcription

SOLID STATE
NUCLEAR TRACK DETECTORS
ORGANIZING COMMITTEE
R. SCHMITT
H. FRANCOIS
N. KURTZ
J.P. MASSUE
M. MONNIN
E. SCHOPPER
Universite de Lyon
Commissariat a l'Energie Atomique
Fontenay-aux-Roses
Centre National de la Recherche Scientifique
Strasbourg
Conseil de l'Europe - Strasbourg
Clermont-Ferrand
Institut fiir Kernphysik - Frankfurt
SCIENTIFIC COMMITTEE
F. CAMBOU (France); H. FRANQOIS (France); N. KURTZ (France);
L. JAUNEAU (France); NARCHAND (France); Y. CAUCHOIS (France);
A. ASTIEk (France); R. SCHMITT (France); M. MONNIN (France);
GAUVENET (France); TEYSSIER (France); V. GANDIA (Spain);
M. VARNAGY (Hungary); E. SCHOPPER (Federal Republic of
Germany); GUZAKOW (France); M. SCHARMANN (Federal Republic
of Germany); I. OTTERLUND (Sweden); S. A. DURRANI (United
Kingdom); E.V. BENTON (U.S.A.); G0L0VAN0VA (U.S.S.R.);
R. KATZ (U.S.A.); J.P. MASSUE (France)
THE CONGRESS WAS SPONSORED BY
Le Recteur de 1'Academie de Lyon
Assemblee Parlementaire du Conseil de l'Europe
Centre National d'Etudes Spatiales
Gesellschaft fiir Strahlen und Umweltforschung
ORGANIZING SECRETARIAT
Mmes et Melles M. COBUT; F. OHLMANN; S. PFISTER; V. PEREIRA; M. MICHELSEN
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SOLID STATE
NUCLEAR TRACK DETECTORS
Proceedings of the 10th International Conference,
Lyon, 2-6 July 1979
Edited by
H. FRANCOIS
N. KURTZ
Commissariat d I'Energie Atomique, Fontenay awe Roses
Centre de Recherches Nude"aires, Strasbourg
J. P. MASSUE
M. MONNIN
Council of Europe, Strasbourg
Centre National de la Recherche Scientifique, Aubiere
R. SCHMITT
S. A. DURRANI
University Lyon I, Villeurbanne
University of Birmingham
PERGAMON PRESS
O X F O R D • N E W Y O R K • T O R O N T O • S Y D N E Y • PARIS •
FRANKFURT
U.K.
Pergamon Press Ltd., Headington Hill Hall,
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FEDERAL REPUBLIC
OF G E R M A N Y
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C o p y r i g h t © 1980 Pergamon Press Ltd.
All Rights Reserved. No part of this publication may be
reproduced, stored in a retrieval system or transmitted
in any form or by any means: electronic,
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without permission
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the
publishers.
First edition 1980
British Library Cataloguing in Publication Data
International Conference on Solid State Nuclear
Track Detectors, 10th, Lyons, 1979
Solid state nuclear track detectors.
1. Solids, Effect of radiation on - Congresses
2. Particle tracks (Nuclear physics) - Congresses
I. Title
II. Francois, H
79-41577
QC176.8.R3
539.7'7
ISBN 0-08-025029-7
In order to make this volume available as economically
and as rapidly as possible the authors' typescripts have
been reproduced in their original forms. This method
has its typographical limitations but it is hoped that they
in no way distract the reader.
Published as supplement N o . 2 to the journal Nuclear
Methods,
Instruments
and Applications
Tracks:
(formerly Nuclear
Track
Detection)
Printed in Great Britain by A. Wheaton & Co. Ltd., Exeter
CONTENTS
List of participants
XIX
OPENING SESSION
SESSION 1: FUNDAMENTAL MECHANISMS
Chairman: P. Bogomolov
Determination of the screening
parameter from measurements of
differential energy loss
13
Solid krypton emission chamber
29
A. Chambaudet
Ph. Romary
Correlation of registration threshold
with crystallinity state of plastic
detectors
35
A. Chambaudet
J. Roncin
Radicals in teflon following heavy
ion or energetic electron bombardment.
Correlation with latent tracks
41
F. Granzer
E. Schopper
Th. Wendnagel
Properties and Technology of
monocrystalline AgCl detectors
1. Aspects of solid state physics
47
R. Katz
R.L. Rosman
A.S-F. Li
Y-L. Chang
Supralinearity and LET discrimination
in radiation measurements
57
A. Aframi an
A.I.
O.K.
L.I.
V.P.
B.U.
Bolozdynia
Egorov
Sokolov
Miroshnichenko
Rodionov
V
vi
Contents
J.P. Moliton
C. Boutinaud
J-L. Decossas
J.C. Vareille
J-L. Teyssier
B. Delaunay
Connaissances actuelles sur les
acetates de cellulose en tant que
detectuers sol ides de traces
67
M. Chi para
D. Hasegan
M. Velter-Stafanescu
E.S.R. studies in electron beam
irradiated lexan
75
K.O. Groeneveld
E. Schopper
S. Schumann
Atomic displacement effects from heavy
ion induced coulomb explosion
81
SESSION 2: METHODOLOGY OF DETECTORS
SESSION 2.1: EMULSIONS AND ClAg CRYSTALS
Chairman: E. Schopper
Determination of Z > 6 particles flux
in emulsion layers under the action of
pulsed electric field
91
G. Jonsson
Experimental track widths of low
energy heavy ions in nuclear emulsion
95
R. Katz
A.S.-F. Li
Y-L. Chang
R.L. Rosman
E.V. Benton
Tracks of argon ions in IIford K-series
nuclear emulsions
101
R. Katz
Track measurements vs. track theory
in emulsion
111
C.S. Bogomolov
I.F. Razorenova
I.A. Ruditskaya
Structure of light nuclei tracks
117
C.S. Bogomolov
I.F. Razorenova
I.A. Ruditskaya
Cryogen-sensitive nuclear emulsions for
neutrino experiment
127
V.A. Ditlov
Theory of spatial calculation of primary
action of s-electrons in track
detectors with account of multiple
scattering
131
Track formation in nuclear emulsion
143
A.B.
V.G.
V.E.
N.Y.
L.V.
Y.V.
Akopova
Ambartsumyan
Dudkin
Magradze
Melkumyan
Potapov
M. Jensen
vii
Contents
Th. Wendnagel
E. Schopper
F. Granzer
Properties and technology of Ag CIdetectors
2. Experiments and technological
performance
147
SESSION 2.2: GLASSES AND MINERALS
Chairman: V. Perelygin
B. Bertel
T.D. Mark
M. Pahl
Investigation of the annealing behaviour
of fission track damage in apatite by
absorption spectroscopy
159
K.L.
J.S.
V.P.
A.P.
Development of a better etchant for
soda glass nuclear track detector
165
J.H. Roberts
R. Gold
F.H. Ruddy
Thermal annealing studies in muscovite
and in quartz
177
N. Segovia
R. Herrera
Latent track annealing in glass: A
comparison of thermal and gamma induced
annealing
191
J.S.
V.P.
K.L.
A.P.
Enviornmental effects on fission fragmen
tracks in soda glass nuclear track
detectors
199
The determination of fission fragment
energy deposition by means of SSNTdetectors
211
J.H. Adams
A precision etching bath for plastic
track detectors
223
W. Arndt
W. Enge
Temperature and storage dependence of
registration properties of cellulose
nitrate plastic detectors
233
P.H. Fowler
S. Amin
V.M. Clapham
D.L. Henshaw
Track recording properties of the
plastic CR-39 for non-relativisttc
ions in the charge range 6>Z>29
239
S.R. Hashemi-Nezhad
P.F. Green
S.A. Durrani
Effect of etchant normality on the
response of CA 80-15 cellulose nitrate
to heavy ions
245
Gomber
Yadav
Singh
Sharma
Yadav
Singh
Gomber
Sharma
H. Hirshfeld
N.H. Shafrir
SESSION 2.3: POLYMERS
Chairman: E. Benton
Contents
viii
G. Siegmon
B. Lemmert
W. Enge
Thermal fading of latent tracks of iron
nuclei in lexan polycarbonate
251
G. Somogyi
Gy. Alma si
Etch pit formation in thin foils and
a conductometric study of hole
parameters
257
G.
M.
N.
J.
Somogyi
Toth-Szilagyi
Monnin
Gourcy
Non-etching track visulation: some
recent results
267
F.
W.
P.
E.
A.
Steinhausler
Hofmann
Pfligersdorffer
Pohl
Auinger
Study of track ultra-structure for
high LET particles under varying
environmental conditions
277
A study of the registration properties
of polyethylene-terephthalate
283
S.P. Tretyakova
P.Y. Apel
L.V. Jolos
T. Mamonova
V.N. Shirkova
T.A.
W.K.
E.V.
R.M.
C.S.
Gruhn
Li
Benton
Cassou
Johnson
Etching mechanism and behaviour of
polycarbonates in hydroxide solution:
lexan and CR-39
291
C.S.
E.V.
R.M.
R.P.
D.J.
Johnson
Benton
Cassou
Henke
Hi ldebrand
A study of the critical dip angle for
track registration in plastic track
detectors
303
Non-etching track visualization:
developments of the method
311
Etch induction time in solid state
nuclear track detectors
315
M.
J.
G.
M.
Monnin
Gourcy
Somogyi
Toth-Szilagyi
A.L. Maurya
S.K. Bose
S.K. Tuli
SESSION 2.4: ELECTROCHEMICAL ETCHING
Chairman: L. Medveczky
S.A.R. Al-Najjar
R.K. Bull
S.A. Durrani
Some chemical and electrochemical
etching properties of CR-39 plastic
323
G. Hassib
E. Piesch
G. Massera
Electrochemical etching of alpha
particles in polycarbonates and
applications
329
Contents
ix
P. Le Thanh
P. Nikpay
Un dispositif de ComptageT a discharges
disruptives permettant d Attenuer les
decharges disruptives multiples
337
M. Najzer
R. IIic
I. Remec
Enhancement of track-etch image by the
sparkling technique
363
G. Somogyi
G. Dajko
A proposal for spark counting at high
track densities
371
G.
G.
K.
F.
Somogyi
Dajko
Turek
Spurny
On the background and recoil tracks in
electrochemically etched PC and PET
detectors
381
G.M. Hassib
E. Piesch
G.E. Massera
A wide energy range neutron dosimeter
using electrochemical track etch
detectors
389
U. Lotz
E. Pitt
A. Scharmann
Electrochemically etched cellulose
nitrate films as fast neutron
dosimeters
403
L. Tommasino
G. Zapparoli
R.V. Griffith
Electrochemical etching-I Mechanisms
413
L. Tommasino
G. Zapparoli
R.V. Griffith
A. Mattei
Electrochemically etching—II Methods,
apparatus, results
425
SESSION
2.5: PROTON RECORDING POLYMERS
Chairman: H.G. Paretzke
P.H. Fowler
V. Chapham
D.L. Henshaw
D. O'Sullivan
A. Thompson
The effect of temperature-time cycles
in the polymerisation of CR-39 on the
unformity of track response
437
G. Somogyi
I. Hunyadi
Etching properties of the CR-39
polymeric nuclear track detector
443
A. Thompson
D. O'Sullivan
C. O'Ceallaigh
Development studies of CR-39 for
cosmic ray work
453
E.Y. Benton
C.C. Preston
F.H. Ruddy
R. Gold
J.M. Roberts
Proton and alpha particle response
characteristics of CR-39 polymer for
reactor and dosimetry applications
459
S.S.N.T.D. A"
Contents
X
E.V.
A.L.
R.A.
R.V.
Benton
Frank
Oswald
Wheeler
Proton recording neutron dosimeter for
personnel monitoring
469
SESSION 2.6: DETECTORS MEASUREMENT
Chairman: H.G. Paretzke
R.
Z.
A.
D.
Antan^sijevic
Todorovic
Stamatovic
Miocinovic
Semiautomatic track scanning in solid
state nuclear track detectors
479
P. Campbell
A.J. Orr
Quantitative evaluation of particle
track detectors
433
J. Dutrannois
A.H. Sullivan
Hole counting in track etch foils using
an image-analysing computer
497
J. Palfalvi
I. Eordogh
B. Vero
Track density measurements using a
VIDIMET-II A type image analyser
503
R.P. Henke
E.V. Benton
R.M. Cassou
A method of automated HZE-particle
Z-spectra measurement in plastic
509
SESSION 3: FIELDS OF APPLICATION
SESSION 3.1: NEUTRON DOSIMETRY
Chairman: J.W.N. Tuyn
Detection of delayed neutrons in a
nuclear reactor using the solid state
track etch technique
521
J. Dutrannois
M. Hofert
A.H. Sullivan
J.W.N. Tuyn
A personal neutron monitoring system
based on solid state nuclear track
detectors
527
R. Gold
F.H. Ruddy
J.H. Roberts
Applications of solid state track
recorders in United States nuclear
reactor energy programs
533
A.U. Haque
C.B. Besant
B.W. Hooton
Solid state nuclear track detectors
in reactor physics problems
549
M.A. Kenawy
A.M. Sayed
Comparison of various types of SSNTD
for neutron dosimetry
559
H. Boeck
Contents
H.A. Khan
K. Nadeem
R.A. Akber
The gamma dose measurements in the
spent fuel elements of a power reactor
L. Medveczky
Comparison of the Neutron sensitivity of
SSNTDs
Neutron dosimetry with a proton
sensitive cellulose nitrate
F. Spurny
K. Turek
H.B. Luck
A. Danis
M. Oncescu
xi
573
581
585
High neutron fluence measurement
using simultaneously the mica muscovite
both as track detector and as material
with low uranium content
591
F. Abu-Jarad
J.H. Fremlin
Track etch detectors for radon measurements inside houses and for building
material
599
P. Duport
G. Madelaine
P. Zettwoog
J.F. Pineau
Enregistrement des rayonnements alpha
dans le dosimetre individuel et le^
dosimetre de site du commissariat a
1'energie atomique
609
D. Duport
A.M. Chapuis
J.F. Pineau
Six mois d experience en dosimetrie
individuelle des descendants du
radon dans une mine d'uranium
617
H.A. Khan
R.A. Akber
K. Nadeem
Some latest developments in the
application of alpha sensitive plastic
films for uranium exploration
623
A. Mouden
A. Renoux
G. Madelaine
Etude
experimentale du comportement
!
d un dosimetre a T vis-a-vis de
certains types d aerosols
633
M. Nicolae
A. Dragu
Critical view on solid state nuclear
track detector application in
dosimetry
639
SESSION 3.2: ALPHA DOSIMETRY
Chairman: J.H. Roberts
f
SESSION 3.3: ALPHA AUTORADIOGRAPHY
Chairman: J.H. Roberts
D.L. Henshaw
A.P. Fews
D.J. Webster
The rnicrodistricution of a active
nuclei in bronchial tissue by
autoradiography using CR-39
649
R. Ilic
M. Najzer
A. Podgornik
The resolving power of autoradiography
with solid state nuclear track
detectors
655
Contents
xii
L. Medveczky
L. Bozoky
Leakage testing of medical radium sources
667
J. Vukovic
R. Antanasi jevic
Alpharadioautohistography by polymer
nuclear track detector
673
SESSION 3 . 4 : NEUTRON AUTORADIOGRAPHY
Chairman: M.A. Kenawy
K. W. Bentley
J.H. Wyatt
D.J. Wilson
Biological applications of neutron- 2 39
induced autoradiography
of plutonium
2 35
and uranium
681
R.
v
f i.
M.
A.
Heavy charged particle autoradiography
using Kodak maximum resolution plate
689
Two techniques using Makrofol KG
for measurement of uranium low
concentrations
695
Uranium trace analysis of some materials
using solid state nuclear track
detectors
701
II ic
Humar
Najzer
Podgornik
L.P.
E.M.
M.F.
O.Y.
Geraldo
Tanaka
Cesar
Mafra
S.K. Chakarvarti
N. Lai
K.K. Nagpaul
SESSION 3 . 5 : CHARGED PARTICLE RADIOGRAPHY AND NEUTROGRAPHY
B.E. Fischer
B. Genswurger
R. Spohr
Density mapping of microbjects and
micromachining of surfaces by means
of heavy ion lithography
719
E.V. Benton
R.R. Henke
C.A. Tobias
W.R. Holley
J. Fabrikant
Charged-particle radiography
725
G. Rimpl
B. Uebigau
Cellulose nitrate foils for
qualitative and quantitative measurements in biological dosimetry
733
K. Thiel
H. Kulzer
W. Herr
Charged particle tracks as a means
to measure sputter yield angular
distribution in 2ir-geometry
739
xiii
Contents
SESSION 3.6: NUCLEAR FUSION
E.V. Benton
N.M. Ceglio
Diagonsis of high-density implosions
of laser fusion targets using highsensitivity nuclear track detectors
747
N.M. Ceglio
E.V. Benton
Imaging thermonuclear burn using solid
state track detectors
755
SESSION 3.7: PROSPECTION OF RADIOACTIVE AND FISSIONABLE MINERALS
Chairman: K. Thiel
f
Quelques exemples d application des
detecteurs sol! ides de particules
atomiques a l etude des minerals
d'uranium
765
R. Coppens
M. Richard
P. Richard
Utilisation comparees des emulsions
photographiques nucleaires et des
films
T
de nitrate de cellulose dans l etude des
rayons a en geologie et mineralogie
771
G. Espinosa
A. Moreno
Alpha detection by SSNTD's
111
I.Y. Khadduri
On the use of cellulose nitrate film
for uranium exploration
785
A.E. Liehu
Fission track radiography of uranium
801
Z.
R.
B.
J.
D.
Fission track annealing of orpiment
805
On the necessity to standardize the
sample preparation in fissionable
element content measurement by the
fission track method
811
On the fissionable element infiltration
and retention in soils
815
F. Chantret
Todorovic
Antanasijevic
Jakupi
Vukovic
Miocinovic
A. Danis
A. Danis
M. Oncescu
C. Negrescu
SESSION 3.8: POROSITY AND MICROFILTERS
Chairman: K. Thiel
C. Riedel
R. Spohr
Areal dispersions of etched nuclear
tracks and their consequences for
nuclear track filters
821
xiv
G.
P.
D.
R.
B.
R.
Contents
Tress
Vater
Hirdes
Brandt
Genswurger
Spohr
Some properties of nuclear track
microfiIters in mica
827
SESSION 3.9: HIGH AND LOW ENERGY NUCLEAR REACTIONS
Chairman: R. Katz
3
4
M. Balcazar-Garcia
S.A. Durrani
Isotopic separation of He and He in a
mixed radiation field
841
G. Baroni
Detection and lifetime of charmed
particles by a hybrid emulsion-bubble
chamber-counter set up
849
Detection of reaction fragments in
cellulose nitrate produced by fast
nucleons
851
D. Hildebrand
E.V. Benton
R.P. Henke
W. Heinrich
Fragmentation of high energy argon ions
in water
855
A.A. Marin
Heavy ion reactions at relativistic
energies
861
K.
W.
R.
K.
Grabisch
Enge
Beaujean
Fukui
A.
R.
E.
C.
J.
R.
H.
Ruiz
Niembro
Villar
Jacquot
Suren
Schmitt
Schweickert
Procedure experimentale en vue de la
determination des moments des particules
emises^dans les interactions protonnoyau a tres haute energie
869
A.
R.
E.
C.
J.
R.
H.
Ruiz
Niembro
Villar
Jacquot
Suren
Schmitt
Schweickert
Experimental device to measure the
moments of emitted particles in
hadron-nucleus interactions at very
high energies
875
M. Varnagy
J. Szabo
Z.T. Body
Application of a cellulose nitrate
detector for the simultaneous
study
7
6
of ^ ( d ^ a ^ H e and Li(d,p) Li
reactions
881
P. Chaudhry
A.U. Bajwa
A charged particle range-spectrometer
using solid state nuclear track
detectors
885
Contents
A. Waheed
Sigma hyperon emission in 1.5 GeV/c K"
meson interaction in light emulsion
nuclei (C5N,0)
xv
889
SESSION 3.10: FISSION AND VERY HEAVY IONS REACTIONS
Chairman: R. Katz
B. Grabez
Z. Todorovi£
R. Antanasijevic
The interaction of 300 MeV Ar ions with
uranium studied by the use of a plastic
track detector
899
N.A. Khan
H.A. Khan
K. Gul
R.A. Akber
M. Anwar
A. Waheed
G. Hussain
M.S. Shaikh
A new approach to measure reaction
parameters in the 14.8 MeV neutron
induced fission of Pu-240 and Pu-241
905
H.A. Khan
P. Vater
R. Brandt
Multiprong fission
events produced
2 0 8
by 1477 MeV P b ions in natural
uranium
915
A. Sicre
F. Caitucoli
G. Barreau
T. Benfoughal
B. Bruneau
T.P. Doan
B. Deroux
Mesure des distributions angulaires
des fragments de fission au moyen
detecteurs plastiques de traces
921
M. Debeauvais
S. Jokic
J. Tripier
Etude a I'aide du makrofol des
interactions U sur U et Pb a des
energies superieures a 7 MeV/UMA
927
R. Haag
G. Fiedler
T. Rautenberg
P.A. Gottschalk
G. Grawert
Coincidence measurements of heavy ion
reaction products via solid state
933
D. Lhagvasuren
V.P. Perelygin
S.G. Stetsenko
Kh. Murtazaev
The use of dielectric detectors in
search and identification of the
tracks of fragments from the spontaneous
fission of superheavy nuclei
939
A.U. Bajwa
P. Chaudhry
R.A. Akber
An attempt of finding the range distribution among fission fragments from
californium -252 s.f. using solid state
949
xvi
Contents
SESSION 3.11: DATING
Chairman: H.A. Khan
E. Bertel
T.D. Mark
M. Pahl
The interpretation of fission track
annealing behaviour in apatite and
other minerals
957
J.
D.
A.
G.
Fission track geochronology of the
hercynian platform in France
961
G. Poupeau
J. Carpena
A. Chambaudet
Ph. Romary
Fission track plateau age dating
965
P.F. Green
H.J. Mi 11 edge
M.J. Mendelssohn
E. Nave
P. Woods
Fission-track studies in diamond and
kimberlite
973
N. Lai
K.K. Nagpaul
K.K. Sharma
Applications of solid state nuclear
track detectors for the study of
cooling and uplift rate of Indian
subcontinent
979
S.A. Durrani
R.K. Bull
P. Mold
Fission-track record of meteorites:
Some recent results
991
D. Lhagvasuren
0. Otgonsuren
V.P. Perelygin
S.G. Stetsenko
B. Jakupi
P. Pellas
C. Perron
A technique for partial annealing of
tracks in olivine to determine the'
relative abundances of galactic cosmic
ray nuclei within Z^50
997
P.F. Green
R.K. Bull
S.A. Durrani
Etch rates of heavy ion tracks in
minerals
Carpena
Chaillou
Chambaudet
Poupeau
SESSION 3.12: METEORITES
Chairman: H.A. Khan
1003
Contents
xvii
SESSION 3.13: COSMIC RAYS AND RELATIVISTIC IONS
Chairman: M.M. Monnin
J.H. Adams
M.M. Shapiro
R. Silberberg
C.H. Tsao
The "Heavy Ions in Space" experiment
1011
R. Filz
Y.V. Rao
A. Davis
An experiment for measuring heavy cosmic
ray spectra
1021
W. Hunger
G. Siegmon
W. Enge
R. Beaujean
W.R. Webber
J.H. Chappell
J.C. Kish
Time resolving plastic detector
technique for the measurement of heavy
cosmic ray isotopes
1027
D. O'Sullivan
A. Thompson
J. Daly
C O'Ceallaigh
V. Domingo
A. Smit
K.-P. Wenzel
A solid state track detector array
for the study of ultra heavy cosmic
ray nuclei in earth orbit
1033
M.
A.
F.
C.
M.
M.
J.
J.
A charge and mass discrimination
method in lexan polycarbonate
1041
R. Pfohl
C. Jacquot
J.N. Suren
C. Heilmann
Utilisation des emulsions dans des
experiences de dosimetrie et de reperage
d'ions lourds lors de vols de
Spacelab (NASA) 1981
1047
M. Schafer
R. Facius
H. Biicker
Response of bacillus subtil is spores to
heavy ion irradiation using cellulose
nitrate dectectors
1055
R.
W.
R.
S.
K.
K.
Scherzer
Enge
Beaujean
Hertzman
Kristiansson
SoderstrSm
Measurements of cosmic ray iron isotopes
in an emulsion-plastic detector
1063
G.
G.
W.
R.
Sermund
Siegmon
Enge
Beaujean
Registration properties of plastic
detectors for quasi-relativistic Fe ions
1071
Ortega
Vidal-Quadras
Fernandez
Baixeras
Casas
Gonzalo
Medina
Sequeiros
xviii
B.
R.
H.
W.
Sojka
Scherzer
Rohrs
Enge
Contents
Single sheet particle identification
in cellulose nitrate plastic
1079
Author Index
1085
Subject Index
1089
LIST OF PARTICIPANTS
Australia
Czechoslovakia
W.R. Ellis Roy
Australian Atomic Energy Commission
Sutherland NSW
F. Spurny
Laboratory for Radiological Dosimetry
Czechoslovak Academy of Sciences
Na Truhlarce 39/2a
18086 Praha 8
Austria
J. Trousil
Inst, for Research
6, Veclavkova
16625 - Praha
E. Bertagnoli
Inst, fur Exp. Physics
6020 - Innsbruck
E. Bertel
Inst, fiir Physi. Chemie
6020 - Innsbruck
Egypt
G.M. Hassib
Atomic Energy Establishment
Cairo
H. Boeck
Atominstitut
Schuettelstrasse 115
1020 - Vienne
M.A. Kenawy
University College for Girls
Ain Schams University
Helliopolis
Cai ro
W. Hofmann
Inst, of Biophysik
Akademiestrasse 26
5020 - Salzburg
Brasil
Fed. Rep. Germany
H.G. Baumgardt
Inst, fiir Kernphysik
August Euler-Strasse 6
6000 Frankfurt 90
L.P. Geraldo
Instituto de Energia Atomica, I.E.A.
Area de Fisica Nuclear C P . 11049
Pinheiros, Sao Paulo
R. Beaujean
Institut fiir Reine und Angewandte
Kernphysik
Universitat Kiel
Olshausenstr. 40/60
2300 - Kiel
Canada
P. Campbell
Atomic Energy of Canada Limited
Whiteshell Nuclear Res.
Pinawa, Manitoba, Roe IIo
xix
XX
List of Participants
W. Enge
Institut fur Reine und Angewandte
Kernphysik
Universitat Kiel
Olshausenstr. 40/60
2300 - Kiel
F. Granzer
Institut fur Angewandte Physik
Abt. fur Wissenschaftl. Photographie
Robert-Mayer-Str. 2
6000 - Frankfurt 1
E. Pitt
I. Physikal. Institut
Justus-Liebig Universitat
Heinrich Buff Ring 16
6300 - Giessen
G. Rimpl
Inst, ftir Biologie - GSF
Ingolstadter Landstrasse
8042 - Neuherberg
K.0. Groeneveld
Inst, fur Kernphysik der Universitat
6000 - Frankfurt am Main
E. Schopper
Institut fiir Kernphysik
Universitat Frankfurt
August-Euler-str. 6
6000 - Frankfurt 90
R. Haag
II. Physical. Institut
Universitat Giessen
Arndtstr. 2
6300 - Giessen
J.U. Schott
Institut fur Kernphysik
August-Euler-str. 6
6000 - Frankfurt 90
W. Heinrich
Gesamthochschul e Siegen
Fachbereich Physik
Hoelderlinstr. 3
5900 Siegen 21
Sermund
Institut fiir Reine und Angewandte
Kernphysi k
Universitat Kiel
Olshausenstr. 40/60
2300 - Kiel
Hunger
Kernphysik
Universitat Kiel
Olshausenstr. 40/60
2300 - Kiel
0. Kowarik
Tech. Univ. Inst, fur Radioch.
Munich
U. Lotz
1. Physikal. Institut
Justus-Liebig Universitat
Heinrich Buff Ring 16
6300 - Giessen
G. Siegmon
Kernphysik
Universitat Kiel
Olshausenstr. 40/60
2300 - Kiel
R. Spohr
Gesellschaft fur Schwerionenforschung
6100 - Darmstadt
K. Thiel
Institut fiir Kernchemie
der Universitat
Zulpicherstr. 47
5000 - Koln 1
E. Obst
Institut fur Kernphysik
August Eulerstr. 6
6000 - Frankfurt 90
B. Uebigau
Institut fiir Biologie - GSF
Ingolstadter Landstr. 1
8P42 - Neuherberg
H.G. Paretzke
Institut fur Strahlenschutz der GSF
Ingolstadter Landstr. 1
8042 - Neuherberg
P. Vater
Phillips Universitat
Kernchemie FB 14
Lahnberge
3550 - Marburg/Lahn
T. Wendnagel
Institut fiir Kernphysik
August Euler-Str. 6
6000 - Frankfurt 90
Finland
A. Liehu
Reactor Laboratory
Technical Research Centre of Finland
Rakentajanaukio 2
02150 - Espoo 15
France
XXi
P. Duport
STEPAM - C.E.A.
B.P. 1
87640 - Razes
J. Fain
Laboratoire de Physique Corpusculaire
Universite de Clermont II
B.P. 45
63170 - Aubieres
M. Fantini
Kodak - Pathe
Centre de Recherches
30, Rue des Vignerons
94300 - Vincennes
C. Amalric
C.E.A. 1
Centre d Etudes Nucleaires
91680 - Bruyeres-Le-Chatel
H. Franqois
C.E.A.
Centre d'Etudes Nucleaires
B.P. 6
92260 - Fontenay-Aux-Roses
F. Bermann
C.E.A.
B.P. 6
G. Gasset
Laboratoire de Biologie Medicale
Faculte de Medecine
37, Allees Jules Guesde
31400 - Toulouse
D. Chaillou
Labo. C.E.A.-C.N.R.S.
Centre des Faibles Radioactivites
91190 - Gif-Sur-Yvette
R. Gaulard
E.D.F.
I, Avenue du General De Gaulle
92140 - Clamart
A. Chambaudet
Laboratoire de Chi mie-Physique
Bat. 350 - Avenue Jean Perrin
91405 - Orsay
C. Heilmann
Centre de Recherches Nucleaires (SADVI)
67037 - Strasbourg Cedex
F. Chantret
Cogema - D.R.M.E.
Service Mineralogie
B.P. 99
92320 - Chatillon
A.M. Chapuis
C.E.A.
B.P. 6
M. Debeauvais
Centre de Recherches Nucleaires (SADVI)
M. Jung
Centre de Recherches Nucleaires (PNHE)
N. Kurtz
Centre de Recherches Nucleaires (CBH)
J. Laverlochere
C.E.A. 1
Centre d Etudes Nucleaires 85 X
38041 - Grenoble
A. Lecart
Kodak-Pathe
8-26, Rue Villot
75580 - Paris Cedex 12
xxii
P. Le Thanh
C.E.A. - Sac1ay
Service Protection Rayon
A. Renoux
Faculte des Sciences
6, Avenue Le Gorgeu
29283 - Brest Cedex
J. P. t'lassue
t~.
Ri chard
Secretariat of the Committee on Science E.N.S.G.
and Techno logy
B.P. 452
Council of Europe
54001 - Nancy Cedex
R. Schmi tt
UER de Physique
R. Medioni
Laboratoire des Rayonnements Cosmiques
C.E.A. - DPR/STEP/STID
Centre dlEtudes Nuc1eaires
Universite Lyon 1
43, Bld du 11 Novembre 1918
B.P. 6
69621 - Vi11eurbanne
G. '·1eyer
Labora toi re Pi erre Sue
C.E.N. - Sac1ay
B.P. 2
J . P. r,'lo 1i to n
Lab. Rad. Ionisantes
123, Rue Albert Thomas
87060 - Limoges Cedex
Monni n
C.N.R.S.
Laboratoire de Physique Corpuscu1aire
24, Avenue des Landais B.P. 45
63130 - Aubieres
t~.
A. r/louden
Facu1te des Sciences
6, Avenue Le Gorgeu
29283 - Brest Cedex
J.F. Pineau
.s TEPAt·1 - C. E.A.
B.P. 1
87640 - Razes
H. P1 ane1
Labora toi re de Bi 01 ogi e r,1edi ca1e
Faculte de Medecine
37, A11ees Jules Guesde
31400 - Toulouse
G. Poupeau
Labo C.E.A. - C.N.R.S.
Centre des Faib1es Radioactivites
A. Serbat
E.T.C.A.
Servi ce DPN/VD
94114 - Arcue;l Cedex
R. Tabarde1
COGEMA - Etab. de Marcou1e
B.P. 170
30200 - Bagno1s-Sur-Ceze
J.L. Teyssier
Lab. Rad. Ionisantes
123, Rue Albert Thomas
87060 - Limoges Cedex
J. Tripier
Centre de Recherches Nucleai res (SADVI)
Hungary
I. Gerzson
P.E.C.S.
39-ES Dandas UT l/A 7633
L. Nedveczky
Institute of Nuclear Research
of the Hungarian Academy of Science
POB 51
4001 - Debrecen
J. Pa1fa1vi
Central Research Institute for Physics
Health Research Physics Dept
P.O.B. 49
1525 - Budapest
xxi i i
G. Somogyi
Italy
Institute of Nuclear Research of the
Hungarian Acaderny of Sciences
G. Baroni
POB 51
Univ. Roma
4001 - Debrecen
Piazzale delle Scienze 5
Roma
M. Varnagy
V. Carbonaro
Inst, of Exp. Physics
Viale Regina Margherita
Kossuth University - POB 10
00198 - Roma
4001 - Debrecen 1
India
N. Lai
Department of Physics
Kurukshetra University
Kurukshetra 132119
K.K. Nagpaul
Kurukshetra 123119
A. Sharma
Kurukshetra 132119
K.K. Sharma
Wadia Institute of Himalayan Geology
Dehradun
Iraq
I.Y. Khadduri
Reactor Department
Nuclear Research Institute
P.O. Box 765
Bagdad
Ireland
D. O'Sullivan
Dublin Institute for Advanced Studies
5, Merron Square
Dublin 2
A. Thompson
Dublin Institute for Advanced Studies
5, Merron Square
Dublin 2
L. Tommasino
Comitato Nazionale per l'Energia
Nucleare
Laboratorio Dosimetria e Biofisica CNEN
POB 2400
00100 - Roma-Casaccia
Korea
C O . Kim
Seoul 132
Mexico
M. Balcazar-Garcia
Centro Nuclear
Inst. Nat. de Investigaciones
Av. Insurgentes
SUR 1079 - Mexico 18 D.F.
G. Espinosa
Apartado Postal 20-364
Mexico 20, D.F.
N. Segovia
Tecualiapan 36
Mexico 21, D.F.
Nether! ands
G. Lautenbach
Netherlands Energy Research Foundation
ECN - P.O. Box 1
1755Z - Petten
xxiv
Pakistan
H.A. Khan
Nuclear Engineering Division
Pakistan Institute of Nuclear
Science and Technology
P.O. Nilore
Rawalpindi
C. Parvez
Nuclear Research Lab.
Govt College
Church Road
Lahore
Romania
M. Nicolae
Inst. Phys. et Ing. Nuc.
B.P. 5206
Bucarest
Spain
C. Baixeras
Departamento de Fisica Fundamental
Univ. Aut. Barcelona
Bellaterra
Barcelona
F. Fernandez-Moreno
Bellaterra
Barcelona
J. Medina
Grupo de Radiacion Cosmica
Comision Nacional de Investigacion
del Espacio
Madrid
A. Ruiz
Facultad de Ciencias
Univ. Santander
Santander
A. Vidal Quadras Roca
Bellaterra
Barcelona
Sweden
M. Jensen
National Institute of Radiation
Protection
Box 60204
10401 - Stockholm
G. Jonsson
Lunds Universytet
Solvegatan 14
223-62 - Lund
Switzerland
Hofert C.E.R.N.
1211 - Geneve 23
A. Sullivan
H.S. Div. - C.E.R.N.
1211 - Geneve 23
J.W.N. Tuyn
C.E.R.N.
1211 - Geneve 23
G. Vanderhaege
Div. P.E. - C.E.R.N.
1211 - Geneve 23
United Kingdom
F. Abu Jarad
Physics Department
Birmingham University
Birmingham B 1 5 2TT
S. Al-Najjar
P.O. Box 363
Bi rmin gharri
V.M. Clapham
H.H. Wills Phys. Lab.
University of Bristol
Tyndall Avenue
Bristol
G. Dixon
Imperial College
London SW7 2BX
S. Durrani
Birmingham B15 2TT
P.F. Green
Dept of Geology
University College London
Cower Street
London WC IE 6BT
A. Haque
Dpt Mech. Eng.
Imperial College
London SW7 2AZ
Hashemi-Nezhad S. Reza
Dept of Physics
P.O. Box 363
Birmingham
P. Henderson
Dept of Mineralogy
British Museum
Cromwell Road
London SW7 5BD
D.L. Henshaw
H.H. Wills Phys. Lab.
Univ. Bristol
Tyndall Avenue
Bristol
R. Longden-Thurgood
Vicisers Shipbuilding Group Limited
Naval Research Dept
P.O. Box 6
Barrow in Furness, Cumbria
J. Miles
NRPB, Harwell
Didcot, Oxon
A.J. Mill
Berkeley Nucl. Laboratory
Glos. GL13 9PB
I. Rogers
The Polytechnic of North London
Holloway
London, N7 8DB
R.H. Taber
IIford Limited
Christopher Martin Road
Basildon, Essex
U.S.A.
J.J. Adams
Code 7022, Naval Research Labor
D.C. 20375
Washington
E. Benton
Physics Department
Univ. San Francisco
San Francisco, California 94117
N. Ceglio
c/o L-479
Lawrence Livermore Univ.
Livermore, CA 94550
R. Katz
364 Behlen Laboratory
Nebraska University
Lincoln, Nebraska 68508
J.H. Roberts
Physics Department
Mai caster Col lege
St Paul, MN 55105
R.V. Wheeler
R.S. Landauer, Jr. & Co
Science Road
Glenwood, IL. 60425
U.S.S.R.
Akopova
State Inst, of Photochem. Ind.
Leningradsky Prospect
Moscow
V. Andreanov
Moscow
C. Bogomolov
Moscow
V. Ditlov
Institute of Chemistry of Ministry
of Chemical Industry
Kirova str. 20
Mo scow
XXV
xxv i
List of Particpants
Egorov
Inst. Theor. Exp. Phys.
Moscow
V. Perelygin
J.I.N.R.
Head Post Office
P.O. Box 79
Moscow
I. Razorenova
Moscow
Yugoslavia
B. Grabez
Institute of Physics
Studentski trg 12 ; POB 57
11001 Belgrade
R. Ilic
J. Stefan Inst.
P.O.B. 199
61001 - Ljubljana
S. Jokic
Institute of Physics
Studentski trg 12 ; POB 57
11001 - Belgrade
A. Podgornik
P.B. 431
61001 - Ljubljana
J. Vukovic
Inst. Biophysique
Facul te de Me de cine
Visegradska 26/2
11001 - Belgrade
Israel
H. Hirshfeld
Department of Nuclear Engineering
Technion - Israel Institute of
Technology
32000 - Haifa
N.H. Shafrir
Department of Nuclear Engineering
Technion - Israel Institute of
Technology
32000 - Haifa
OPENING SESSION
Opening by the Vice-Chancellor of the Universities of Lyon
Statements by: Prof. R. Schmitt, President of the International
Conference
Prof. E. Schopper, Frankfurt University
Dr. J.P. Massue, Council of Europe
Prof. (J. Bogomolov, Moscow
1
M . le Recteur GUYARD, Chancelier
des Universites de Lyon, apres avoir r e m e r c i e le
Professeur SCHMITT et les organisateurs lyonnais,
souhaite la bienvenue aux congressistes, se rejouit tout
particulierement, comme ancien recteur de Strasbourg,
de la participation du Conseil de l'Europe et declare
ouvert le X e congres dont il sera heureux d'accueillir
les m e m b r e s a. la Chancellerie en fin de journee.
2
Monsieur
le Recteur,
Chancelier
Monsieur
le President
Monsieur
le Vice-President
des Universites
de 1'Universite
Claude
de 1'Universite
de
Lyon,
Bernard,
Claude
Bernard,
En tant que President
de ce Congres, et en mon nom propre, je tiens
en premier lieu, Messieurs,
a vous remercier
d'avoir bien voulu assister a cette
seance inaugurale,
rehaussant par votre presence,
le prestige
du
Congres.
Mesdames,
Messieurs,
Chers
Collegues,
Aujourd'hui
s'ouvre le lOe Congres International
sur les
Detecteurs
Solides de Traces Nucleaires
: Vingt deux ans se sont deja ecoules depuis la
creation, au Laboratoire
de Physique Corpusculaire
de Strasbourg,
du ler
Congres
de Photographie
Corpusculaire,
qui est a 1 'origine de ces reunions sur les
Detecteurs
Solides.
Les sujets d'etude des premiers
Congres : STRASBOURG
(1957),
MONTREAL
(1958), MOSCOU
(1960), MUNICH (1962) et le C.E.R.N, a GENEVE
(1964)
se limitaient
a 1 'emulsion ionographique,
unique detecteur
solide
enregistrant
des traces de particules
nucleaires
connu a 1 'epoque.
Mais apres une table ronde Internationale
a STRASBOURG
(1963),
suivie d'un Congres International
a CLERMONT-FERRAND
(1969) traitant de nouveaux
detecteurs
solides non photographiques,
les Congres ulterieurs
: FLORENCE
(1966),
BARCELONE
(1970), BUCAREST
(1972) et MUNICH-NEUHERBERG
(1976) ont englobe
dans
leurs etudes 1 'ensemble des detecteurs
solides, c'est-a-dire,
en plus des
emulsions ionographiques,
les monocristaux
d'halogenures
d'argent,
les
polymeres
ou plastiques,
certains mineraux,
comme le mica, et certains
verres.
La periode enthousiaste
des premiers
Congres est peut-être
depassee,
mais depuis la technique des detecteurs
solides, toujours en voie
d'amelioration
reguliere,
leurs domaines d 'utilisation
se sont etendus et multiplies.
Ce sont
la les raisons qui justifient
amplement
1'existence
de ce genre de
Congres.
Il est vrai qu'a une certaine epoque, des augures avaient annonce la
disparition
de ces techniques
de
detection.
La liste des publications
proposees
a cette Conference,
du fait
notamment
de la diversite
des domaines scientifiques
abordes, est une reponse
contradictoire
flagrante
a ces
propheties.
3
4
R. Schmitt
Actuellement
encore, les detecteurs
solides sont utilises
dans
les recherches
fondamentales
de pointe. Je ne voudrais citer ici que deux
exemples
: Aupres des Grands Accelerateurs,
le C.E.R.N. a GENEVE, BATAVIA aux
U.S.A., on utilise les emulsions ionographiques
dans les montages
hybrides,
associant differents
types de detecteurs,
en vue de la detection
de la particule
"charmee", par exemple. Par ailleurs,
des grandes surfaces de detecteurs
solides,
allant jusqu'a quelques metres carres, exposees en ballon stratospherique
et en
satellite,
ont permis la mise en evidence d'evenements
tres rares du
rayonnement
cosmique, comme les ions tres lourds, dont la charge s'etend jusqu'a
1'Uranium,
et probablement
au-dela. Independamment
de ces utilisations
initiales dans la
recherche fondamentale
des detecteurs
solides, 1 'eventail de leurs
domaines
d'application
s'ouvre chaque jour de plus en plus. Citons :
- la dosimetrie
neutronique,
dans les reacteurs
et pour
a la fois pour la determination
la protection
du personnel
;
- la neutrographie
et la radiographie
aux ions
meme la radiographie
aux rayons X ;
lourds,
- 1'autoradiographie,
permettant
la localisation
milieu biologique
ou mineral avec une precision
de millimetre
;
- la prospection
miniere,
elements fissiles ;
du flux
completant
ou
neutronique
remplacant
du traceur incorpore dans un
pouvant atteindre
le millieme
en vue de la determination
de la concentration
en
- la simulation
des reactions de fusion, en vue de la mise au point de
reacteurs
thermonucleaires,
qui remplaceraient
avantageusement
les reacteurs
de fission :
- la radiodatation
archeologiques.
des roches
et des meteorites,
et meme
certaines
datations
Nous sommes tous conscients
des difficultes
de traiter, dans un
meme congres, des sujets aussi divers. Mais il m'a semble utile, que de temps
a autre, des specialistes
de domaines tres differents,
aient la
possibilite
d'evoquer, en commun, les theories sur les mecanismes
d'interactions
des
particules
ionisantes
avec le milieu solide traverse et les theories sur les
formations
des images latentes dans ces milieux. D'autre part, ils peuvent
fructueusement
confronter
leurs methodes de stabilisation
de 1 'image
latente,
de visualisation
des traces et de mesures des parametres
de ces traces.
Ainsi, il peut s'averer qu'une methode de mesure globale, mise au
point pour la dosimetrie,
puisse suggerer une idee de reperage de
1'evenement
rare du rayonnement
cosmique enregistre
dans un autre detecteur
solide.
Le succes de la Conference
dependra done essentiellement
des
orateurs,
dans la mesure oil ils tiendront compte du fait que 1 'auditoire est compose de
Chercheurs
axes sur des domaines de recherche
tres
differents.
Statements
5
Par ailleurs,
j 'ai le plaisir
de vous informer
que samedi
matin
se tiendra
une reunion
du Groupe de Travail
de Biophysique
Spatiale
de
l'Assemblee
Parlementaire
du Conseil
de l'Europe.
Ce Groupe est a
l'origine
de la participation
europeenne
au programme
de recherche
des sciences
de la
vie dans 1 'espace, par exemple,
lors des vols Apollo
et dans le cadre
du
programme
Apollo-Soyouz.
Une remarque
relative
aux Comptes-Rendus
du Congres.
11 nous a
semble logique
de soutenir
1'unique
Revue Internationale
"Nuclear
Track
Detection"
traitant
de nos detecteurs
solides
de traces nucleaires.
En depit de
1'effort
financier
demande,
qui represente
une large part des droits d'inscription,
nous
avons accepte
que cette Revue assure la publication
des Comptes-Rendus
de
notre
reunion.
Rendus
J'espere
que nous n'aurons
paraitront
dans un tout proche
remercier
Au nom
vivement
du Comite
:
pas a le regretter
avenir.
d'Organisation
du Congres,
et que
les
Comptes-
permettez-moi
de
- Monsieur
le Recteur,
pour le patronage
qu'il a bien voulu accorder
a ce
Congres,
et pour la reception
qu'il se propose
d'offrir
aux
Congressistes
a la
Chancellerie,
- Monsieur
le Prefet
pour les receptions
ici
presentes,
de Region
et Monsieur
le Maire de la Ville de LYON,
qu'ils ont prevues,
par ailleurs,
en faveur des
personnes
- l'Assemblee
Parlementaire
du Conseil
de l'Europe
pour le patronage
bien voulu conceder
a ce Congres
et pour son aide materielle
tres
durant la preparation
de ces
Journees,
qu'elle
a
efficace
- Le Centre National
de la Recherche
Scientifique
pour 1 ' interet
qu 'il a bien
voulu nous manifester
en cette circonstance
et pour sa contribution
financiere,
- Le Centre National
d'Etudes
et son aide
materielle,
Spatiales,
pour
le patronage
accorde
a ce
- Les Etablissements
KODAK-PATHE,
qui nous ont permis
1'organisation
"Soiree Beaujolaise",
grace a leur participation
financiere,
- Les Etablissements
ILFORD-LUMIERE,
pour
se proposent
d'offrir
aux Congressistes
de la
Photographie.
- Les Syndicats
d'Initiative
tion touristique
dont ils
d'une
les documents
iconographiques
au "Chateau
Lumiere",
devenu
des Villes de LYON
ont bien voulu nous
et STRASBOURG,
pour
faire
beneficier.
Congres
la
qu'ils
Musee
documenta*
6
R. Schmitt
Je tiens
a remercier
:
- Le President et le Vice-President
de notre Universite
accepter que le siege de notre Congres soit le Campus
- Le Directeur
de 1 'U.E.R. de Chimie,
notre disposition
cet AMphitheatre,
de la
Physique,
- Le Directeur
de l'U.E.R.
qui ont bien
Universitaire
voulu
de La
Doua,
qui a bien voulu consentir
a mettre a
mieux adapte pour ce Congres que celui
de Physique
Nucleaire,
pour
son
aide,
- Egalement,
le Directeur
de l'U.E.R. de Physique, pour les facilites
accordees
pour certains travaux de Secretariat
et notamment,
pour 1 'impression
des
resumes afferents
au Congres. Pour ce dernier travail, realise avec
diligence,
que Madame GAYARD veuille bien trouver ici 1 'expression de nos
meilleurs
remerciements.
Mais pour l'essentiel,
fin sans 1 'aide efficace apportee,
de
STRASBOURG.
ce Congres n'aurait pu etre mene a bonne
en permanence,
par le Conseil de 1 'Europe
J'exprime mes plus vifs remerciements
a 1'ensemble
du
personnel
qui a bien voulu se deplacer pour assurer efficacement
la bonne marche de
ces journees :
- Mme
S. PFISTER
- Melle M. COBUT
Strasbourg.
et Melle
V. PEREIRA
et Mme F. OHLMANN
du Conseil
du Centre
de 1 'Europe,
de Recherches
Nucleaires
de
Parallelement,
j 'adresse mes remerciements
a mes Collegues
du
Comite d'Organisation,
qui ont bien voulu prendre en charge, durant ce congres,
quelques taches ingrates.
Citons ici, Melle N. KURTZ, pour les droits
d'inscription et le logement des participants
; M. M. MONNIN, pour la
centralisation
des publications
et la liaison avec la Maison d 'Edition PERGAMON, pour
1'impression des Comptes-Rendus
de notre reunion. M. H. FRANCOIS supervisera
la bonne
marche des
seances.
En conclusion,
permettez-moi
Congressistes
de fructueuses
discussions
et un agreable sejour a LYON.
stay
in
I wish
LYON.
you fruitful
de souhaiter
scientifiques
discussions
during
a 1 'ensemble
lors de ces
the Conference
des
Journees
and a
pleasant
Allocution prononcee par Prof. Schopper a la seance
1
d ouverture, le lundi 2 juillet 1979.
Me s d am e s, Messieurs
Comme president de la conference precedente a Muenchen en
1976,
je suis heureux de dire quelques mots a l'occasion de
1
l ouverture de la conference presente, qui gr&ce a nos collfegues
frangais - le professeur Roger Schmitt, comme president et avec
l'aide du Secretaire de la Commission de la Science et de la
Technologie du Conseil de l'Europe, Br. Massue, pouvait §tre
organisee a Lyon. Je voudrais leur exprimer, aussi je pense, au
nom des participants, nos remerciements.
J'ai commence a parler dans la langue de Descartes et
dÂmpkre - hommage au pays et au lieu de la conference. Je vais
repeter dans un petit moment mes paroles dans la langue de
Shakespeare et de Newton, que nous sommes habitues d'appliquer dans
une version modifiee, aux conferences Internationales.
!
C est le dixieme de nos Congrfes Internationaux sur les
Detecteurs Solides de Traces Nucleaires, qui en 1957 ont commence
a Strasbourg, et qui ont ete continues toutes les deux ou trois
annees a plusieurs endroits en Europe et au Canada.
Je vous rappelle la grande epoque des emulsions nucleaires
pendant la sixifeme et la septieme decade de notre siecle.
Les congrks nous
avaient donne la facilite de discuter dans
f
un cercle limite d experts qui encltit de jeunes gens interesses a
la m^thode fascinante de la photographie corpusculaire.
Nous avons maintenu ces congres limites, qui nous ont men£s
dans une epoque de nouveaux detecteurs ~ des plastiques et des
dielectriques
en1 general, et je suis stir - des cristaux
1
d halogdnures d argent.
f
f
Compares
a l epoque des emulsions nos congres n ont point
f
perdu de l inter§t, ce qui se demontre par le grand nombre de
contributions scientifiques sur les applications et sur les
mechanismes fondamentaux.
Je suis convaincu que nos congres seront continues en depit
des developments competitives des methodes electroniques, ou
quelque part en cooperation avec eux.
f
Je souhaite a ce Congres a Lyon un1 grand succes et j attends
que nous tous retournerons, enrichis d informations nouvelles.
S.S.N.T.D.—B
7
8
E . Schopper
I am now switching to English:
I should say some words to the situation, as I see it:
There are certain domains of applications of SSNTD where they are
really unique, on account of their particular properties. First
of all, it is their high spatial resolution in a microscopic scale
down to fractions of a micron. As 4 ^ - detectors they are offering
full spatial information about complex events, for instance, in
high energy nuclear collisions where one observes "stars" with a
large number of prongs of fragments and new particles from the
interaction. Comparable electronic multiparameter experiments are
feasible with high energy and mass resolution, but with highly
expensive and complex layout.
We learned about radiographs with fast heavy ions which reflect
the mass distribution of macroscopic objects as three dimensional
profile of residual ranges of the ions in the volume of a detector
stack. They are accumulative and passive systems, capable of
recording and collecting also rare events over a long period of
time.
This opens many fields of their application in cosmology,
geology, prospecting and dosimetry; together with their spatial
resolution in autoradiography and radiobiological research too.
Time resolution is achievable - not comparable with that of
electronic devices, however - with triggerable silver-chloride
detectors or systems of moving detector layers. Finally, hybride
experiments with coupled electronic detectors and SSNTD have been
made in high energy physics and space research.
One of the essential disadvantages of SSNTD - existing at least
in the past - the low speed of evaluation, could be reduced by
electronic devices, video-electronic systems and data reduction
and handling. Further improvements are still necessary and
possible. Essential progress of the SSNTD technique will strongly
depend on improved methods of evaluation.
I think, I should neither go into more details about facts
which are known to the audience to a great deal, nor should I
anticipate what will be the topics and the aim of our present
conference.
It remains to me to wish the conference full success, and
enjoyable days in Lyon to all of us.
Erlauben Sir mir, dies in meiner Muttersprache zu wiederholen:
Ich wunsche der Konferenz vollen Erfolg und uns alien erfreuliche
Tage in Lyon.
Speech, made by Dr. J .P. Massue from the Council of Europe
at the Opening Session of the 10th International Conference on
Solid State Nuclear Track Detectors.
"As I represent the Council of Europe in the Scientific
Committee of the 10th International Conference on Solid State
Nuclear Track Detectors, I would like in a few words, to explain
why the Parliamentary Assembly has given its patronage to the
conference.
First let me remind you that in our Assembly we have a
Committee on Science and Technology with parliamentarians debating
on scientific and technological problems in Europe. In 1971 the
Parliamentary Assembly adopted an order asking its Committee on
Science and Technology to take action in order:
- to strengthen scientific co-operation in multi-disciplinary
and specific fields of research,
- to create links between parliamentarians and scientists in
order to inform the parliamentarians of the problems of
scientific research and to provide them with mechanisms to
help them in their political decision-making.
Consequently, up "until the conference in Barcelona, the
Parliamentary Assembly has given its support to the International
Conference which represents a unique international forum to discuss
the state of art of the techniques to detect ionizing particles.
We are strongly interested in this field. Indeed, in 1971 a
Working Party on Space Biophysics was created where we used solid
state track detectors with which correlation between cosmic rays
and biological objects could be made. On the other hand, we are
at the moment undertaking action in the field of radiation protection
at the level of training of non-medical staff.
I am sure that the conference will be a success. Firstly,
because you are here, secondly, because we are working under
the Chairmanship of Professor Schmitt who has beautifully organised
the whole conference, and thirdly, I am sure that you will be
charmed by the hospitality and the gastronomy of this city. I
would like here, to thank the Lyon authorities for the help they
have given in the organisation of the conference.
I am convinced that in the future you will remember our
conference saying "I have been to Lyon"."
9
EXTRAIT du poeme en russe et en frangais,
compose par le Professeur C. BOGOMOLOV de MOSCOU,
et declame par lui, lors de la Reception donnee
par M. le Prefet de la Region de Lyon et Madame,
le Mardi 3 Juillet 1979.
(Le Professeur 0. BOGOMOLOV a bien voulu
rediger in extremis cet extrait du poeme,
quelques instants avant son envoi de "Lyon Satolas").
dtfcLttZa*
b*Tf>*SL
ULCKp*HHUK
Le toute mon &me j'aime la France
Mais au Nord je suis n6
J'adresse mon eloquence
Au Rrefet Lyonnais ...
10
Session
1
Fundamental Mechanisms
Chairman: P. Bogomolov
DETERMINATION OF THE
SCREENING PARAMETER FROM
MEASUREMENTS OF DIFFERENTIAL
ENERGY LOSS
A. Aframian
Atomic Energy
Organization of Iran, NRC PO Box 3327,
Tehran, Iran
ABSTRACT
The intensities of forward and lateral scattering of light and heavy
charged particles from the surface of pure materials and compounds have
been discussed, based on the screened coulomb potential, the screening of
which is given by a Thomas-Fermi function § ^ (r/a).
For compounds the
screening parameter has been estimated for multiple scattering of secondary
light charged particles and electrons resulting from the interaction of
heavy energetic (9.6 MeV/nuc), Fe and Kr, ions in quartz crystals and plastic
nuclear track detectors. Thus when chemically etched in suitable solutions,
a measure of individual track diameters, and their rate of increase, as a
function of differential energy loss for primary ions, is obtained. Therefore the itteration of screening parameter as a function of the primary
ionization density, indirectly yields an approximate value, by comparison.
INTRODUCTION
The knowledge of accurate relations between range energy and energy
loss rate for heavy ions in nuclear track detecting materials is a necessary
requirement in the use of this kind of visual detectors; in the present case
the mineral crystal quartz and the polymer Makrofol-KG polycarbonate. These
relations are essential for the studies of the interaction of charged particles with the various detector materials. Thus for establishing the
S.S.N.T.D.—B*
13
14
A.
Aframian
relations between range, energy and energy loss for the primary, heavy ions
1
the methods of Northcliffe and schilling ) and also the direct method of
the calculation of the range according to Heckman et.al ) have been considered.
For the relation of energy loss dE/dX, was obtained by dif3
ferentiating the range-energy expression ) and the modified expressions of
Barkas4) for the density of primary ionization J.
Here an indirect method of measuring the screening parameter by secondary low energy charged particles in quartz and 6-rays in polymeric
detectors will be discussed. Thus the secondary particles were produced
as a result of the interaction of heavy ions e.g. Ar, Ca, Fe, Cu, Zn and
Kr, using multiple energies of 1.04, 414 and 9.6 MeV/nuc from linear accelerator at the university of Manchester U.K.
1.1.
Interaction -of atomic particles at low energies.
The elastic interation of atomic particles by low energies is mainly
due to the coulomb attraction or repulsion of their charges.
In many cases
this interaction can be described very well by a potential of the from
(1)
e and Z^ e are the nuclear charges of the interacting particles, r is
thier distance and <j> (r/a) is a screening function describing the screening
action of the electronic shells which are possibly present. A simple example is the screening function given by Bohr' }.
4>B = exp (- r/a)
(2)
for the screening parameter Bohr gives the approximate value,
(3)
Determination of the Screening
Parameters
This is however, a rough approximation as the individual properties of the
electronic shells are not accounted for. Therefore if the screening function and the screening parameter are known, the differential scattering
cross section can be calculated, and thus making possible the treatment
of consecutive scattering processes, such as multiple scattering, nuclear
stopping, channeling and other similar processes. Thus investigation of
any such processes yields information on the potential. Conclusions of
this kind can be made reliably from direct measurements of the scattering
cross section in single scattering. Thus Firsov et.al^) has suggested a
method of reconstructing the potential from a complete measurement of the
differential scattering cross section.
Measurements of this kind with rare gases^) in the energy interval
between 20KeV and lOOKeV have show for instance, that the Thomas-Fermi
function as the screening function (j>(r/a) in eq. (1) gives a better representation of the potential than the exponential in eq. (2)
The measurements of single scattering cross sections at low energies
requires the use of gas targets of low density.
Beside causing exprimental
difficulties the number of suitable cases which can be investigated are
severely restricted.
In the case of compounds (composite materials) this
is further complicated due to, the mixture of the
constituent atoms
present, and the difficulty of sample preparation, since they should be
thin, for small differential energy loss, and yet self supporting.
A distinct dependence of multiple scattering on the screening is
o
present in the case of low energies as suggested by Meyer ). These calculations were made for energies, at which the process of single scattering
15
16
A. Aframian
can be described by classical mechanics, which corresponds to the presumption that
.
3
=v/c
(4)
for the energy E of the incident particles (i.e. for the secondary generated
particles in this case), this condition is equivalent to
2
2
E < A X Z Z X 25 (KeV)
where
(5)
is the mass of the incident particle.
In the present paper the
determination of the screening parameter is discussed basically by measuring the intensity of forward scattering intensity along the lines proo
posed by Meyer et.al ), and secondly by measuring the differential energy
loss or ionization density both radilly and along the path of a heavily
ionizing charged particle.
2. The intensity of forward scattering as a function of the screening
parameter.
The fraction of the incident particles which are scattered into the solid
angle
<jw around the scattering angle 6 = 0, after penetration of a
g
thickness9t,according to Meyer et.al ) is given by
2
F(0) du> = dca/27T.l/4 e ( l + m 1/ m 2)
2
X {^(T.O)2
2/3
4a N f 2(x,0)}
(6)
where m^ and m^ are the masses of the incident and the scattered atoms respectively, and N is the number of atoms per unit volume of the scattering
material, e , the reduced energy and T the reduced thickness are defined by
(7)
Determination of the Screening Parameters
17
and
x = TT
2
a Nt
(8)
for the functions f^ (T, O ) and f^ (T, O ) the calculated values given
in tables of Ref. 8 have been used.
2 2/3
In eq. (6) the term 4 a N
f^ (T, O) is small in comparison to
f 1 (x, O) and will therefore be neglected. Where neglecting of
(x, o)
leads to significant errors one may proceed by calculating at first the
quantity
AF = i II tr(l+ r y r n ^
2
a
2/3
f 2( r , 0 )
using an approximate value of a, given by eq. (3) and then adding this
quantity to the forward scattering intensity F(0), determined experimentaly.
Therefore in the various calculations F(0), is the experimental value which
has been increased by AF if necessary.
Thus using equations (7) and (8), eq.(6) can be rearranged in the form,
2
8ir Nt
2
2
( Z 2 Z 2 e /E ) F(0) =
(9)
xf^T.O)
2
The right side of eq. (9) is dependent only on T or on a(Nt) =
( T/TT)
2
.
Therefore eq.(9) can be written in the form of eq. (10),where the functional
A
dependence of f
is shown in table (1), and the
(10)
screening parameter can be evaluated experimentally through the determination of F(0), E, and Nt. For the computation of table (1), the function
f(x, o) which has been calculated in Ref. 8, in the interval 0.2 < T < 20
has been supplemented by some values which were calculated from the theory
g
of Moliere ) in the manner given in Ref. 8. Preliminery results according
to equ. (10) indicate that the screening parameter can be determined with
A.
18
Aframian
good accuracy at small thicknesses of the scattering layer, using this
technique. The method is particularly useful for pure metals, where the
particles involved are either due to the scattered primary beam or that of
the target material being detected by a particle detector, e.g a sensitive
surface barrier detector. At large thicknesses there is only a slight dependence of the the exprimental quantities, F(0), E and Nt on the screening
Q
parameter. This is due to the phenomenon noticed by molier ) and discussed by Bethe 1^), that the scattering distribution does not depend substantially on the exact form of the screening function at large numbers of
collisions.
3
Differential energy loss as a function of screening parameter
For compound materials where preparation of a thin target is a dif-
ficulty we have used a number of thin layers, in the case of polymers
usually 10-15 ym thick of nuclear track detecting materials eg. Makrofol-KG
polycarbonate [C^
0^), stacked together. The total thickness of the
stack being a function of the energy and therefore the range of the incident
charged particle1).
The rate of energy loss for heavy ions, (dE/dx) is defined as
-1
( d E / dx ) ^ ( d R / d£ )
(11)
Heckman et.al ) have expressed the range R of an ion with mass M, atomic
number Z and velocity 3c, by the relation:
2
R (($) = ( M/Z ) A ( B
where
)
+
R
.
(
6 )
(12)
is the referential range of an 'ideal* proton with velocity 3c
and the quantity R Q
xt
(3) is the extension in range of the ion, caused by
the neutralization of the moving ion's positive charge by electron capture
when its velocity decreases. Range extension depends on variations of the
*
3
ions effective charge Z and is defined by ):
( Z V M ) Rext
19
= r {(Z/ z* ) - 1 } (dA M B ) d3
(13)
11
Thus Bohr ) proposed to express the probability of capture of an electron
by the ratio:
137 3/Z
therefore allowing the range extension R ext., to be expressed as a function
of 137 3/Z,
Rext. = M z
2 /3
C z ( 137 3/Z )
(14)
3
4
where the same function can be applied to all ions ). Barkas et.al ) modified
12
the classical equations of Bethe and Block ) for energy loss and proposed
a modified formula for the density of primary ionization J, defined by:
2
2
2
2
J = Z eff { In (6 3 ) - 3 + K } / 10
4
3
2
(15)
-2/3
where Z 2eff = Z ( l - e " 1 2 5ZB
), 3 = V/c, y 2 = l / l J 23 , with K being equivalent
to the screening parameter a, in section 2. Thus an itteration of K as a
function of J yields the respective values of the screening parameter, which
will correspond best to that of mean track diameter Vs., residual energy. This
value therefore is an indirect measure of forward and lateral scattering
of secondary light charged particles and or electrons. This is shown in
Figs. (2-5) for makrofol-KG, using 9.6 (MeV/nuc) Fe and Kr ions.
EXPERIMENTAL
In polymeric materials such as Makrofol-KG, differential energy loss
profiles, have been obtained using 10-ym thick layers stacked together and
irradiated with the primary charged particles, e.g. Ar, Ca, Fe, Cu, Zn and
Kr, with any one of the energies 1.04, 4.14 or 9.6 MeV/nuc, from the Manchester
linear accelerator.
Irradiations were carried out at Zero degrees or normal
to the plane of the detectors. After irradiation the detectors were etched
20
A.
Aframian
in a solution of 25% NaoH either at 20 ± 0.5 °C (room temperature) in a
thermostatically controlled bath, or at 6o ± 0.5 ^C, for the required
duration. Observations were made using a Leitz optical microscope
at a
magnification of X630. For mineral crystals such as quartz where suitably
thin targets for differential energy loss measurements were not available,
one millimeter thick crystals were cut along the plane normal to the*C
axis or {ool
} , other minerals such as mica were thinned down to 3 ym
using Ar-ion bombardment. The crystals were highly polished using a lapping
machine and dialap grinding paste containing particle sizes of (a) 6-8ym
(b) (3-6)ym and (c) 0-1 ym respectively, for 15 minutes using steps (a) and
(b), and 30 minutes for step (c). The polished surface was first exposed
to a beam of 9.6(MeV/nuc), Kr-ions, entering the detector surface at 30°
with respect to the plane of the crystal. While in the same orientation
with respect to the beam,the crystal surface was rotated through 90° and
the same procedure carried out this time using 9.6(MeV/nuc) Fe-ions.
Following irradiation the crystals were chemically etched in a boiling solution of 65% NaoH , for 15 minute
durations until intersecting tracks were
observed. Foreaseof handling and to enable easier removal and ultrasonic
cleaning of the detectors, they were tied at the end of a length of insulated
wire and dipped into the etching solution. The detectors were etched progressively for increasing durations and the rate of increase in track length
as a function of residual range for Kr-ions (the longer tracks in Fig.(l) )
were measured. Alternatively for the smaller intersecting tracks of Fe-ions,
their rates of etch along the track V^, at each intersection and increase
in diameters, as they appeared beneath the detector surface were measured
as a function of residual range and energy, thus yielding ionization profiles
similar to that for Makrofol-KG in Figs. (2-5). Tracks were generally etched
upto their maximum etchable length. That is upto a time when they began to
21
show rounded tips. The registration efficiency for Makrofol-KG was
measured to be 96% with critical angle of registration 0 c = 3®. Similarly
the registration efficiency for quartz parallel to the C* and normal to
the C axis were measured to be 97.5% and 94.5% respectively.
Accordingly
the corresponding critical angles were found to be 1.4° and 3.1°.
Results and Conclusions
For compound materials, the screening parameter that is measured is
due to the integrated sum effects of the electronic shells of the individual
constituent atoms forming the material. Thus in Makrofol-KG and quartz the
radial measurements of the tracks of individual charged particles have been
used as a measure of forward and lateral
scattering of secondary ions.
The itteration of the screening parameter in equation (15), for Fe, and Kr
ions in Makrofol-KG is shown in Fig.(3 and 5). Therefore a comparison of the
differential ionization density and the ionzation profile as a function of
track diameter for either Fe-ions Figs.(2 and 3) or Kr-ions Figs (4 and 5),
will show that the itterated value, equal to 8, is a better fit for the
screening parameter in this polymer. Similar treatments for quartz has
set this value at 11, and that for the mineral olivine was found to be of
the order of 20. The measured ranges for the 9.6 (MeV/nuc), Fe, and Krions in Makrofol-KG , 169 ± 5ym and that these ranges in quartz were observed to be 96 ± 2.2ym, and 94 ± 4ym respectively.
The intensity of
forward scattering for thin films of pure materials have been studied.
It has been observed that the intensity of forward scattering show marked
dependence on the screening parameter even at larger values of the thickness,
t, in section 2. It is worth mentioning that in such experiments the effects
of charge transfer and secondary electrons should be accounted for.
A.
22
Aframian
Table (1)
Evaluation of the function f in eg.(10)
2
E
Zj Z 2 Nt F(0)
10~
13
2
eV cm
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.2
1.4
1.6
1.8
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5
12.0
2
f= a(Nt)^
2
0.244
0.268
0.290
0.312
0.333
0.355
0.776
0.420
0.460
0.500
0.540
0.578
0.682
0.795
0.918
1.05
1.19
1.35
1.52
1.70
1.90
2.13
2.39
2.39
2.66
3.77
3.60
3.96
4.37
4.77
5.27
5.86
Determination of the Screening
Parameters
REFERENCES
(1)
L.C. Northcliffe and R.F. Schilling, Nucl. Data Tables A7 (1970)
233.
(2)
H.H. Heckman, B.L. Perkins and W.H. Barkas, Phy. Rev. 117 (1960)
544.
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
E.V. Benton and R.P. Henke, Nucl. Inst, and Meth. 67 (1969) 87.
W.H. Barkas, National Research Council Publication 1133 (1964).
N. Bohr, Mat. Fys. Medd. Kong. Dan. Vid. Selsk. 18. no. 8. (1948)
O.B. Firsov, Zh. Experim. I. Teor. Fiz. 24 (1953) 279.
G. Lane and E. Evenhart, Phys. Rev. 120 (1960) 2064.
L. Meyer, Phy. Stat. Solidi (b) 44 (1971) 253.
G. Moliere, Z. Naturforsch, 3a (1948) 78.
H.A. Bethe, Phys. Rev. 89 (1953) 1256
N. Bohr, Phys. Rev. 58 (1940) 654; 59 (1941) 270.
F. Block, H.A. Bethe, Z. Physik 81 (1933) 363.
23
24
A.
Aframian
Fig. (1): Intersecting tracks of 9.6 MeV/nuc. Kr, and Fe-ions in Brazil
quartz. The crystallographic axis used, was normal to the C axis of
the crystal. For the same total etch time Kr-tracks, have etched
quicker than that of Fe-tracks due to the greater ionization density.
Fig. (2): Mean track diameter Vs residual energy for 9.6 MeV/nuc Fe ions, showing
differential energy loss profile in the polymer Makrofol-KG, for various etching times.
25
26
A.
Aframian
Fig. (3): Plots of ionization density Vs. residual energy for 9.6 (MeV/nuc) Fe-ions,
for the itterated values of the screening parameter 8 and 20.
27
Fig. (4): Mean track diameter Vs residual energy for 9.6 MeV/nuc Kr-ions, showing differential
energy loss profile in the polymer Makrofol-KG, for various etching times.
28
A.
Aframian
Fig. (5): Plots of ionization density Vs residual energy for 9.6 (MeV/nuc)Kr - ions for the
itterated values of the screening parameter 8 and 20.
SOLID KRYPTON EMISSION CHAMBER
A. I. Bolozdynia*, O . K. Egorov*, L . I. Sokolov*,
V. P. Miroshnichenko** and B. U . Rodionov**
*Institute of Theoretical and Experimental Physics
**Moscow Engineer and Physicist Institute
ABSTRACT
A controllable solid state track detector - solid krypton emission
chamber - has been created. The electrons from the particle tracks
in solid krypton under the influence of a constant electric field
are emitted into the gas. Streamer-type track visualisation has
been realised in gaseous neon over the surface of solid krypton.
The pictures of the particle tracks in the emission chamber are
shown in the report. Future possibilities of using the new track
detector are discussed.
KEYWORDS
Solid krypton, streamer, tracks, gas discharge.
INTRODUCTION
The emission chamber is a new type of track detectors, which combine
the advantages of bubble chambers (high density medium) and gaseous
discharge track detectors (controllability and high speed). A simple
two-electrode emission chamber (Pig. 1) consists of two layers - a
gaseous layer and a condensed one - which are placed in an electric
field. The condensed layer, which is used for nuclear interacting
particle detection, is a noble gas in solid state. The gaseous
layer is used for particle track visualisation.
The emission chamber operates in the following way: the electronion pairs, arising along the charged particle tracks, separates and
drift into opposite directions: the electrons move to the positive
electrode and the ions to the negative one. With the polarity
indicated in Pig. 1, the electrons drift to the boundary of solid
and gas layers.
Since the electrons drift velocities are constant for the given
medium and the given electric field, the electrons from all the
track drift alike one single. If the electric field intensity is
29
30
A. I. Bolozdynia et al.
/ / / / • / / / /
Pig. 1
Emission chamber operation principles
1 - the track of a particle, which had
passed through the condensate
2 - intermediate position of the particle
track during the emission through the
boundary
3 - the image of the particle track at the
moment of visualisation
large enough, the electrons overcome the potential surface barrier,
existing at the boundary, and enter the gas. After all the track
image has entered the gas, an additional high-voltage pulse
("visualisation pulse"; is applied to the chamber electrodes. As a
result streamers emerge on the electrons of the track image. So we
have used streamer visualisation of images. In principle, any
other method can be used for the registration of images electron
drifting in the gas. We have used solid state krypton as the condensed medium and neon as the gas for streamer visualisation of
electron images (l). A more detailed description of the emission
chamber processes is given in the paper (2). Beside solid krypton
other noble gases in liquid or solid state can also be used in such
chambers: solid or liquid argon (3), or xenon ( 4 ) . It is practically more convenient to operate with a solid condensed medium.
Solid Krypton Emission
Chamber
31
The chamber construction is shown in Fig. 2. There is a flat condensator inside a hermetized volume. One of the condensator electrodes is the bottom of the chamber, the other is the mesh-type
high voltage electrode of the chamber. There is a transparent
window above the high voltage electrode. The photographing is made
through this window. The distance between the electrodes is 16 mm.
All the system of electrodes is located inside a thermostate with
an internal temperature of 78 K (the temperature of the boiling
nitrogen)•
Pig. 2
The
1 2 3 4 5 6 -
emission chamber construction
mesh-type electrode
the chamber frame
the plexiglass window
the high voltage electrode
Cu-vessel with liquid nitrogen
the heater
An Arcadjev-Marx generator with maximum output voltage amplitude of
300 kV, output capacity of 100
and 60 nsec pulse duration was
used as a voltage power supply for the streamer visualisation. The
size of the beam was determined by two 5 mm scintillation counters
in coincidence. The film sensibility for event photographing in the
chamber was about 2000 units of ASA«
32
A. I. Bolozdynia et al.
The emission chamber performance essentially depends on the gas
purity. The relative molecular impurity7concentrations (0 2. N^,
CO2, HÔ) in the gas must not exceed 10"' (for solid krypton layer
of 1 cm). The gas is purified by compulsory circulation through
calcium oven heated to 650 C. A special z cm3 emission chamber
was used to control gas purity (3). The neon pressure has been
matched to equalise electron drift velocities in solid krypton
and gaseous neon. In such a case an electron image of the event
(in solid krypton) comes through the boundary practically without
changing the form. The drift field intensity was about 1-2 kV/cm.
In this case the electron drift velocity was equal to about
10° cm/sec and the chamber memory time was 1.6 sec.
The visualisation pulse was shaped with the help of a chamber
shunting resistor. The amplitude of this pulse was up to 10 kV/cm.
The pictures of two particles tracks with ionisation very close to
the minimum (3 Gev/c pions) are shown in Fig. 3. On top of the
picture is the track of a particle which had passed through solid
krypton tso called "emission track") and at the bottom is the
track of a particle which had passed through gas ("gas track").
One can see that ionisation density in the emission track is much
higher than the gas track ionisation density. Simple calculations
show that in principle, the emission chamber is able to register
such particles whose ionisation ability is few orders of magnitude
lower than the minimal one.
Fig. '5 Emission and gas track pictures
On the top - emission track picture
At the bottom - gas track picture
Solid Krypton Emission Chamber
33
In general, the possibility of particle track registration in condensed medium by pure electronic method is shown in this report.
Such a method provides for high speed and controllability of
detection.
We believe that such a chamber will be useful in nuclear physics
experiments and first of all for neutral particle detection
{neutrino,gamma rays) and also in applied physics (for example, in
nuclear medicine for radiation field visualisation).
REFERENCES
Bolozdynja, A.I. et al., Lett, to JETE, 2£ (9), 401 (1977)
Rodionov, B.U., "Experimental methods of nuclear physics", Issue I,
p. 36, Moscow, Atomizdat, 1975
Bolozdynja, A.I. et al., Lett, to JTE, '± (2), 64 (1977)
Abramov, A.B. et al., Lett.to JETE, 21, U ) , 82 (1975)
CORRELATION OF REGISTRATION
THRESHOLD W I T H CRYSTALLINITY
STATE OF PLASTIC DETECTORS
A. Chambaudet* and Ph. Romary****
*Lab. de Chimie Physique, Univ. Pierre et Marie Curie, Av.J. Perrin, Bat.3'50,
91405 Orsay, France
Centre des Faibles Radioactivites, Lab. mixte CNRS -CEA, BP no. 2,
91190 Gif/Yvette, France
ABSTRACT
We have recently shown the influence of polymer crystallinity on etched track
characteristics of heavy ions. F o r ethylene glycol polyterephtalate (terphane or
mylar) and polypropylene p o l y m e r s , it has been observed that the registration
thre shoId (dE/dx )^ is notably higher in amorphous samples than in crystalline
ones. Further experiments achieved on terphane indicate that various p a r a m e ters influence the threshold value only in the amorphous samples :
- storage time between irradiation and chemical etching.
- thermal treatment of irradiated samples before development.
- conditions of chemical etching (nature of etching solutions, time required for
development).
These observations lead us to conclude to a rapid stabilization of the etchable
track in crystalline terphane whereas stabilization would occur m o r e slowly in
the amorphous plastic detector.
KEYWORDS
Track ; plastic detector ; polymer ; ethylene glycol polyterephtalate ; mylar
terphane ; crystallinity ; irradiation damage ; registration threshold.
INTRODUCTION
Previous experiments achieved on two heavy ion track plastic detectors (ethylene
glycol polyterephtalate - m y l a r or terphane - and polypropylene) have shown that
the degree of crystallinity is, among other factors, responsible for the poor r e produc i bility of track characteristics : the etched tracks obtained are significantly longer in crystalline samples than in amorphous ones(Bernas, Chambaudet
and Romary, 1977 ; Chambaudet and Romary, 1976). The etching solution used
was a 6. 25 N NaOH solution at a temperature of 5 5 ° C . To obtain a better quality
of the etched tracks, a milder p r o c e s s by NaCIO was then used. F a c t o r s such as
storage time of an irradiated sample before the chemical etching or storage t e m S.S.N.T.D.—C
35
36
A. Chambaudet and P h . Romary
perature appeared to lead to poor reproducibility. The following study deals with
the detailed effects of such factors.
INFLUENCE O F THE N A T U R E O F THE E T C H A N T
Ethylene glycol polyterephtalate (terphane from La Cellophane, France) either
completely amorphous or 85°/ D crystalline (checked by X R diffraction) have been
examined. The film characteristics and the irradiation conditions have been d e s cribed elsewhere (Chambaudet, 1977).
Re suits
The etching process with NaOH (6, 2 5 N) at a temperature of 55°C leads to the
registration of the two fission fragments in crystalline terphane when the ion
bombardment is from a ^ ^ C f source, while only the light fragment is recorded
in amorphous samples;in Fig. 1, the length of the etched track (L) is plotted v e r sus etching time for both f o r m s .
F F h = heavy fission fragment
F Fi slight fission fragment
0
30'
1h
1h30' etching time
Fig. 1. Variation of fission fragment track lengths ( ^ ^ C f ) in 8 5 % crystalline t e r phane (TX) and amorphous terphane (TA) etched with 6, 25 NNaOH at 55°C
Fig. 2. Variation of fission fragment track lengths (252 cf) i n 85% crystalline
terphane (TX) and amorphous terphane (TA) etched with NaCIO at 5 5 ° C
Correlation of Registration
Threshold
37
If the chemical etchant is NaCIO, the n e c e s s a r y etching time at the same temperature is longer (20 hours instead of 1 hour 30 minutes). In such conditions, the
two fission fragments are observed in both f o r m s of terphane (Fig. 2 and Fig. 3)
(Romary, 1977).
Number of tracks
40
Amorphous terphane
30
6hours
19hours
etching time
20
10
2
40
30
3
4
5
hi
6
7
8
9
Number of tracks
measured track
length ( m m )
8 5 % crystalline terphane
etching t i m e : 6 hours
fi
20hours
20
10
2
3
4
5
2
6
7
J
8
L_
9 measured track
lenght ( m m )
2
Fig. 3. Number versus length of ^ C f fission fragment tracks in amorphous and
85% crystalline terphane etched with NaCIO at 5 5 ° C .
A similar result is obtained after 1 MeV K r ° ion bombardment : the length of
the etched tracks in a 85% crystalline sample is the same for both etching treatments (NaOH or NaCIO) whereas in the amorphous form the tracks are longer
with the NaCIO etching p r o c e s s .
These results can be compared with the effect obtained upon mild thermal treatment achieved on irradiated samples before etching. We observed then (Bernas,
Chambaudet and Romary, 1977, Fig. 7) a constant track length in 85% c r y s t a l line form while the track length is increasing to a maximum value for a 1 hour
- 50 °C treatment of an amorphous sample. Nevertheless, the observed etched
track length is always shorter in the amorphous samples. These observations
lead us to suggest that the same thermal effect occurs at 5 5 ° C during the etching
process with NaCIO.
The registration threshold is then obtained from the etched track length using a
method previously described (Bernas, Chambaudet and Romary, 1977) and summarized in Fig. 4. The results are gathered in Table I. We note a significant difference in the thresholds for the amorphous form between NaOH development
1
2
1
2
(42, 1 MeV. cm , m g " ) and NaCIO treatment (28 MeV. c m , m g " ) .
38
A . Chambaudet and Ph. Romary
range ( j i m )
dE
«1
2
^ ( M e V . m g - .cm )
70
20
equivalent
range in air
16
50
v
12
60
revealed r a n g e (L)'m
amorphous terphane
30
(7,5 jim)
8
AO
1
""/ /dE\=28MeV.mg- cm
20
A
7
10
J_
0
0,2
0,4 0,6
E t = 0,16 MeV/N
0,8
_L
1 Energy
(MeV/N)
0
2
dx threshold
0,2
0,4
0,6
J_
0,8
1
Ethreshold
Energy
(MeV/N)
Fig. 4. ( d ^ / d x ^ j ^ j ^ - ^ determination from revealed track length (L) for the
light fission fragment of ^ ^ C f in amorphous terphane (etchant :
NaCIO at 5 5 ° C )
xx E m : emission energy of the light fission fragment
x E Q , energy and ( d E / d x ) Qt L . E . T , of the light fission fragment at the
surface of the plastic detector .
2
52
Cf
fission fragment
light
= 0, 72
° (MeV/N)
63,8
dx o
2
(MeV. m g - ) c m )
heavy
E Q = 0,32
(MeV/N)
L
etching A m o r p hous te rphane
o conditions
L
E
V
J
t
dx t
E
H-)o= 55. 5
(
(MeV. m g ~ \ cm^)
14, 4
11
85°/G c rystalli ne terp.
(dE^
E
L
clx t
t
6, 25 N
NaOH
55°C
5, 2
0, 28
42,1
11, 8
0, 04
10
NaCIO
55°C
7, 5
0, 16
28
12, 3
0, 04
10
6, 25 N
NaOH
55°C
not detected
-
-
8, 9
0, 03
10
0, 12
28
9
0, 03
10
NaCIO
55°C
5, 2
T A B L E I . Critical energy (E^) and track registration threshold
( d E / d x ) t in amorphous terphane and 85% crystalline terphane for
the two etching conditions.
E Q energy and (dE/dx)Q linear energy transfer at the surface of
the plastic detector (Northcliffe and Schilling, 1970)
X X
L Q theoretical range in the detector (Northcliffe and Schilling,
1970)
L etched track length in amorphous terphane and 85% crystalline
terphane.
Correlation of Registration
39
Threshold
I N F L U E N C E OF STORAGE TIME B E T W E E N IRRADIATION AND
CHEMICAL T R E A T M E N T .
According to the preceding observations, it s e e m s plausible to propose that a reorganization of the latent track takes place after irradiation. Such a p r o c e s s could o c cur at room temperature and it was interesting to follow its kinetics.
Chemical etching either by NaCIO at 5 5 ° C or by NaOH at the same temperature,
performed on irradiated samples after 1,15 or 30 days of post-irradiation time,
lead to the results gathered in Table II. F r o m these, the following remarks can
be made :
a) For both developments, the length of the etched track is the same when the
plastic used is 85% crystalline terphane.
b) On the other hand, in amorphous terphane films, we note that :
1) With NaCIO development the length of etched tracks is independent
of storage time,
2) With NaOH development, the greater the storage time, the longer
is the etched track of the light fission fragment. Moreover, the heavy fission
fragment track becomes etchable after 1 month of storage time. For such a postirradiation time, the lengths of etched tracks are identical with those obtained
upon NaCIO development.
To summarize :
x For 85% crystalline samples, no track length difference is observed after
1 day or 1 month of post-irradiation time.
x For amorphous terphane, 1 month of storage time of irradiated samples is needed to obtain identical results for both chemical etching p r o c e s s e s .
2
52
fission
Cf
fragment
light
E Q = 0, 72
(MeV/N)
( d E / d x ) Q = 63, 8
2
(MeV. mg~l c m )
heavy
E G = 0, 32
(MeV/N)
( d E / d x ) Q = 55, 5
2
(MeV. m g " \ c m )
L
o
(M m)
A t
(day)
1
14, 4
11
Etchant : NaCIO at
Etchant: NaOH (6,25 N)
55°C
at 5 5 ° C
L
L
L
L
amorphous
85% c r y s - amorphous 85% c r y s 4
(I m)
talline (jUm). ( / 4 m)
talline (A<m)
7, 5
12, 3
5,2
11, 8
15
7, 4
12, 2
6,2
12
30
7, 4
12
7,5
11, 9
1
5, 2
9
8, 9
15
5, 2
9
not
detected
not
detected
30
5, 3
9
5, 5
9, 1
9
T A B L E II : Mean lengths (L) of
Cf fission fragment tracks
etched with NaCIO or NaOH versus post-irradiation time in am
phous terphane and 85% crystalline terphane.
E , (dE/dx)
and L , see table I .
o
o
o
40
A. Chambaudet and Ph. Romary
CONCLUSION
The significant difference in the etched track length observed between amorphous
and crystalline plastics appears now well established. Complementary experiments have further shown :
a)the stability of etched tracks in 85% crystalline terphane versus time or v e r sus temperature,
b) the evolution of etchable tracks in amorphous samples :
- with a thermal treatment performed before chemical etching
- with a thermal effect during the etching p r o c e s s
- with storage time at room temperature of irradiated f o i l s .
After either of these treatments is performed^the length of etched tracks appears reproducible in amorphous samples.
These results suggest that the kinetics of stabilization of the latent etchable
track are rapid in the crystalline detector while they are v e r y slow in the a m o r phous plastic.
These observations suggest that different degrees of crystallinity of the p o l y m e ric track detector seem to lead to a different distribution of the latent damages
around the trajectory of the incident particle, thus explaining the difference in
the etched tracks.
ACKNOWLEDGEMENT S
We would like to express our thanks to D r . A . Bernas for her continuing interest in this work and the D r . F. Kieffer for critical comments.
REFERENCES
Bernas, A . , A . Chambaudet and Ph. Romary (1977). Effet du taux de cristallinite d'un
detecteur plastique sur les caracteristiques de traces d'ions lourds. Rad.
Effects, 32 , 1-8.
Chambaudet., A.^ and Ph. Romary (l976).On the variation of some heavy ion
track characteristics with the polymeric detector crystallinity. Proceedings of
the 9th I.C. N. T. D0) Neuherberg/Munchen , Solid State Nuclear Track Detectors,
I, 3 0 7 - 3 1 6 (1978).
Chambaudet, A . (1977). Contribution a l'etude du m e c a n i s m e des traces d'ions
lourds dans quelques detecteurs polymeriques. These d'Etat, P a r i s , pp 1 2 6 - 1 8 4 ,
Northcliffe, L . C v and R. F . Schilling (1970).Range and stopping-power tables
for heavy ions. Nuclear Data, Tables, A 7 , 3 - 4 , 2 3 3 - 4 6 3 .
Romary, Ph. (1977).Effet du taux de cristallinite du detecteur sur l'enregistref
ment des traces d'ions lourds dans le polyterephtalate d ethylene glycol et le
e me
polypropylene. These 3
cycle, Paris .
RADICALS IN TEFLON FOLLOWING
HEAVY ION OR ENERGETIC
ELECTRON BOMBARDMENT.
CORRELATION W I T H
LATENT TRACKS
A. Chambaudet (L.A. 176) and J. Roncin (L.A. 75)
Laboratoire de Chimie Physique, Bdtiment 350, Avenue Jean Perrin,
91405 Orsay, France
ABSTRACT
We have previously shown a correlation between the existence of heavy
ion latent tracks in most plastics and the formation of "carbon-like"
radicals such as are produced in polymer pyrolysis. The only exception was for teflon, a polymer in which etchable tracks have not so
far been reported and for which RO* radicals were observed. This present paper shows that in the absence of oxygen,a "carbon-like" radical is also observed as for other plastic detectors, the contact with
0^ giving very quickly RO*. We suggest therefore that the absence of
etched tracks is not due to the absence of latent tracks, but to a
failure to find a suitable efficient etching procedure.
KEYWORDS
Track formation ; heavy ion damage ; electron damage ; polymer
teflon ; ESR spectroscopy.
INTRODUCTION
For heavily ionizing particles, the formation of latent tracks in
plastics is generally associated with chemical damage (Katz and
Kobetich, 1968 ; Monnin, 1970). Since the bombardment of the same
polymeric detectors by energetic electrons does not give rise to etchable tracks, it seemed worth while to compare the primary chemical
transformations in the same plastic induced either by heavy ion or
electron bombardment. We have previously (Bernas, Chambaudet and
Roncin, 1975 ; Chambaudet, Bernas and Roncin, 1977 a ; Chambaudet,
1977 b) examined by ESR spectroscopy two kinds of polymeric track detectors (typical nuclear track detectors : makrofol, kapton, terphane,
and polymers whose radiolysis under ^ rays or electron beams is well
known :
41
A. Chambaudet and J. Roncin
42
polymethylmetacrylate,polyethylene, polypropylene) irradiated by heavy ions or electrons- The results led us to suggest that the existence of heavy ion latent tracks might be correlated with the formation of free radicals characterized by the free electron extending
over a number of carbon cycles or conjugated linear chains such as
are produced in polymer pyrolysis (Jen, 1960) and which we called
"carbon-like" radicals. As teflon does not give rise to etchable
tracks (Tretyakova and Djolos, 1978), it seemed worth while to realise further experiments on it. Primary observations by ESR spectroscopy show the very rapid production of peroxide radicals RO"
(Chambaudet, Bernas and Roncin, 1977 b) in contrast with the other
plastic track detectors. We thought then that the RO* formation can
be responsible of the absence of revealed tracks. As the irradiation
and observation are made without oxygen, RO* is probably formed during
the transfer of the samples.
EXPERIMENTAL
CONDITIONS
Further experiments where then carried out on teflon (FEP,Pirep)using
a completely new cryostat (fig.l)(Chambaudet, 1977 a)excluding the
oxygen completely from irradiation to analysis. The plastic films
(50,8 or 2 5 4 M m thickness) are then irradiated at a temperature of
roughly 159°K and maintained at 77°K till observation. The samples are
cooled during bombardment by conduction of a copper piece directly
connected with a liquid nitrogen dewar A. After irradiation, the closing position of the cryostat (c—~c', d — ^ d ' ) lets liquid nitrogen
into dewar B, submerging the plastic foils.
The heavy particles used were
Ar or Kr ions of various charges and
T
energies (200 - 500 MeV)- ê irradiated samples are then examined by
ESR spectroscopy at 77°K with a JEOL ME IX spectrometer.
Liquid nitrogen supply
Copper piece
[Thermocouple
Incident
Guide for
closing
dewar B
beam
Plastic foil
DewbrB
Fig.1.Cryostat during irradiation
R a d i c a l s in
Teflon
43
RESULTS
Typical signals obtained following heavy ion or energetic electron
bombardment are shown in Fig. 2, 3 and 5. In each case, the ESR signals
amplification
ratio 1
omplificotion
ratio 0,56
Fig. 2 ESR spectra of teflon foils (250 /i m thickness)
irradiated by 300 MeV Ar 1 ions (150 Mrad)
(a) at 77°K (A.Chambaudet s cryostat)
(b) 7 minutes after admission of oxygen.
Fig.3.ESR spectra of teflon foils (250 \i m thickness)
irradiated by 300 MeV Ar
ions (50 Mrad)
(a) at 77°K (A.Chambaudet's cryostat)
(b) 24 seconds \
(c) 54 seconds \ after admission of oxygen
(d) 5 minutes I
S.S.N.T.D.—C*
44
A. Chambaudet and J. Ronein
indicate the very rapid production of peroxide radicals RO* .For ion
irradiations, corresponding to a shorter particle range, RO*formation
is more rapid (see e.g. spectrum 3, b obtained 24 seconds after admission of oxygen). On the other hand, previous to this RO^ spectrum,
another fundamentaly important signal which is structureless is recorded, indicating the initial formation of "carbon-like" radicals
such as are produced with typical nuclear track detectors (Fig.4 makrofol).
Fig.4.ESR spectra at 77°K of makrofol2 4K.G.
+
ions
foils irradiated by 500 MeV K r
(a) 2 Mrad
(b) 10 Mrad
(c) 60 Mrad
If a latent etchable track is directly correlated with the presence
of "carbon-like" radicals as we suggested previously (Bernas,
Chambaudet and Roncin, 1975), latent tracks must exist in irradiated
teflon plastic foils. But, contrary to the other polymeric track detectors, these tracks would not be stable at room temperature in the
presence of oxygen."Carbon-like" radicals are immediately changed to
RO* radicals which can inhibit the etching process.
Following
electron irradiation, the first observed signal is due to
#
(R ) radicals (Fig.5), but never to such radicals as are obtained with
heavy ion bombardment in teflon.
ATTEMPTED DEVELOPMENT OF TRACKS IN TEFLON
If our suggestion is right, it would be possible to reveal latent
tracks in teflon if the chemical etching process occurs completely
in the absence of oxygen. According to this assumption, further experiments consisted in a chemical attack of teflon in liquid ammonia
solution of sodium at low temperature during several hours or days.
Such a process is among the rare etching possibilities of teflon.
Experiments are made usirjg an equipment (Belloni, 1969) with which it
is possible to produce sodium metal "in situ" by thermal decomposition
Radicals in Teflon
45
Fig.5.ESR spectra of teflon foils (250 urn thickness)
irradiated by 1,6 MeV electrons (60 Mrad)
(a) at 77°K, with a sample degassed before irradiation
(b) 13 minutes after admission of oxygen
(c) at 300°K after redegassing.
1
of NaN^ in vacuo according to Ebert s method (Ebert, 1958).
The etched plastic becomes brown at the location of the ion impact
and some revealed damages look like tracks. This observation is supported by the results of Calvin Maybury and Libby (1975) using a
grafting process with the free radicals in the tracks in the absence
of air confirming thus that latent tracks exist in teflon.
CONCLUSIONS
The non-observation of etched tracks in teflon is therefore not due
to the absence of latent tracks, but to a failure so far to find
a suitable efficient etching procedure. Moreover, it seems that RO*
formation is responsible for this inhibition of chemical etching.
Finally, these experiments on teflon confirm what we suggested previously (Bernas, Chambaudet and Roncin, 1975), namely that the existence of heavy ion latent tracks might be correlated with the formation of "carbon-like" radicals.
ACKNOWLEDGEMENTS
The author?would like to express their thanks to Dr.J.Belloni for
experiments with the sodium-ammonia solution. Dr.A,.Bernas for critical comments and Jean-Claude Lagron for his important contribution in
planning the cryostat.
46
A . Chambaudet and J. Roncin
REFERENCES
B e l l o n i , J . ( 1 9 6 9 ) . R e a c t i o n e n t r e l ' h y d r a z i n e e t l e sodium dans 1 * ammoniac l i q u i d e . I n t . J . R a d . P h y s . C h e m . , 1, 4 4 1 - 4 5 0 .
B e r n a s , A. , A.Chambaudet and J . R o n c i n ( 1 9 7 5 ) . S u r l a f o r m a t i o n d e s
t r a c e s l a t e n t e s d ' i o n s lourds e t l e s degats chimiques i n d u i t s
par f a i s c e a u x d ' i o n s ou d ' e l e c t r o n s dans l e p o l y m e t h a c r y l a t e
de m e t h y l e . I n t . J . R a d . P h v s . C h e m . , 1 , 4 4 7 - 4 5 5 •
d
a
n
W . F . L i b b y ( 1 9 7 5 ) . Non e t c h i n g o p t i c a l d e t e c C a l v i n Maybury /
t i o n of f i s s i o n t r a c k s using t e f l o n . N a t u r e , 2 5 4 , 2 0 9 .
Chambaudet, A . ( 1 9 7 7 a ) . C o n t r i b u t i o n
a 1 ' e t u d e du mecanisme de
f o r m a t i o n d e s t r a c e s d ' i o n s l o u r d s dans q u e l q u e s d e t e c teurs polymeriques.
Thesis, P a r i s . Chap.6, p p . 2 0 7 - 2 7 1 .
Chambaudet, A . , A . B e r n a s and J . R o n c i n ( 1 9 7 7 b ) . O n t h e f o r m a t i o n o f
heavy i o n l a t e n t t r a c k s i n p o l y m e r i c d e t e c t o r s . Rad. E f f e c t s . ,
14/ 5 7 - 5 9 .
E b e r t , G. ( 1 9 5 8 ) . E i n f a c h e s V e r f a h r e n zur D a r s t e l l u n g von N a t r i u m l o s u n g e n i n f l u s s i g e m Ammoniak. Z . A n o r q . A l l g . C h e m . ,
294,
129- 134.
J e n , C . K . ( 1 9 6 0 ) . E l e c t r o n spin resonance s t u d i e s of trapped r a d i c a l s
In A . M . Bass and H . P . B r o i d a ( E d . ) , F o r m a t i o n and T r a p p i n g
of Free Radicals.> Academic P r e s s , New Y o r k , pp 2 1 3 - 2 5 6 .
K a t z , R., and E . J . K o b e t i c h ( 1 9 6 8 ) . F o r m a t i o n o f e t c h a b l e t r a c k s i n
d i e l e c t r i c s . Phys.Rev.. 170, 401-405Monnin, M. ( 1 9 7 0 ) . Mecanisme de l a f o r m a t i o n d e s t r a c e s dans l e s
p o l y m e r e s . R a d . E f f e c t s , 5., 6 9 - 7 3 .
PROPERTIES AND TECHNOLOGY OF
MONOCRYSTALLINE
AgCl-DETECTORS
1. ASPECTS OF SOLID STATE
PHYSICS
F. Granzer*, E. Schopper** and T h . Wendnagel**
*Inst.f. Angewandte Physik, R.Mayer-Str.2, 6000 Frankfurt 90,
Federal Republic of Germany
Inst.f. Kernphysik, August Euler-Str.6, 6000 Frankfurt 90,
Federal Republic of Germany
ABSTRACT
The formation of latent tracks in AgCl-detectors is based on fundamental mechanisms
similar to those ruling the photographic process in silverhalide emulsions. As a
homogeneous monocristalline well-defined solid state system the AgCl-detectors exhibit, however, particular properties beyond the range of nuclear emulsions.
A model will be presented which describes the response of the AgCl-detectors to
charged particles under recent aspects. It takes into account e.g. the influence
of doping and of the structural conditions induced by growth, thermal treatment,
and plastic deformation.
KEYWORDS
Monocrystalline AgCl-detectors, photographic process, dislocations.
INTRODUCTION
In the last decade, thin monocrystalline AgCl-crystals, doped with cadmium up to
5000 ppm, turned out to b e powerful solid state nuclear detectors for fast moving
heavy charged particles (see, e.g., Schopper and others, 1972a, Granzer and others,
1972, and Haase and others, 1 9 7 7 ) . The unique properties of these AgCl-detectors,
opening them a wide field of applications (see Schopper and others, 1972b, Baumgardt
and others, 1975) are due to the fact that, contrary to nuclear emulsions and many
other track detectors, they constitute a well defined solid state system. Thus their
response to ionizing particles can be completely described on the basis of our present
knowledge of the electronic and ionic properties of the silver halides. These properties, in turn, depend, in a very sensitive way, on the thermal history, i.e.,
on the conditions of growth of the monocrystalline AgCl sheet crystals. The present
state of art of our crystal growth techniques gives us the possibility to modify the
growth conditions in a very reproducible w a y . Thus monocrystalline AgCl-detectors
with well defined physical and chemical properties are obtained.
The following part(part 1)briefly describes the initial state of the AgCl-detector.
In part 2,the response of the detector to a penetrating heavy ionizing particle will
be sketched together with the subsequent ionic and electronic rearrangement- and relaxation processes leading to the latent image of the particle track. Finally, in
part 3, the large influence of the thermal history and treatment with respect to track
detecting properties of the AgCl-crystals
will be discussed. A mechanism will be
presented which explaines the observed improvement in the quality of particle tracks
if the AgCl-detector contains residual plastic deformations.
47
48
F. Granzer, E . Schopper and Th. Wendnagel
1 . PROPERTIES OF AgCl-DETECTOR
CRYSTALS
Using two different crystal growth techniques (Haase and others in 197o and Wendnagel in 1973) thin sheet crystals with dimensions of 25x15x0.3 m m 3 as well as m o nocrystalline foils of areas up to 70x700 m m 2 and thicknesses between 0.05 and 0.35
mm were obtained. Generally the crystals were orientated towards a (100)-crystallographic plane, parallel to the sheet or foil plane respectively. Depending on the
temperature-time-program controlling the cooling-down-period of the crystals in the
furnace - for more details see the contribution of Wendnagel (1979) - detectors
with different and reproducible properties could be obtained.
From the viewpoint of solid state physics and with regard to their expected response
to heavy ionizing particles, the initial state of a cadmium-doped-AgCl-crystal will
be mainly given by its real structur (dislocations and point defects) and their influences on the mechanical properties and the electronic and ionic transport phenomena of the crystal.
1.1 Mechanical Properties
The plastic behaviour of crystals generally depends on the density and distribution
(either isolated or arranged in networks or subgrain boundaries) of the dislocations
and their interaction with point defects or small precipitations. In pure AgCl-crystals as well as in such crystals doped with cadmium up to 5000 ppm the dislocation
density ranges from 5 x 1 0 6 to 1 0 8/ c m 2. While it was possible to reveal dislocation
networks and subgrain boundaries in pure crystals by appropriate decoration techniques (e.g. photolytic precipitation of silver after exposure to UV-light) they
could not be detected in heavily doped crystals whether the dopant hinders dislocations to arrange in networks or boundaries or the dopant prevents their decoration.
The strong interaction between the dopant and dislocations is clearly proved by
Fig. 1, showing the drastic change from "pencil"-glide, Fig. 1a, (typical for the
plastic deformation of pure AgCl, due to the fact that all planes containing the
Burgersvector are activated for slip with the same probability) to anisotropic,
rhombododecahedral glide on {110}-planes (Fig. 1b) encountered in alkali halides
with rock salt structure.
Fig. 1a. Plastic deformation of pure AgCl;Fig. 1b. Plastic deformation of AgCl,
doped with C d 2'
Monocrystalline
AgCl-Detectors
49
2+
As the solubility limit of C d in AgCl, corresponding to 300 ppm at room temperature, i s largely exceeded in "standard" detector crystals doped with cadmium up
to 5000 ppm, the observed embrittlement may be due to the interaction of dislocations either with precipitation
of a cadmium-rich phase (precipitation hardening) or
2+
with solute divalent C d ions, isolated, or associated with negatively charged
silver ion vacancies to neutral dipoles. The l a t t e r mechanism, based on models developed, for instance, by Fleischer (1962) and Frank (1967), seems to be the most
probable and efficient because the drastic
change in the plastic behaviour of AgCl
2+
crystals i s already observable at C d -concentrations far below the solubility
limit showing that the mobility of dislocations in ionic crystals i s controlled by
the amount of divalent impurities dissolved in the host-crystal.
1.2 Electronic and Ionic Transport Phenomena; Space Charges and Surface Potentials
1.2.1 Pure AgCl crystals. As already mentioned, the response of the AgCl detector
crystals to a fast moving charged particle w i l l be governed by the concentration,
l i f e time, and mobility of electrons and holes released by the ionizing particle
and the concentration and mobility of ionic defects. The latter properties
are
+
given by the thermal disorder which i s of the Frenkel type in the Ag -sub-lattice
of pure AgCl-crystals. A l l relevant data characterizing electronic and ionic processes in pure AgCl at room temperature and - for comparison - also in pure AgBr are
listed in Table 1.
By virtue of the outer crystal surface but also by means of inner surfaces (single
dislocations, dislocation networks, grain boundaries, e t c . ) the formation of a
Frenkel defect can be seperated in two steps: Firstly the formation of a silver ion
vacancy by migration of a silver ion from a normal l a t t i c e s i t e to a kink s i t e on
the crystal surface or to a dislocation jog; and secondly the injection of a silver
TABLE
1 Data controlling Transport Processes in Pure AgCl
T
Crystal
AgCl
e
T
h
1o
AgBr
o.1-1o o.1-1o
y
e
p
%
h
o. 15o o.384
2 . 5 - 1 0 " 2.6-1o
6o
1
1.o6
o. 145 o.35o
1.06-10
(holes),
[\i s e c ]
Driftmobility
_
N . ^ 2 . e
of electrons
(holes),
2kT
'
v
i(v)
=
v
i(v)
Formation enthalpy of a Frenkel
Ui
: Migration
N
V
i(v)
Vo
i(v)
10
v
2-1o
3.o-1o'°
8-1o
b
b
2
[cm /V.sec]
U
g p:
F
-3
v
i
1.25
P e( v » h) :
n
v
-5
o.4
Lifetime of electrons
=
v
5o
T e( x h) :
n_
F
4
U
U.
l
_ i(v)
kT
^
defect,[eV]
activation energy for interstitials
(vacancies), [eV]
[cm 3n]
Concentration of Frenkel defect
Concentration of Ag - Ions on lattice sites, [cm" ]|
Jump frequency o f interstitials
Debye-frequency,
1
[1o ^sec
1
]
(vacancies),
1
[sec" ]
F. Granzer, E . Schopper and T h . Wendnagel
50
ion from a kink s i t e or a dislocation jog into an i n t e r s t i t i a l position. Depending
on the difference between the formation energies of vacancies (Ey) and i n t e s t i t i a l
ions (E^) - the sum of both must equal the formation energy of a Frenkel pair - a
surface potential is built up which i s negative i f E v > E-£ and positive i f Ei>E v.
In the former case, a negative surface charge i s neutralized by a diffuse positive
space charge, in the latter the situation is just reversed. As may be seen from
Table 2, where surface potentials measured by different methods are collected together with the corresponding formation energies E v and E^, the surface potentials
(|>s (or line potentials around dislocations) in most cases are positive in pure AgCl
crystals corresponding to a positive surface or line charge (the l a t t e r resulting
from the deposition of silver ions along the dislocation lines) surrounded by a
diffuse space charge consisting of negatively charged silver ion vacancies. This
situation, schematically sketched in Fig. 2a, would be unfavourable with respect
to the detector properties of AgCl crystals: Electrons, released by the ionizing
particle, then would be attracted to the dislocations, thus f a c i l i t a t i n g the precipitation of silver along the dislocation lines but, in doing so, they would be
lost for the formation of a stable latent image of the p a r t i c l e .
1.2.2
AgCl-crystals doped with cadmium up to 5000 ppm. Doping with divalent cations,
2+
like C d , reduces the concentration of i n t e r s t i t i a l silver ions and increases the
number of 2+
silver ion vacancies roughly about the amount of s u b s t i t u t i o n a l ^ dissolved C d - ions as a consequence of the mass action law and the demand for
charge neutrality. As evidenced by ITC (ionic thermo current) - and ionic conducti v i t y - measurements, as done by Wentz and others
(1976) a large fraction (about
2+
80% at room temperature) of the dissolved C d - ions i s associated with silver ion
vacancies forming neutral dipoles.
2+
As a consequence of the suppression of i n t e r s t i t i a l silver ions in C d - doped
crystals, the dislocation lines do no longer act as sinks for silver ions; they
rather w i l l represent sinks for silver ion vacancies, thus leading to a negative
TABLE 2 Surface Potentials (<J> ) and Formation Energies for Interstitials (Ejând
Vacancies (Ev) for Pure AgCl at Room Temperature
Method
Author
Blakely
uy/
*'
Kelvin
Friction
Slifkin
n.9q)Internal
( 1
6f7 i ?
Indentation
and o t h e r s
Ke±vin
Kliewer (1966)
o.3o - o.55
0.08
E ±[eV]
1.o7
- 1.3o
o.86
E v[eV]
o.29 - 0.06
o.58
- o.16 - o.43
o.56 - 1.15
o.88 - o.29
—
- o.o9 - o.51
Sheet Crystal
(Detector)
o.63 - 1.22
o.81 - o.22
Bulk Crystal
Heuser (1979)
<j>s[Volt]
Theory
o.32
o.93
o.28
Monocrystalline
51
AgCl-Detectors
2+
line charge which, surrounded by a diffuse space charge of C d
- ions, will give
rise to a negative surface (or line) potential. Then, as sketched in Fig. 2b, electrons w i l l be repelled from the dislocation lines into regions where they may contribute efficiently to the formation of a stable latent image of the particle track.
Lifetime, mean free path- and drift-mobility of electrons and holes are reduced in
doped crystals compared with pure ones. This has been proved by measurements of
photo conductivity and micro wave absorption. This must be attributed to the introduction of traps for electrons as well as for holes into the forbidden zone separating the valence from the conduction band by doping the AgCl crystals with cadmium.
Fig. 3a shows the shape of the valence and conduction bands in the energy momentum
representation along two prominent direction in the first Brillouin zone. The width
of the energy gap in the simplified zone scheme of Fig. 3b corresponds to the indirect transition indicated by the arrow in Fig. 3a. From absorption- and lumines2+
cence experiments it is w e l l known that s u b s t i t u t i o n a l ^ dissolved C d
- ions act
as electron traps when situated about 1 eV below the conduction band; Kanzaki (1973).
Silver ion vacancies, on the other hand, may trap holes by forming V-centers about
0.6 eV above the valence band; Malinowski (1966). Besides these two energetically
well defined terms, there exists a nearly continuous spectrum of terms (dashed regions in Fig. 3b) corresponding to boundaries separating cadmium-rich precipitations
from the surrounding AgCl-matrix in heavily doped crystals. Finally, as will be
more detailed discussed in part 2, small silver aggregates, formed during the passage of the ionizing particle, may act, depending on their sizes, as electron traps
of varying depths.
a) Pure AgCl-crystal,
b ) AgCl-crystal, doped with
Fig. 2. Competition between particle track and dislocations
E(k)
[ioo]
0
cadmium
E(x)
Cm]
Fig. 3a.Band structure of AgCl
Fig. 3b. Levels of possible traps in the
1
p n PTcr\7
can
52
2. RESPONSE OF THE AgCl-DETECTOR TO FAST MOVING HEAVY CHARGED
PARTICLES
The events and mechanisms caused, in cadmium doped AgCl-crystals, by the passage of
an ionizing particle have already been discussed in full detail, see Granzer and
others (1972), Haase and others (1973), using the terminology and the formalism of
classical photography to describe the formation of the latent image. It, therefore,
may be justified in this place to summarize only the essential steps leading to a
stable latent image of the particle track which may b e amplified lateron by suitable
decoration techniques.
2.1 The Self-Sensitizing of the Particle Path
After the fast decay of excitation and higher ionization states and as a result of
subsequent relaxation processes (Coulomb-explosion, Groeneveld (1979), Varleymechanism, Varley (1954)) a narrow cylindrical region, surrounding the path of the
particle, will be filled with electrons, holes, silver ion vacancies, and interstitial silver ions. Thus, contrary to a bulk crystal, which is almost completely
depleted from interstitial silver ions as a consequence of cadmium doping (see part
1 . 1 . 2 ) , the concentration of interstitials is considerably enhanced around the trail
of the ionizing particle and by repeated recombination with electrons small silver
aggregates (latent silver specks) may precipitate along the particle's path.
2.2 The Action of Dislocations and Hole Traps
As already stated in part 1.2.2, the potential distribution around dislocations in
cadmium doped AgCl-crystals repels electrons but is attractive for holes. In this
way, electrons and holes are separated so preventing their undesired recombination.
This process is even promoted by the capture of holes at silver ion vacancies accumulated in the core of the dislocations (formation of V - c e n t e r s ) .
2.3 Electron Traps and the Track stabilizing Influence of a Simultaneous
Illumination
As schematically indicated in Fig. 3b, a (more or less) large fraction of electrons,
2
liberated by the ionizing particle, w i l l b e captured by solute C d + - ions,at the
interface between the precipitations of a cadmium-rich phase and the AgCl-matrix
or at clusters (or aggregates) of a small number of silver atoms. The latter, if
generated in regions outside the particle's path, compete with those formed along
its way and the total amount of silver produced by the ionizing particle is wasted
over a larger volume rather then being concentrated along the particle's path.
Therefore the passage of a fast moving ionizing particle, corresponding to a highintensity- short -time- illumination in terms of classic photography, generally leads
to a weak and unstable latent image of the track of the particle.
This
so-called "high intensity reciprocity failure" may be avoided if the detector
crystal is illuminated with inactinic light during or immediately after the passage
of the ionizing particle. Under the action of, say, red light, electrons are released
from small (unstable) silver aggregates, which are shallow traps for electrons, into
the conduction band (see Fig. 3 b ) . After some time, connected with their lifetimes,
the electrons may be retrapped and finally irreversibly captured in deeper traps
corresponding to larger(stable) silver aggregates.
Let us assume for simplicity that there exists a critical number n * of silver atoms
separating unstable (n<n*) from stable (n>n*) silver aggregates. Then the track
stabilizing growth of larger silver particles at the expense of smaller ones may be
Monocrystalline
described by the following
n<n*
Ag
A
W
+
red +
h v
AgCl-Detectors
53
"reaction":
A
W
"+ Ar gi
+
e
+ An
g -Krf
,+
^ i + 1 > n A*
#
A g
•
Such a redistribution from unstable small silver particles to large and stable silver
aggregates under the irradiation with n o n a c t i n i c
(e.g. red) light is well known
in classic photography as the "Positive Herschel"- or "Debot" - Effect. Its application to AgCl-crystal detectors gives the unique possibility to switch on and off
their response to ionizing particles.
3. IMPROVEMENT OF TRACK QUALITY BY PLASTIC
DEFORMATION
3.1 Spatial Correlation between Plastic Deformation and Track Quality
As first observed by Breuer and others (1967), tracks in the vicinity of scratches or
near indentations on the crystal surface seem to be more compact and more easily to
be decorated than in undeformed regions. Due to a systematic study on the influence
of crystal growth conditions and thermal treatment with respect to track detecting
properties of pure and doped AgCl-crystals by Wendnagel in 1979, it now seems well
established that residual plastic deformations improve the quality of the particle
tracks.
This is convincingly demonstrated in Fig. 4 where the diffuse shape of tracks in
undeformed regions changes to get very compact when approaching the plastically
deformed region near the scratch.
Fig. 4.
Tracks of 6 MeV - a HD:
UD:
0D:
particles. AgCl-detector doped with 20 ppm
heavily deformed region (scratch)
undeformed region
optimal deformed region with improved
track quality
cadmium.
54
Further evidence for an improvement of the detector quality by plastic deformation
may be drawn from Fig. 5. An annealed monocrystalline AgCl-foil (doped with 5000
EP2
cm
50
Fig. 5.
100*/. Thickness
Distribution of etch pits, i.e., dislocation density
along the cross section of a cold rolled AgCl-foil
ppm cadmium) of an original thickness of 150 urn, had been cold rolled down to a
final thickness of 100 um. The variation of the density of etch pits along a cross
section of the foil indicates an increase of about an order of magnitude in the dislocation density from the middle to the two outer surfaces of the foil. This is in
full agreement with observations that plastic deformation, caused by cold rolling,
decreases when proceeding from the surfaces to the middle of the foil. The dashed
curve in Fig. 5, indicating the quality of tracks in arbitrary marks (1=excellent
quality, ••• , 6=of no use) again shows the strong correlation between plastic deformation and track quality.
3.2 Ageing
Phenomena
In order to get a better understanding of the above observations, experiments were
performed — for more details see Wendnagel (1979) - where the quality of tracks was
studied as a function of the time passed between plastic deformation and exposure of
the detector to ionizing particles.
It turned out that the time intervall between plastic deformation and exposure must
at least be a few minutes in order to get an
improvement in track quality which finally reaches its saturation value after some days. If, on the other hand, the crystal
has been exposed to ionizing particles immediately after plastic deformation, the
quality of tracks changes for the worse in the deformed regions.
3.3 A Simple Model about the Influence of Plastic Deformation on Track Quality
The observed ageing of plastic deformation may again be interpreted in terms of the
interaction of dislocations with charged point defects and the formation of space
charges and of the corresponding potentials around dislocations. From the fundamental
theories of strain ageing, developed by Cottrell and Bilby (1951) and from a variety
Monocrystalline
AgCl-Detectors
55
of internal friction experiments performed with doped silver halide crystals, as
done by Kim and others (1974) and Horan and Slifkin (1979), i t follows that fresh
dislocations, introduced into a crystal, containing foreign atoms, by plastic deformation w i l l collect these impurities so that, after a certain time, each of the
fresh dislocations w i l l be surrounded by an atmospere of impurities.
2+
In the case of AgCl-crystals, doped with C d , the dislocation line w i l l pick up
negative silver
ion vacancies and the atmosphere around the dislocation w i l l con2+
s i s t of C d - ions forming the diffuse positive space charge already discussed in
part 1.2.2. Such a redistribution of point charges
by freshly introduced dislocations
3
follows a kinetics which corresponds to a t?^ -law, i f the i n i t i a l distribution of
impurities was homogeneous (as schematically sketched in Fig. 6a) and obeys a
law in the case of already existing Maxwell atmospheres around dislocations.
In each case, the range of diffusion i s given by:
14
x = /Dt .
2
Using a diffusivity of D = l o "
cm /sec (see Kim in 1974), the time t = t
,
needed for building up the space charge cloud around the dislocation, i s
of the order of a few days. In this case, x is taken to be half the distance
of
2
neighbouring dislocations, i . e . , 5000 S at a dislocation density of 10^/cm .
If, on the other hand, x i s set equal to the Debye - length of the charge cloud
(about 500 ft) the ageing time t =
drops to 40 minutes.
Depending on the thermal history of the detector crystals, the ageing times observed
by Wendnagel (1979)fit rather well into this time interval. On the basis of this
simple model, the influence of plastic deformation on the track quality can be interpreted as follows:
Immediately after the deformation, the freshly introduced uncharged dislocations
w i l l compete with the particle tracks. At this stage, the quality of the tracks
in deformed regions has changed to the worse with respect to tracks in undeformed ones.
After some ageing time, the point charges redistribute around the dislocations,
as sketched in Fig. 2b and Fig. 6b, and the resulting potential squeezes the
electrons between the dislocations leading there to highly compact tracks.
Thus, in order to further improve the quality of AgCl-detectors, care has to be
taken that the crystals, when leaving the furnace, s t i l l contain residual, homogeneous plastic deformations.
Fig. 6. Ageing of freshly introduced
dislocations.
56
REFERENCES
Baumgardt, H.G., J.U. Schott, Y. Sakamoto, E . Schopper, H. Stocker, J. Hofmann,
and W. Greiner (1975). Z. Phys., A 273, 359.
Breuer, K., G. Haase, and E . Schopper (1967). Brit. J. Appl. Phys., 18, 1824.
Cottrell, A.H., and B.A. Bilby (1951). Phil. Mag., 4 2 , 573.
Danyluk, S., and J.M. Blakely (1974). Surface Science, 4 1 , 359-370.
Fleischer, R.L. (1962). J. Appl. Phys., 33, 3504-3508.
Frank, W. (1967). Z. Naturforschung, 22a, 365-376.
Granzer, F., E . Schopper, K. Dardat, G. Henig, J.U. Schott, G. Haase, and F.Zorgiebel (1972). 8th Conf. N u c l . Phot, and V i s . Detectors (Bukarest 1972), 365-372.
Groeneveld, K.O. (1979). This conference.
Haase, G., E . Schopper, G. Henig, J.U. Schott, and F. Zorgiebel (1970).
Z. Angew. Phys., 30, 316.
Haase, G., F. Zorgiebel, E . Schopper, F. Granzer, G. Henig, J.U. Schott, and
Th. Wendnagel (1973). Photogr. S c i . Eng., 17, 409-412.
Haase, G., E . Schopper, and F. Granzer (1977). Radiation
Effects, 34, 25-31.
Horan, S.E., and L.M. Slifkin (1979). p h y s . stat. s o l . ( a ) , 51, 467 and
phys. stat. s o l . ( a ) , 51, 657.
Jin-Soon Kim, L. Slifkin, and A. Fukai (1974). J. P h y s . Chem. Solids, 35, 741.
Kanzaki, H., and S. Sakuragi (1973). Photogr. Sci. Eng., 17, 6 9 - 7 7 .
Kliewer, K.L. (1966). J. Phys. Chem. Solids, 27, 705-717.
Malinowski, J., and W . Platikanowa (1966). p h y s . stat. sol., 14, 205-214.
Schopper, E . , F. Granzer, G. Henig, J.U. Schott, K. Dardat, Th. Wendnagel, G. Haase,
and F. Zorgiebel (1972a). 8th Conf. N u c l . Phot, and V i s . Detectors,
(Bukarest, 1972), 350-364.
Schopper, E., and others (1972b). Proc. XV. Meeting Cospar (Madrid 1 9 7 2 ) .
Varley, J.H.O. (1954). Nature, 174, 886.
Wendnagel, Th. (1973). 3. DGKK - Jahrestagung, Hamburg.
Wendnagel, Th. (1979) . This conference.
Wentz, M., K. Ledjeff, K. Zierold, and F. Granzer (1976). J. Physique, 37,
Colloq. C 7 - 4 0 1 .
ACKNOWLEDGEMENT
This work was sponsored "by the German Ministry of Research and
Technology.
SUPRALINEARITY AND LET
DISCRIMINATION IN RADIATION
MEASUREMENTS
R. Katz, R. L. Rosman, A. S-F. Li and Y - L . Chang
University of Nebraska, Lincoln, NE 68588, U.S.A.
ABSTRACT
According to track theory, detectors whose response to gamma rays is
supralinear will inherently discriminate against low LET in favour
of high LET radiations, especially at low dose, while detectors
whose response is linear or exponential exhibit the reverse discrimination. The detailed characteristics of these discriminations can
be calculated once the radiosensitivity parameters of the detector
are known. If both one hit (exponential) and c-hit (supralinear)
detectors are exposed to the same radiation field, the complimentary
discriminations can be used to sort out the low and high LET components of the radiation field. An even more interesting discrimination may be possible. For if the detector parameters are appropriately chosen, they may be able to reflect the discriminations made
by biological tissue, for inactivation in the gamma kill mode (the
low LET response) and in the ion kill mode (the high LET response).
With nuclear emulsions it has been possible to choose emulsions and
develop them so as to obtain characteristically different response.
Some emulsions can be altered from 1-hit to 2-hit detectors by
varying the composition of the developer and the developing time.
To achieve a detector whose response parallels biological cells we
have sought a 2-hit response to X-rays of such a sensitivity that
single electrons do not make visible tracks, while single particles
do. With Ilford K-l emulsion we have achieved clean 2-hit response
at such sensitivity that a 5-5 MeV alpha particle makes 7-8 grains
developable. At slightly higher sensitivity the alpha particle
track consists of 11-13 grains, but there is a small component of
1-hit response, similar to that found in biological cells whose
survival curve displays an initial negative slope after gamma
irradiation.
Using computer simulations, we have estimated the radiosensitivity
parameters of these emulsions - developer combinations, have simulated the predicted track appearance of other particles, and have
calculated "survival curves" and "RBE's" of these materials after
irradiation with beams of ions of different composition.
57
58
R. Katz et at.
Detectors have different discriminating properties for high and low
LET radiation, depending on the values of their radios ens it ivity
parameters E Q and C. These are (l) the dose of gamma rays at which
there is an average of 1-hit per sensitive element and Xz) the
hitedness, nominally the number of electrons which must pass through
the sensitive target in order to activate it.
When absorbed dose is the basis of comparison, as in radiobiology or
in other integrating detectors, the 1-hit detector must always
yield a higher response to randomly deposited than to concentrated
energy depositions. Thus the 1-hit detector always discriminates
against high LET in favour of low LET radiations. Its response
is more nearly uniform to particles of all LET for the highest
values of E , for then, even close to the path of a heavy ion,
there is an insufficient local dose to saturate sensitive element
response. If the detecting elements are small molecules where E 0
is often quite high the response to gamma rays and high LET
radiations, say neutrons, is most nearly uniform.
These considerations have stimulated studies of the response of
alanine (measured by esr) to X-rays, neutrons, and helium ions, made
with F, Bermann, with results consistent with these perspectives.
The response of 1-hit detectors to X-rays is a saturating exponential, linear at low dose and sublinear at high dose. With such
detectors the only discrimination that can be achieved is by variation of E Q .
We now know that the variation of E in 1-hit nuclear emulsions
ranges over a factor approaching 1000. When translated into the
structure of particle tracks (and ignoring problems of background,
fading, and the kinematic limitation on delta ray energy) track
segments of identical
appearance
can be produced in different
B
or
emulsions, (Z» eff/ )^ ^
these particles differs by a factor
approaching 1000, as between K-5 and K-l emulsions, differently
developed.
In the grain count regime, measurements of grain count can be made
with reasonable comfort over a range of factor 10, say, from 15 to
150 grains/100 microns.t This means that in a single emulsion only
a factor of 10 in (2/B)^ can be accommodated by this technique,
but that the useable range of this parameter over which grain
count measurements can be made can be extended by several hundred
times, by suitable choice of emulsion-development regimes, designed
for the particular experimental problems.
The situation is quite different from many hit detectors. Here
the transition from dispersed grains to a solid track takes place
in a narrower interval of (Z/B)2, for the grain density varies
nominally as (Z2/B2)C? where c is the hittedness. Thus if a sharp
discrimination is desired, but with a narrow window, one can go to
c-hit emulsions.
Our efforts in these researches have been directed toward the production of 2-hit response at the lowest possible value of E Q . We
ask the question as to what is the transition region such
that
an emulsion passes from a 2-hit to a 1-hit detector. In part this
Supralinearity and LET Discrimination
59
depends on the homogeneity of grain size distribution, and on grain
size itself.
We have worked with Ilford K-l emulsion using blackness-exposure
curves after X-rays to determine the hittedness, and alpha particle
tracks, in conjunction with track theory and hittedness to determine
In this emulsion different developments produce (A) 1-hit detection
with E 0=1.2 x 10' erg/cnP, (B) a supralinear response fitted by no
obvious model, (C) a supralinear response well fitted by the radiobiological alpha-beta model, and (D) a 2-hit response with E 0=1.7 x
10' erg/ciiK. Tracks of alpha particles in these emulsions coded by
the letters A, B, C, and D are shown in Fig. 1.
In Figs. 2 and 3 we show computer simulations of sections of tracks
of Z=l, 2, 3, 5, and 10 ions in 1- and 2-hit emulsions for which
E Q=1.5 x 10' erg/cm3, for comparison with the alpha particle tracks.
These computer generated tracks are shown for particles coming from
the right and stopping at left. Shown are 100 micron sections from
900 - 1000 microns and from 400 - 500 microns of residual range,
and that left the stopping 200 microns of the track. There is a
large difference between the response of a 1-hit and 2-hit detector
in the rate of increase of grain density as a function of range.
For comparison we show in Figs. 4 and 5 for an emulsion 10 times
more sensitive, for which E 0-1.5 x 10° erg/cm^.
To compare the response of emulsion detectors to radiobiology,
it is useful to display calculated curves of the logarithm of the
probability K for killing cells or for making grains developable
as a function of the fluence of beam of different particles. In
Fig. 6 we display as top and bottom panels the calculated curves
for 2-hit emulsion of different sensitivity, as in Figs. 3 and 5,
and in the centra], panel calculated curve for T-l human kidney cells.
The bombardments are for (Z,B)=(18, 0.12), (7, 0.12), (2, 0.12),
(2, 0.25), (2, 0.50) and (l, 0.99), which are characteristic of a
range from high to low LET, used in radiobiology.
There is a transition in the shape of these curves, from supralinear
at right,low LET, to linear at left, at high LET. At intermediate
values of LET, the curves are linear at low dose and supralinear at
high dose. These changes are associated with the increase of the
importance of the ion kill mode of inactivation with an increase in
LET. We must remember that these emulsions curves are calculated
rather than measured and are presently part of an experiment design
for subsequent test.
If we are to have an emulsion useful in dosimetry, which has the
same sort of discrimination against low LET radiations that we find
in mammalian cells, it appears that we must have an emulsion of
somewhat lower E 0 than we have presently achieved, perhaps by
factor 3.
From Figs. 3 and 5 such an emulsion should give grains at the very
end of a proton track as well as a stronger signal from an alpha
particle than we have presently obtained. This should give a
60
R. Katz et
al.
response to neutron secondaries rather like the response of biological cells while discriminating against gamma rays. The goal
seems achievable. We can imagine, at least, that 2 sheets of
K-l emulsion exposed to the same neutron field can be differently
developed so that one of these sheets is a 1-hit detector which
discriminates in favour of gamma rays, while the other is a 2-hit
detector which discriminates in favour of neutrons. We would be
able to measure directly the gamma ray component and the neutron
component of a neutron field by measuring emulsion blackness alone.
Additionally the discriminatinns available by varying E Q and c
in the measurement of particle tracks can be expected to open new
applications of emulsions in the field of heavy ion research. No
recipes are available for the best design of such detectors. We
know nothing about fading or about the control that must be
exercised to achieve consistent results. We know only that a new
class of emulsion response is possible.
ACKNOWLEDGEMENTS
We thank Joanne Motycka for her assistance.
These investigations were supported by the United States Department
of Energy and the International Atomic Energy Agency.
Supralinearity and LET
ALPHA
Discrimination
PARTICLES
IN K-l
EMULSION
B
D
0
I
I
I
pm
Fig. 1
I
I
50
61
0^
C =1
E =1.5x10 ergs/cm
7
3
o
Residual Range (pm)
0
1
1
-
-
900
I I
.
...
z^vy. -H
2
3
"IP
7
400
I I
5
10
i
0
i
i
50
i
i
100 p m
Fig. 2
E =1.5x10 ergs/cm
0
(um)
Range
Residual
3
7
C=2
o
o
CD
O
O
0
i
_
CO
Supralinearity and LET
CM
Discrimination
i n
T—
o
E
ZL
o
- o
-O
CO
bD
•H
63
64
C =1
Eo=1.5 x 1 0 e r g s / c m
6
3
Residual Range ( p m )
0
400
1
I
I
900
I I
2 1
R. Katz et
2
al.
3
5
10
i
0
i
i
50
i
i
100
pm
Fig.
4
C=2
E =1.5x10 ergs/cm
6
Residual Range
0
( urn )
400
i
1
900
.
i
Supralinearity and LET Discrimination
Z
3
o
2
3
5
10
i
o
i
50
i
i
100 Mm
Fig. 5
5
R. Katz et al.
66
10
v
'LATENT IMAGE'" CREATION
VS FLUENCE
10
K
10'
7
E=l.5XI0 ergs/cm
3
A-I.ZXIC^cm
10"
10'"
10
2
FLUENCE (particles/cm )
lot-
CELL KILLING VS FLUENCE
T-l H U M A N
(TODD
KIDNEY
CELLS
N 2)
ion
K
10"
(18,0.12)
(1,0.99)/
4
E = l.7XI0 ergs/cm
2
m=2.5
k =1000
,
cr=6.7XI0 c m °
Beam:(Z,/3)
10°
10^
10^
10°
10'
8
10'
2
I0~
10
10'
I0
V
"LATENT IMAGE' CREATION VS FLUENCE
10
1
K
10r2
6
3
10 ergs /cm
10"
10^
I0
2
Fig.
6
,v
CONNAISSANCES ACTUELLES SUR LES
ACETATES DE CELLULOSE EN T A N T
QUE DETECTEURS SOLIDES
DE TRACES
J. P. Moliton*, C. Boutinaud*, J-L. Decossas*, J. C. Vareille*,
J-L. Teyssier* et B. Delaunay**
* Laboratoire des Radiations Ionisantes, 123 rue A. Thomes,
87060 Limoges, France
**C.E.A. Saclay, 91190 Gif-sur-Yvette, France
ABSTRACT
Apres un rappel des connaissances actuelles sur les proprietes des acetates de
cellulose en tant que detecteurs de traces d'ions lourds, nous abordons 1'etude generale de leur endomagement. Les spectroscopies d'absorption UV et IR permettent
de determiner les volumes dans lesquels sont detruits les groupes CO et sont formes des radicaux libres. Pour la premiere fois, les reactions de premiere espece
sont etudiees; elles se manifestent essentiellement dans le cas du triacetate par
la formation de ponts hydrogenes, de CO^ et d'alcools primaires et secondaires.
KEYWORDS
Traces reveles. Radicaux libres. Trace latente. Reactions de 1° espece
ASPECT TRACES INDIVIDUELLES
Introduction Les acetates de cellulose sont reconnus comme des detecteurs solides
de traces (DST) des le debut des recherchesdans ce domaine. Debeauvais et Monnin
(1965) signalent que le Triafol T (triacetate Bayer) a un seuil d'enregistrement
qui correspond a des particules dont le transfert d'energie 1ineique(TEL) est de
150 keV/ym. Au cours des annees qui suivent, les acetates sont cites comme detecteurs sans qu'une etude systematique soit entreprise. Les efforts portent principalement sur le nitrate de cellulose qui est apparu tres vite comme le plus sensible
des detecteurs. De plus, les acetates etudies sont de provenances diverses(triafol,
triacel, cellit,...) ce qui interdit toute comparaison rigoureuse entre les resultats des differents auteurs. Signalons les travaux de Johnson, Boyett et Becker(1968)
qui abordent sur differents plastiques (nitrate et acetate) une etude de la formation de la trace latente qui prefigurent les resultats que nous evoquons dans la
suite de cet expose.
Seuil de detection Tres tot Somogyi(1968) puis Varnagy(1970) ont signlale l'enregistrement possible de protons dans le triacetate de cellulose, ce qui implique un
abaissement de la limite d'enregistrement intr duite par Debeauvais. Ce resultat
est interessant. En effet on recherche a caracteriser un materiau detecteur par la
donnee de I'ion le plus leger enregistre a une eivrgie donnee puis a relier, en
premiere approximation, la sensibilite du detecteur, dans des conditions experimentales donnees, a un TEL critique
(TEL ). L'existence d'un TEL n'est evidemment
1
pas etrangere aux phenomenes d interaction ion-matiere a l'echelle moleculaire,
ce qui accroit l'interet de la determination pour un detecteur de son TEL.Dans une
S.S.N.T.D. — D
67
J. P. Moliton et al.
68
etude recente, Decossas et ses co-auteurs (1979) ont montre que le triacetate de
cellulose (T.A.C.) fabrique au laboratoire dans certaines conditions de revelation,
a un (T.E.L)
inferieur ou egal a 50 keV/ym.
Selon le degre de substitution, on distingue dans les acetates de cellulose : le
diacetate (D.A.C.), le triacetate ( T . A . C . ) . Les reponses aux ions lourds de ces
deux plastiques, de composition semblable, different de facon notable comme nous
I'avons note a Munich (Decossas et ses co-auteurs 1 9 7 6 ) . Alors que le T.A.C. a,
avec les protons un (T.E.L)
de 50 keV/ym, le D.A.C. n'enregistre pas d'ion plus
leger que l'oxygene ce qui correspond a un (T.E.L)
de 800 keV/ym (revelation p o C
tasse KOH 0,9 N - 2 0 ° C ) .
1
Etudes en Vue d Applications
1
Un certain nombre d e t u d e s sur les acetates de cellulose ont ete entreprises pour
d'eventuelles applications (exemple : detection des neutrons par Kenawy et ses coauteurs (1976) ) . II s'agit essentiellement de bien maitriser les conditions de revelations : nature, concentration, temperature de 1'agent chimique. Citons a titre
1
d e x e m p l e et sans etre exhaustif : Blandford, Walker, Wefel (1968) ; Somogyi, Varnagyi, Medveczky (1968) ; Vareille, Teyssier (1972)... Ces etudes peuvent etre v a rices a l'infini du revelateur sophistique, a la concentration ad'hoc avec temperature ideale... Bien sur dans le cadre restreint d'une application il ne faut pas
meconnaitre l'interet de telles recherches, mais il convient d'admettre que ces resultats ne permettent pas d'acceder a des lois generales. On retiendra peut etre
que l'on a interet a travailler a la temperature de revelation la plus basse p o s sible, ce qui a pour effet d'augmenter le rapport d'attaque chimique
defini par:
_ _T
v
: vitesse d'attaque le long de la trace
: v V: t e e
s s
n r a e
T
v^
g
*g s ^ l d'attaque du materiau
Etudes systematiques
La grandeur
est,en effet, commode dans la mesure ou elle permet de caracteriser
1
les proprietes d e n r e g i s t r e m e n t et de revelation des traces dans un materiau. C'est
elle que nous avons choisie dans notre laboratoire pour examiner 1'influence sur
la reponse d'un D.S.T. du T.E.L, de l'humidite, de l'oxygene, du plastifiant, des
conditions thermiques de stockage avant et apres irradiation, d'une preirradiation
par photons y. Nous citons nos resultats (Vareille et ses co-auteurs 1 9 7 5 ) . Ce sort
evidemment ceux que nous connaissons le mieux, mais d'autres auteurs ont aborde,
parfois plus en detail, ces etudes enrichies de l'influence des U.V. etc... Nous
indiquerons, la aussi tres parteillement : Nicolae (1972), chauffage avant irradiation, influence des U.V. et des photons y ; Marchetti, Tommasino, Casnati (1972),
traitement thermique avant et apres irradiation ; Somogyi (1972), effet de l'ozone,
effet thermique. Dans ce domaine nous ne noterons que quelques
resultats.
L'influence primordiale de la constitution du materiau est mise en evidence en
faisant varier la concentration en plastifiant. Par exemple pour des ions Argon,
1'evolution de R^ en fonction du pourcentage en plastifiant du T.A.C. est donnee
dans le tableau
1.
Tableau 1 Evolution de R
en fonction du pourcentage en plastifiant
Plastique
sans plastifiant
5 % plastifiant
20 % plastifiant
126 ± 5
230 ± 5
254 ± 5
Pour tenter de modifier le sensibilite du detecteur, nous avons effectue une p r e irradiation par des photons y, qui conduit a une diminution importante de R^ (fig.l)
De meme 1'influence de 1'atmosphere au cours de 1'irradiation est nettement m a r quee comme l'illustre la fig. 2 dans le cas d'irradiation sous oxygene, air et
azote (Vareille 1 9 7 2 ) .
Connaissances
69
A c t u e l l e s
4
3'
SO
F i g .
1
V a r i a t i o n
dose
de
de
R^
en
photons
f o n c t i o n
de
l a
F i g .
2
y
de
1
L
SUR
t i b l e
de
de
1
i n t e r a c t i o n
mieux
de
des
t r a c e s
obtenus,
a.
des
i n d i c a t i o n s
p h y s i q u e ,
a f i n
q u i
au
Dans
l ' e c h a n g e
p r i m a i r e "
temps,
.
miere
peu
a c t i o n s
.
des
deposee
.
que
des
ces
de
e n f i n ,
de
echanges
du
pour
des
d i f f e r e n t e s
pour
t r a c e s
i r r a d i a -
atmospheres
T r i a c e t a t e
de
C e l l u l o s e
T . A . C .
un
t r i e s t e r
e s t
La
1 ' a u t r e ,
T . A . C .
l u l o s e
a
64
s e i n
e t
p e u t
du
p u i s q u ' e l l e
e s t
a u s s i
pnrcco^-
f o u r n i r
d e t e c t e u r
p a r
1 ' o b s e r v a t i o n
un
p r o c e -
i n d i v i d u e l l e
l ' e s s e n t i e l
des
r e s u l t a t s
d i s t i n g u e r
l ' " e n e r g i e
f
l " e n e r g i e
:
on
p e u t
d i r e c t e m e n t
Le
p a r
l ' i o n
processus
e t
d ' e v o l u t i o n
au
cours
de
p r e -
:
m a t e r i a u
en
e n t r e
que
deux
l ' i o n
l ' o n
a p p e l l e
p a r t i e s
e t
l a
:
:
" r e a c t i o n
d ' a b o r d
m a t i e r e ,
l a
f o r m a t i o n
e n s u i t e
l e s
des
i n t e r -
ambiant
l e s
( a i r ,
c o n s t i t u e
rayons
l e s
" r e a c t i o n s
U . V . ,
e t c . . )
" r e a c t i o n s
de
3eme
Le
schema
sur
l e s
p r o d u i t s
au
d e v e l o p -
s e c o n d a i r e s " .
espece"
corespondent
c h i m i q u e .
Le
3-
e l l e
e l l e
p r o d u i t s .
espece
memoire,
l e
fondamental
mais
d ' i n d i q u e r
m a t i e r e ,
deposee
s u b d i v i s e r
m i l i e u
p r e m i e r e
au
s e c o n d a i r e s .
d ' e n e r g i e
d i f f e r e n t s
l a
ou
chimique
Avant
phases
avec
p e u t
Le
F i g .
t r o i s
mesure
d e f i n i t i o n s
e l e c t r o n s
en
l ' i o n
l ' o n
1 ' i n t e r v e n t i o n
r e a c t i o n s
pement
e t
i s s u s
e n t r e
d ' e m p l o i .
quelques
l e s
c a r a c t e r e
d ' i n t e r v e n i r
1
e t
e n t r e
I i o n
1
e t
d i o n i s a t i o n ,
separe
un
l a
developpement
commodes
p a r
e t r e
1 ' i n t e r a c t i o n
p r o d u i t s
maniere
l e
a
d'endommagement
dans
d ' e n e r g i e
p e u t
espece"
l a
p r e a l a b l e
d ' e x c i t a t i o n
s e c o n d a i r e "
du
m a t i e r e
mecanismes
a p p l i c a t i o n s
sur
D e f i n i t i o n s
63
a
des
1
D ENDOMMAGEMENT
PROCESSUS
l o u r d
l e s
d ' e v i t e r
sont
voi.ci
i o n
c o n n a i t r e
c o n d u i r e
des
de
de
sous
2oo
ISO
d i a m e t r e
1
e t u d e
permet
a
LES
du
p a r t i c u l e s
t i o n s
GENERALITES
I0O
E v o l u t i o n
d i s p o s i t i o n
d'ou.
que
a
u t i l i s o n s
93
l a
c e l l u l o s e .
r e l a t i v e
1 ' e x i s t e n c e
nous
a c e t y l e e
( T . A . C . )
de
% au
de
des
chaines
zones
sont
moins
de
c r i s t a l l i n i t e
amorphes
e t
p a r
de
a.
95
D.A. C.
%.
une
On
3
Sequence
dans
l e
m o l e c u l e
p e u t
e s t
changer
r e p r e s e n t s
d'une
d i f f e r e n t e .
Les
d e s i g n e
T . A . C .
c e l l u l o s e
%.
F i g .
l a
c e l l u l o s i q u e s
T . A . C .
p a r
a c e t y l e e
r e g i o n
e c h a n t i l l o n s
aux
une
c e l -
e n v i r o n s
de
70
ETUDE DES ENDOMMAGEMENTS DE 2eme ESPECE
Aspect Qualitatif
L'action des ions lourds sur le T.A.C. se manifeste essentiellement par la rupture
des 3 types de liaisons C-0 represented sur la figure 4.
C
Fig. 4 Les 3 types de rupture de liaison C-0 dans le T.A.C. apres actions des
ions lourds
On peut dire que :
A correspond a un fractionn§ment de la chaine cellulosique
B represente l'ouverture du cycle pyrannosique
C est une deacetylation
Ce resultat a ete obtenu par 1'observation a 20°C dans l'air ambiant du spectre
infrarouge du T.A.C. (Moliton 1 9 7 4 ) . Sur la figure 5 sont indiques le spectre I.R.,
1
1 identification et le comportement des bandes d'absorption en fonction de la fluence en ions lourds.
4000
3000
1
Bande cm"
Identificatior
Comportement
'
\\\\
2000
296 0
17 50
'
1600
14 3 0
13 70
X
1320
1200
'
1 22 0 M 1 1 6 2
6(CH 2)V (C-0) c-o-c
6 (OH)
V(0-H ^(C-H) V (C=0) 6(0*3)
X
'
X
800
948
type 1
des
sucres
'
899
1
<T ( c m * )
8 72
1 type2
6(CH2 des
200
600
Non
ident.
sucres
X
Fig. 5 Spectre I.R. d'un film de T.A.C. avant et apres irradiation en ions
(1,1 MeV/u.m.a.) avec le comportement des bandes d'absorption
X
Kr
Le comportement du D.A.C. est assez different. Alors qu'en fonction de la fluence
le nombre de liaisons (0-H) augmente dans le T.A.C., il diminue dans le D.A.C. De
plus, l'ouverture du cycle pyrannosique et de la liaison acetal C . . -O . -C .,. se
Connaissances
p r o d u i s e n t p o u r des f l u e n c e s n e t t e m e n t p l u s
1976) .
Actuelles
71
f a i b l e s que dans l e T . A . C .
(Decossas
P r i n c i p e des E t u d e s Q u a n t i t a t i v e s
La s p e c t r o s c o p i e I.R. a f a i t a p p a r a i t r e des
r u p t u r e s de l i a i s o n s C - 0 . Des t r a v a u x
a n t e r i e u r s s u r l ' e f f e t des r a d i a t i o n s , notamment des p h o t o n s U . V . , s u r l a c e l l u l o s e
e t ses d e r i v e s m o n t r e n t q u ' i l y a p r o d u c t i o n de r a d i c a u x l i b r e s ( c f t a b l e a u 2 H o n ,
(1975) .
TABLEAU 2 O r d r e de s t a b i l i t e
•
Si
•a^ <
C 1 )
\
des r a d i c a u x
dans l a c e l l u l o s e
1
Vir <V
( c5) —
libres
/
RC-
\ " S / c ( -1)
_ c
n c l Rcr./
«
Yes*
/WX^)
(Hon,
1975)
<r^. \ « °
ch
E t a n t donne que D e f f n e r ( 1 9 7 2 ) a m o n t r e que l e s p h o t o n s y c r e e n t eux a u s s i des r a d i c a u x l i b r e s dans l e T . A . C . e t que Chambaudet ( 1 9 7 7 ) a p r o u v e 1 ' e x i s t e n c e e g a l e ment de r a d i c a u x l i b r e s dans d ' a u t r e s d e t e c t e u r s comme l e p o l y m e t h a c r y l a t e de met h y l e ( P . M . M . A . ) , o n p e u t p e n s e r , comme B o y e t t ( 1 9 7 0 ) , que l e s i o n s l o u r d s c r e e n t
des r a d i c a u x l i b r e s dans l e T . A . C . P a r une methode s i m i l a i r e a c e1l l e de B o y e t t ,
( u t i l i s a t i o n de l a t e c h n i q u e du " s c a v e n g e r " ) , nous avons e t u d i e l e v o l u t i o n du n o mbre de r a d i c a u x l i b r e s en f o n c t i o n de l a f l u e n c e en i o n s . P a r a l l e l e m e n t nous avons
examine q u a n t i t a t i v e m e n t l a d i m i n u t i o n du nombre de l i a i s o n s C - 0 . L ' e t u d e des r a d i caux l i b r e s s ' e f f e c t u e p a r 1 ' o b s e r v a t i o n dans l e domaine U . V . de l a bande l a p l u s
i n t e n s e du D P P H u t i l i s e comme " s c a v e n g e r " , q u i d e c r o i t l o r s q u e l a f l u e n c e a u g m e n t e , l e r a d i c a l l i b r e d u ' s c a v e n g e r " se c o m b i n a n t a v e c l e s r a d i c a u x l i b r e s c e l l u l o s i q u e s . L ' e t u d e du t a u x de d 1e s t r u c t i o n des l i a i s o n s C - 0 se f a i t p a r 1 ' o b s e r v a t i o n de l ' i n t e n s i t e des bandes d a b s o r p t i o n du s p e c t r e I.R. du T . A . C . S i l ' o n d e s i gne p a r : N l a f l u e n c e
2
V l e volume i r r a d i e de s e c t i o n 1 cm n o r m a l e a l a t r a j e c t o i r e de l ' i o n
v . l e volume endommage p a r un i o n e t V ( N ) c e l u i endommage p a r N i o n s
n
l a c o n c e n t r a t i o n en espece e t u d i e e ( r a d . l i b r e , l i a i s o n C - 0 ) a v a n t
irradiation
n
l a c o n c e n t r a t i o n en espece e t u d i e e ( r a d . l i b r e , l i a i s o n C - 0 ) a p r e s
irradiation
Des c a l c u l s s t a t i s t i q u e s m o n t r e n t que
soit
Comme l a s p e c t r o s c o p i e
U.V.
fournit
experimentalement
l e terme L =
(1 - ^ - )
rela-
t i f aux r a d i c a u x l i b r e s , e t que l a s p e c t r o s c o p i e I.R. d o n n e , e l l e , d i r e c t e m e n t ^ — = L
en f o n c t i o n de l a f l u e n c e , on p e u t c a l c u l e r l e volume v ^ . En a d m e t t a n t que ce
o
volume e s t c e l u i d ' u n c y l i n d r e de h a u t e u r e g a l e a u p a r c o u r s de l ' i o n , on o b t i e n t
l a v a l e u r du r a y o n d*endommagement s u i v a n t l a n a t u r e du d o m m a g e . ( C ' e s t en f a i t une
e s t i m a t i o n de l a d i m e n s i o n
â t r a c e l a t e n t e ) . La f i g u r e 6 r e p r e s e n t e l e modele
a i n s i obt^gu gy^c des i o n s
Kr
( 1 , 1 M e V / u . m . a . ) . Pour i n f o r m a t i o n , s i g n a l o n s que
les ions
CI
( 1 M e V / u . m . a . ) o n t un c y l i n d r e de p r o d u c t i o n e n r a d i c a u x l i b r e s
beaucoup p l u s e t r o i t p u i s q u e l e r a y o n e s t s e u l e m e n t de 8 0 A c o n t r e 2 5 0 A aux K r .
72
J .
F i g .
6
Modele
de
EFFETS
J u s q u ' a
p r e s e n t
en
l o u r d s ,
ions
i n t e r e s s e
a
l a
l a
DE
NON
1 ' e f f e t
c'est
a
en
n
c o n c e n t r a t i o n
l a
o
ions
N
l a
f l u e n c e
N
l e
d e b i t
£
N
—
=
en
s i
u
q u e s t i o n
n e l l e
a
l a
c i d e n t s ,
du
de
en
de
depot
a
( 1 , l M e V / u . m . a . )
dans
l e
T . A . C .
comme
e t e
e t u d i e
d ' e n e r g i e
c ' e s t
a
d i r e
precedemment
espece
f o n c t i o n
de
l ' i n f l u e n c e
p a r
l a
Personne
du
f l u e n c e
1
s
e s t
ne
d e b i t
de
:
e t u d i e e
de
donne
en
a p p o r t e e .
c e t t e
p a r
meirie
u n i t e
espece
de
volume
ions
f l u e n c e
m a i n t e n u
D ' a u t r e
-
—
v
en
un i n s t a n t
v
:
at.
Kr
a
q u a n t i t e
i r r a d i a t i o n
l a
s o i t
et
i o n
d ' e n e r g i e ,
Designons
r reeppr re es se g. nn t e
=
l a
i n i t i a l e
d ' i o n s
d ' u n
1'endommagement
apres
nombre
l e
=
M o l i t o n
LINEARITE
de
l o u r d s .
"
5
l a t e n t e
d i r e
v i t e s s e
f l u e n c e
n
t r a c e
P.
=
n
X
v i t e s s e
n
de
E, o u
c o n s t a n t
de
p a r t
on
e s t
de
que
c e t t e
de
l a
c o n s t a n t e .
I l
v i e n t
-X
1'espece
d i s p a r i t i o n de
de
e t
_
On
1 ' i r r a d i a t i o n .
v i t e s s e
e c r i r e
e t u d i e e
une
n
cours
La
p e u t
1'espece
X
au
1 ' i o n .
v i t e s s e
e s t
a l o r s
£
p r o p o r t i o n en
ions
i n -
:
N
u
n
On
o b t i e n t
p a r
l e
une
c a l c u l
v a r i a t i o n s
l a
f i g u r e
noyau
du
7
l o i
de
d e c r o i s s a n c e
s t a t i s t i q u e .
r a p p o r t
sur
—
l a q u e l l e
0
Le
en
e x p o n e n t i e l l e ,
d e b i t
de
f o n c t i o n
sont
f l u e n c e
de
N.
Or
r e p r e s e n t e e s
comme
nous
ne
p a r a i t
i l
n ' e n
l e s
pas
n ' e s t
v a r i a t i o n s
l ' a v i o n s
d e j a
t r o u v e
i n t e r v e n i r
dans
r i e n
comme
l e
dans
l e
de
L(N)
l e s
montre
cas
du
p y r a n n o s i q u e .
Une
e x p l i c a t i o n
pose
en
que
l a
f o n c t i o n
v
e t a n t
p e u t
de
depend
£
e t
ne
t r o u v e e ,
v
v a r i e
de
s i
pas
£
l ' o n
sup-
l i n e a i r e m e n t
,
s o i t
:
2
= X'
n
£
=
t o u j o u r s
r a d i a t i o n ,
e t r e
v i t e s s e
l e
une
c o n s t a n t e
r a p p o r t
au
d e v i e n t
IL_
cours
de
1 ' i r -
:
ions/ern\s
F i g .
Le
1
E f f e t
courbe
f o n c t i o n
n e n t
de
du
de
non
l a
f i g u r e
d e b i t
e f f e c t i v e m e n t
l i n e a r i t e
de
un
5
s ' i n t e r p r e t e
f l u e n c e
N.
Les
c o e f f i c i e n t
de
done
c a l c u l s
comme
p a r
c o r r e l a t i o n
une
l a
e x p o n e n t i e l l e
methode
t r e s
des
v o i s i n
de
d e c r o i s s a n t e
moindres
1 .
c a r r e s
en
don-
Connaissance
Actuelles
73
ETUDE DES REACTIONS DE l e r e e t 2 erne ESPECE
I I s ' a g i t l a de r e s u l t a t s e n t i e r e m e n t n o u v e a u x . L e s i r r a d i a t i o n s a - 160°C e t l ' a n a l y s e des dommages p a r s p e c t r o s c o p i e I . R . a - 125°C o n t n e c e s s i t e l a m i s e a u p o i n t
d'un c r y o s t a t e t d'une c e l l u l e I . R . jumeles, d'une conception entierement originalg_.
4
Nous nous c o n t e n t o n s de d o n n e r 4 l o' e1s +3s e n t i e l d e s r e s u l t a t s o b t e n u s a v e c d e s i o n s ^ K r
( 1 , 1 M e V / u . m . a . ) e t des i o n s
Ar
( 6 , 5 MeViu.m.a.).
P r o d u i t s de l e r e Espece
A b a s s e t e m p e r a t u r e , l e s r e c o m b i n a i s o n s d e s p r o d u i t s d i r e c t s de 1 ' i n t e r a c t i o n i o n
m a t i e r e se t r o u v e n t , p o u r l a p l u p a r t , b l o q u e e s . Dans l e c a s du T . A . C , 1 ' i r r a d i a t i o n
p r o v o q u e 3 t y p e s de phenomenes ( f i g . a ) :
- l a f o r m a t i o n de l i a i s o n s du t y p e p o n t - h y d r o g e n e a v e c 1 ' a p p a r i t i o n d ' u n e p a u l e m e n t t r e s marque a 3 3 0 0 c m " ^ .
- l a f o r m a t i o n de C O 2 q u i a - 125°C e s t c r i s t a l l i s e , a v e c l e s deux bandes a
2234 e t 2 2 7 0 c m ~ * . Ces deux bandes o n t e t e o b s e r v e e s p a r O s b e r g ( 1 9 5 2 ) a v e c du CO2
a - 190°C.
- l a f o r m a t i o n d ' a l c o o l s , p r i m a i r ^ s a v e c l a bande v(RCH2~0H) a 1 2 5 7 cm~^, e t
s e c o n d a i r e s a v e c l a bande v(RCH-OH) a 1082 c m " ^ , l a bande 6 ( 0 - H ) dans l e p l a n a
1015 cm"^ se r a t t a c h a n t a l ' u n de c e s a l c o o l s .
Fig.
8
P r o d u i t s de l e r e e s p e c e dans l e T . A . C .
Dans l e c a s d u D . A . C . i l y a de l a meme f a c o n f o r m a t i o n de l i a i s o n s h y d r o g e n e , m a i s
en p l u s f a i b l e q u a n t i t e , de CO2, e t d ' a l c o o l s p r i m a i r e s , m a i s p a s d ' a l c o o l s s e c o n d a i r e s . L a bande 6 ( 0 - H ) a 1015 cm"^ n ' e x i s t e p a s non p l u s . E l l e s e r a i t done a r a t t a c h e r a u b a l a n c e m e n t 0 - H dans l e s a l c o o l s s e c o n d a i r e s .
R e a c t i o n s de R e c o m b i n a i s o n d e s P r o d u i t s de l e r e Espece
Pour p r o v o q u e r c e s r e c o m b i n a i s o n s nous avons p r o c e d e a une r e m o n t e e e n t e m p e r a t u r e ,
j u s q u ' a + 3 5 ° C , t o u j o u r s sous v i d e . Dans l e c a s du T . A . C . on n o t e l a d i s p a r i t i o n
des l i a i s o n s h y d r o g e n e a i n s i que c e l l e du g a z c a r b o n i q u e q u i s ' e s t v a p o r i s e dans
l a c e l l u l e . L e s a l c o o l s s o n t r e s t e s s t a b l e s . En ce q u i c o n c e r n e l e D . A . C . , l e s p o n t s
h y d r o g e n e q u i e x i s t e n t >'
. t i r r a d i a t i o n (bande a 3 3 5 0 c m ~ l ) e t q u i c o n t i n u e n t d ' e x i s t e r a f r o i d apres i n
. i a t i o n tendent a d i s p a r a i t r e . Par c o n t r e , l e s alcools s e c o n d a i r e s a p p a r a i s s e n t a 1082 c m * . Ce q u i n ' e t a i t done a u d e p a r t que d e s l i a i s o n s
h y d r o g e n e , du f a i t de 1 ' a c t i v a t i o n a p p o r t e e p a r l a t e m p e r a t u r e d e v i e n t une f o n c t i o n
a l c o o l s e c o n d a i r e . L e so p uo nvttsa hndy dor or g
e n e e x i s t a n t a u n a t u r e l s e r a i e n t done s i t u e s e n
n n e
C
ne
P
qu'un a l c o o l p r i m a i r e .
C^|Ou C ^ j , (6)
R e a c t i o n s de 2eme Espece
E l l e s s o n t o b t e n u e s p a r une e n t r e e d ' a i r dans l a c e l l u l e d ' a n a l y s e
I.R.L'analyse
t o u j o u r s a + 35°C a l i e u 48 h e u r e s a p r e s . Que ce s o i t p o u1r l e D . A . C ou p o u r l e
T . A . C , i l y a r e s s e r e m e n t de l a bande V ( O - H ) a 3 5 0 0 c m " , ce q u i semble m o n t r e r
74
que les quelques pontages 0
H restant sont definitivement partis. Les alcools
primaires, comme secondaires ont eux aussi egalement disparu. Signalons que
Chambaudet (1977) avait deja observe a la temperature de 1'azote liquide 1'existence de C02 dans du kapton irradie par des ions argon de 7 MeV/u.m.a.
REMERCIEMENTS
Nous tenons a. remercier tres vivement les equipes du C.E.V. d'Orsay ou ont eu
lieu 1'ensemble des irradiations a basse temperature.
REFERENCES
Blandford, G.E., R.M. Walker, and J.P. Wefel (1969). Compte-Rendu Jourentra
Clermont-Ferrand, 111-27.
Boyett R.M., Johnson D.R. and Becker K. (1970). Rad. Res., 42, 1.
Chambaudet A. (1977). These Universite Pierre et Marie Curie (Paris V I ) .
Debeauvais M. and M. Monnin (1965). C.R. Acad. Sci. Paris 260, 4728-4730.
Decossas J.L., J.P. Moliton, J.C. Vareille, J.L. Teyssier, and B. Delaunay (1977).
Rad. Effect., 34, 61-65.
Decossas J.L., J.P. Moliton, J.C. Vareille, J.L. Teyssier, and B. Delaunay.
A paraitre.
Deffner U., and H. Paretzke (1972). Rad. Res., 49, 272.
Hon N . S . (1975). J. Polym. Sci., 13, 2653.
Johnson D.R., R.H. Boyett, and K. Becker (1969). Compte-Rendu Jourentra, ClermontFerrand, 11-46.
Kenawy M.A., M. El Fihi, S. El Konsol, M.A. Fedel, and A.M. Basha (1976). Procetn
Inter. Conf. Neuherberg Munchen 2, 943.
edings of the 9
th
Marchetti M., L. Tommasino, and E . Casnati (1972). Proceedings of the 8
Inter.
Conf. on Nucl. Phot, and S.S.T.D., 2, 178.
Moliton J.P., J.C. Vareille, and J.L. Teyssier (1974). Rev. Physique Appliquee, 9,
731.
th
Nicolae M. (1972). Proceedings of the 8
Inter. Conf. on Nucl. Phot, and S.S.T.D.,
2_, 178.
Somogyi G., M. Varnagyi, and G. Peto (1968). Nucl. Instr. and Methods, 59, 299.
Somogyi G., M. Varnagyi, and L. Medveczky (1969). Compte-Rendu Jourentra, ClermontFerrand, 111-86.
Somogyi G. (1972). Proceedings of the 8 t h Inter. Conf. on N u c l . Phot, and S.S.D.T.,
2, 235.
Somogyi G. (1972). Proceedings of the 8 t h Inter. Conf. on N u c l . Phot, and S.S.D.T.,
_2, 253.
Vareille J . C , and J.L. Teyssier (1972). Radioprotection, 7, 215.
Vareille J.C. (1972). These de speciality. Limoges.
Vareille J . C , A. Barussaud, J.P. Moliton, and J.L. Teyssier (1975). N u c l . Instr.
and Methods 126, 61-68.
Varnagyi M., J. Csikai, and S. Szegedi, and S. Vagy
thods, 89, 27.
(1970). Nucl. Instr. and M e -
E.S.R. STUDIES IN ELECTRON BEAM
IRRADIATED LEXAN
M. Chipara, D. Hajegan and M . Velter-Stefanescu
Central Institute of Physics, Magurele, Bucharest, P. O. Box 5206, Romania
ABSTRACT
E l e c t r o n beam i r r a d i a t e d Lexan has "been i n v e s t i g a t e d u s i n g t h e E . S . R
s p e c t r o m e t r y . The dependence of a c t i v e c e n t e r c o n c e n t r a t i o n on i r r a d i a t i o n t i m e as w e l l as t h e v a r i a t i o n o f a c t i v e c e n t e r c o n c e n t r a t i o n
on s t o r i n g t i m e and t e m p e r a t u r e have "been s t u d i e d . A c o r r e l a t i o n b e t
ween t h e e . s . r . r e s u l t s and t h e f e a t u r e s o f Lexan as s . s . n . t . d .
has
been d e v e l o p p e d .
KEYWORDS
Lexan;
latent
e.s.r.jchain
track.
scission;
active
center;
electron
irradiation;
INTRODUCTION
In l a s t y e a r s s o l i d s t a t e n u c l e a r t r a c k d e t e c t o r s ( s . s . n . t . d . ) have
been w i d e l y u t i l i s e d i n t h e s t u d y and t h e d o s i m e t r y o f i o n i z a t i n g
r a d i a t i o n , e s p e c i a l l y i n t h e i n v e s t i g a t i o n s of c o s m i c r a y s and heavy
n u c l e i . Owing t o t h e c o m p l e x i t y o f m a c r o m o l e c u l a r s y s t e m s and t o t h e
t h e o r e t i c a l and e x p e r i m e n t a l d i f f i c u l t i e s , t h e p h y s i c a l and c h e m i c a l
processes
which t a k e p l a c e i n p o l y m e r i c a l s . s . n . t . d . are incomple t e l y known ( Benton 1 9 7 0 ) . Some a u t h o r s t r i e d t o d e s c r i b e t h e i n t e r a c t i o n of t h e i o n i z a t i n g r a d i a t i o n w i t h t h e d e t e c t o r s ( F l e i s h e r and
c o - w o r k e r s 196k; Benton 1 9 7 0 ; Katz and K o b e t i c h 1 9 6 8 ) p r o v i d i n g a way
t o e v a l u a t e t h e energy d e p o s i t e d by t h e i n c i d e n t p a r t i c l e t h r o u g h
s.s.n.t.d.
However, t h e y have n e g l e c t any f e a t u r e s o f s . s . n . t . d . as
p o l y m e r . The e f f e c t s o f p r i m a r y e x c i t a t i o n s , t h e p h y s i c a l and chemic a l s t r u c t u r e of t r a c k s , the response of polymeric d e t e c t o r s t o
v a r i o u s r a d i a t i o n ( gamma, e l e c t r o n s , heavy n u c l e i , cosmic r a y s , . . . )
are not w e l l e s t a b l i s h e d ( Benton 1 9 7 0 ) . The energy o f i n c i d e n t r a d i a t i o n may be a b s o r b e d t h r o u g h t h r e e modes ( Benton 1 9 7 0 ) : e l e c t r o n i c d i s p l a c e m e n t s , atomic d i s p l a c e m e n t s and n u c l e a r r e a c t i o n s . As
t h e v e l o c i t y o f i o n i z a t i n g p a r t i c l e s i s not very l o w , o n l y t h e e l e c t r o n i c d i s p l a c e m e n t s have been c o n s i d e r e d as a p r i m a r y mode o f i n t e r -
S.S.N.T.D. D*
75
M. Chipara, D . Hasegan and M. Velter-Stefanescu
76
a c t i o n between r a d i a t i o n and p o l y m e r . E . S . R . a l l o w e d us t o measure
t h e number of u n p a i r e d e l e c t r o n s g e n e r a t e d by t h e i n c i d e n t r a d i a t i o n
(owing t o chain s c i s s i o n ) . The m a c r o m o l e c u l a r chain f r a c t u r e s
induce a d i s t r i b u t i o n of m a c r o m o l e c u l a r masses around t h e
incident
particle trajectory;
t h e s e masses are l o w e r than t h e i n i t i a l masses
of m a c r o m o l e c u l a r c h a i n s and determine t h e l a t e n t t r a c k s h a p e .
As
t h e e t c h i n g r a t e depends on chain m o l e c u l a r masses ( t h e s o l u b i l i t y
p a r a m e t e r i n c r e a s e s w i t h i r r a d i a t i o n ) , t h e e t c h e d t r a c k shape
is
i n d u c e d by t h e shape o f l a t e n t t r a c k .
EXPERIMENTAL RESULTS
Commercially a v a i l a b l e p o l y c a r b o n a t e , known as Lexan has been i r r a d i a t e d w i t h e l e c t r o n s a c c e l e r a t e d in a l i n e a r a c c e l e2 r a t o r up t o
3
MeV. E l e c t r o n beam i n t e n s i t y has been about 2 5 u A / c m . I r r a d i a t i o n has
been c a r r i e d out at room t e m p e r a t u r e . The samples have been s t u d i e d
by p a r a m a g n e t i c r e s o n a n c e , w i t h a JES-ME-3X s p e c t r o m e t e r in X and Q
b a n d s . In t h e t i m e i n t e r v a l between t h e i n s t a n t at which t h e i r r a d i a t i o n s t o p s and t h e i n s t a n t at which measurements have been c a r r i e d
o u t , t h e samples have been s t o r e d in l i q u i d n i t r o g e n , i n o r d e r
to
p r e v e n t a c t i v e c e n t e r r e c o m b i n a t i o n . In b o t h X and Q b a n d , t h e r e s o nance spectrum ( F i g . l a , b ) i s an a s y m e t r i c a l
l i n e with the gyromagnetic f a c t o r g = 2 . 0 0 5 3 ( c l o s e d t o t h e g y r o m a g n e t i c f a c t o r
of
f r e e e l e c t r o n , g = 2 . 0 0 3 6 ) , c o n s i s t i n g o f a s u p e r p o s i t i o n of
two
predominant l i n e s with very s l i g h t l y d i f f e r e n t
g
factors.
Fig.
1.
E.S.R.
spectrum o f
i r r a d i a t e d Lexan
77
E.S.R. Studies
Dependence of a c t i v e c e n t e r c o n c e n t r a t i o n on i n t e g r a l d o s e , f o r t h e
same c o n s t a n t dose r a t e , has been s t u d i e d ( F i g . 2 ) . A maximum
of
t h e a c t i v e c e n t e r c o n c e n t r a t i o n has been n o t i c e d f o r an i r r a d i a t i o n
time o f about 1 2 0 s e c o n d s .
I r r a d i a t i o n at h i g h e r doses r e v e a l e d
a
d e c r e a s e of a c t i v e c e n t e r c o n c e n t r a t i o n , owing t o t h e i n c r e a s e
of
the recombination processes weight.
CO
o
100
i
80
60
40
20
100
Fig.
2.
200
300
400
600
500
t; (sec)
Dependence o f a c t i v e c e n t e r c o n c e n t r a t i o n
on i r r a d i a t i o n t i m e
In o r d e r t o s t u d y t h e k y n e t i c o f t h e r e c o m b i n a t i o n p r o c e s s e s , t h e
dependence o f a c t i v e c e n t e r c o n c e n t r a t i o n on s t o r i n g t i m e and t e m p e r a t u r e has been s t u d i e d ( F i g . 3 ) .
CD
o
70
*
*
}
50
=4
* i
10
i
5
190
230
270
310
350
i
390
430
T(°K)
Fig.
3.
Active
center concentration
on t e m p e r a t u r e
dependence
78
Measurements s t a r t e d from t h e l i q u i d n i t r o g e n t e m p e r a t u r e ,
t e m p e r a t u r e s , w i t h a 2 0 d e g r e e s p e r 7 minutes t e m p e r a t u r e
in t i m e . Experimental errors f o r temperatures l y i e s within
degrees.
t o higher
gradient
+ 0.5
~"
INTERPRETATION OF EXPERIMENTAL RESULTS
The r e s o n a n c e l i n e has been a t t r i b u t e d ( Hama and S h i n o h a r a 1 9 7 0 ;
G r o s e s c u 1 9 7 0 ; D r a g h i c e s c u and G r o s e s c u 1 9 7 2 ; V e l t e r - S t e f a n e s c u and
Grosescu 1 9 7 8 ) t o macromolecular chain s c i s s i o n s , according t o t h e
following reactions ;
2- < >-0- + CO
( i )
: >- r -co
=
o
=
:
1
2
T h i s mechanism i s s u p p o r t e d
by t h e p r o d u c t i o n o f r e l a t i v e l y l a r g e
amounts o f CO and CO2 ( G r o s e s c u , C o n s t a n t i n e s c u , B a l l a 1 9 6 8 ; Hama
and S h i n o h a r a 1 9 7 0 ) . Around 9 0 C t h e d i s a p p e a r e n c e o f R2« c e n t e r s
has been o b s e r v e d . Around 1 9 0 C t h e a c t i v e c e n t e r c o n c e n t r a t i o n d e c r e a s e s r a p i d l y below t h e s e n s i b i l i t y o f s p e c t r o m e t e r . The same r e s u l t s have been r e p o r t e d by G r o s e s c u , C o n s t a n t i n e s c u and B a l l a ( 1 9 6 8 )
Hama and S h i n o h a r a ( 1 9 7 0 ) . As t h e a c t i v e c e n t e r c o n c e n t r a t i o n d i d
not show a s t r o n g d e c r e a s e around 9 0 C, i t i s p o s s i b l e f o r
R2. t o
r e a c t w i t h t h e oxygen d i f f u s e d in samples and t o change i n a n o t h e r
a c t i v e c e n t e r o f R2OO. t y p e . T h i s h y p o t h e s i s t a k e s i n t o account t h e
c e n t e r s a g a i n s t oxygen ( G r o s e s c u , Const a n t i n e s c u
r e a c t i v i t y of R 2
and B a l l a 1 9 6 8 ; Hama and S h i n o h a r a 1 9 7 0 ; D r a g h i c e s c u and G r o s e s c u
1972).
Measurements o f g e n e r a t i o n and r e c o m b i n a t i o n p r o c e s s e s
have
p e r m i t t e d us t o e v a l u a t e t h e a c t i v e c e n t e r mean l i f e t i m e as w e l l as
t h e a c t i v a t i o n energy ( C h i p a r a , V e l t e r - S t e f a n e s c u and Hasegan t o be p u b l i s h e d ) . In o r d e r t o e v a l u a t e t h e a c t i v e c e n t e r mean l i f e
t i m e A , t h e f r e e z i n g o f t h e r e c o m b i n a t i o n p r o c e s s e s at 0 ° K has been
c o n s i d e r e d . The t e m p e r a t u r e T^ at which t h e r e c o m b i n a t i o n p r o c e s s e s
are i n s t a t a n e o u s has been d e t e r m i n e d . C o n s e q u e n t l y , t h i s t e m p e r a t u r e
d e f i n e sKT t h e a c t i v a t i o n e n e r g y f o r chain f r a c t u r e s , a c c o r d i n g l y t o ;
E
=
a
B 1 » where
Kg i s t h e Boltzmann c o n s t a n t . T i = kk2
K has been
o b t a i n e d . For t h e a c t i v e c e n t e r mean l i f e t i m e , at room t e m p e r a t u r e ,
t h e f o l l o w i n g v a l u e has been o b t a i n e d :
A(
300 K ) = U-.U25
minutes
POSSIBLE CORRELATIONS WITH
S.S.N.T.D.
In o r d e r t o c o r r e l a t e e . s . r . e x p e r i m e n t a l r e s u l t s t o t h e f e a t u r e s of
Lexan as s . s . n . t . d . , a s i m p l i f i e d model i s s u g g e s t e d . W i t h i n t h i s mod e l o n l y t h e e f f e c t s o f t h e primary i o n i z a t i n g r a d i a t i o n i s c o n s i d e r e d . As t h e a c t i v e c e n t e r g e n e r a t i o n i s c o r r e l a t e d t o t h e energy de p o s i t e d by t h e i n c i d e n t p a r t i c l e i n d e t e c t o r , t h e d i s t r i b u t i o n o f
t h e d e p o s i t e d energy around t h e i n c i d e n t p a r t i c l e t r a j e c t o r y
in t h e
n o n r e l a t i v i s t i c c a s e , has been c o n s i d e r e d .
2
E(
y )
2
2
2
z2e MTre v y i
0
-b
< y < b
-b
> y > b
(
2
)
E.S.R. Studies
79
where
v
i s the p a r t i c l e v e l o c i t y ,
m t h e mass of t h e i n c i d e n t p a r t i c l e , Z t h e charge o f t h e i o n i z a t i n g p a r t i c l e ,
e Q the d i e l e c t r i c
c o n s t a n t of medium, e
the electron charge,
y t h e d i s t a n c e from t h e
p o i n t at which t h e e n e r g y E ( y ) i s d e p o s i t e d t o t h e p a r t i c l e t r a j e c t o r y and b
i s t h e impact p a r a m e t e r . A d m i t t i n g t h a t t h e i o n i z a t i o n
t a k e s p l a c e i f t h e energy d e p o s i t e d i n t h e p o i n t
y
i s g r e a t e r than
t h e i o n i z a t i n g p o t e n t i a l I and t h a t t h e number o f a c t i v e c e n t e r s i s
p r o p o r t i o n a l t o E ( y ) / I , t h e a c t i v e c e n t e r d i s t r i b u t i o n around
the
particle trajectory is
2aE(y)/I
-b < y < b
N( y )
-b
> y > b
( 3 )
where
a i s an a d j u s t a b l e c o n s t a n t . In t h e d e r i v a t i o n o f e q . 3 ,
E ( + b ) = I has been s u p p o s e d . The c o n c e n t r a t i o n o f a c t i v e c e n t e r s i s ,
d(x)
N = kitj
J
N(y)ydydx
( h )
where
d i s t h e t r a c k d i a m e t e r and L i s t h e d e t e c t o r t h i c k n e s s
( L<particle residual
range ) . A c o n s t a n t v e l o c i t y o f t h e i n c i d e n t
p a r t i c l e as w e l l as b £ d have been s u p p o s e d . As we have a s s o c i a t e
t o each p a i r of a c t i v e c e n t e r a s c i s s i o n o f t h e m a c r o m o l e c u l a r c h a i n ,
i t i s p o s s i b l e t o c o r r e l a t e t h e changes i n t h e d i s t r i b u t i o n of macrom o l e c u l a r masses on i r r a d i a t i o n t o t h e d i s t r i b u t i o n o f a c t i v e c e n t e r .
I f t h e i n i t i a l polymer c o n s i s t s of c h a i n w i t h t h e a v e r a g e m o l e c u l a r
mass
M Q , and t h e i r r a d i a t e d polymer c o n s i s t s of c h a i n w i t h t h e
average m o l e c u l a r mass M, t h e f o l l o w i n g c o r r e s p o n d e n c e between M Q, M
and N may be d e r i v e d .
M 0 = BMN
( 5 )
where
B i s a c o n s t a n t and N i s t h e a c t i v e c e n t e r c o n c e n t r a t i o n . As
N depends on i n t e g r a l dose ( which i s p r o p o r t i o n a l t o t h e i r r a d i a t i o n t i m e f o r a c o n s t a n t dose r a t e ) , r e s u l t s :
M"
1
= B N Q/ M 0 + B x t f ( t )
( 6 )
where
B^ i s a c o n s t a n t , t
i s the i r r a d i a t i o n t i m e , f ( t ) d e s c r i b e s
t h e g e n e r a t i o n p r o c e s s e s and N 0 i s t h e a c t i v e c e n t e r c o n c e n t r a t i o n
of t h e u n i r r a d i a t e d p o l y m e r . As t h e e t c h i n g r a t e depends on l / M , t h e
equation ( 6 ) turns t o :
v = vQ + Kjtf(t)
( 7 )
where
v
and v Q r e p r e s e n t s t h e e t c h i n g r a t e f o r t h e i r r a d i a t e d and
t h e u n i r r a d i a t e d p o l y m e r , r e s p e c t i v e l y . The change o f B^ i n
takes
i n t o account t h e s o l v e n t n a t u r e , i t s c o n c e n t r a t i o n and t h e
etching
t e m p e r a t u r e . The e x p r e s s i o n ( 7 ) i s i n agreement w i t h t h e e x p e r i mental r e s u l t s o f Frank and Benton ( 1 9 7 0 ) , as
f ( t ) depends l i n e a r l y on t i m e and t h e r e f o r e
v
depends q u a d r a t i c a l l y on i r r a d i a t i o n
t i m e . T h i s p i c t u r e i s s u p p o r t e d by t h e e . s . r . e x p e r i m e n t a l r e s u l t s ;
t h e a c t i v e c e n t e r dependence on t e m p e r a t u r e has r e v e a l e d t h e d i s a p p e a r e n c e o f a c t i v e c e n t e r around 1 9 0 C. Many a u t h o r s ( F l e i s h e r and
P r i c e 1 9 6 3 ;Khan and Durrani 1 9 7 2 ;Somogyi 1 9 7 2 ) have r e p o r t e d
t r a c k s d i s a p p e a r e n c e between 1 8 0 ; 2 0 0 C.
80
CONCLUSIONS
The u t i l i t y o f e . s . r . s p e c t r o m e t r y in t h e s t u d y of p h y s i c a l
and c h e m i c a l p r o c e s s e s which t a k e p l a c e in s . s . n . t . d . has been r e v e a l e d . The n a t u r e , c o n c e n t r a t i o n and dependence o f a c t i v e c e n t e r
c o n c e n t r a t i o n on s t o r i n g t i m e and t e m p e r a t u r e as w e l l as t h e dependence of a c t i v e c e n t e r s on i n t e g r a l d o s e , have been i n v e s t i g a t e d , T h e
a c t i v e c e n t e r mean l i f e time as w e l l as t h e a c t i v a t i o n energy
for
m a c r o m o l e c u l a r c h a i n s c i s s i o n s have been e v a l u a t e d . A p o s s i b l e c o r r e l a t i o n among t h e d e p o s i t e d energy d i s t r i b u t i o n , t h e a c t i v e c e n t e r
c o n c e n t r a t i o n , t h e a v e r a g e m a c r o m o l e c u l a r masses and t h e e t c h i n g
r a t e has been d i s c u s s e d .
REFERENCES
Benton, E . V . ( 1 9 6 8 ) . A s t u d y o f c h a r g e d p a r t i c l e t r a c k i n c e l l u l o s e
n i t r a t e . NRDL - TR - 6 8 - Ik.
B e n t o n , E . V . ( l 9 T o ) . On l a t e n t t r a c k f o r m a t i o n i n o r g a n i c n u c l e a r
charged p a r t i c l e t r a c k d e t e c t o r s . R a d . E f f e c t s , 2 , 2 7 3 - 2 8 0
C h i p a r a , M . , V e l t e r - S t e f a n e s c u , M . M . , and Hasegan, D . To be
p u b l i shed.
D r a g h i c e s c u , P. and G r o s e s c u , R . N u c l e a r magnetic r e l a x tah t i o n i n some
Congress
i r r a d i a t e d p o l y m e r s . In V. Hovi ( E d . ) , P r o c . X X V I I
AMPERE, F i n l a n d 1 9 7 2 , p . 2 2 2 .
F l e i s h e r , R . L , and P r i c e , P. B. ( 1 9 6 3 ) . Tracks o f c h a r g e d p a r t i c l e s
i n high p o l y m e r s . S c i e n c e , lUo , 1 2 2 1 .
F l e i s h e r , R . L . , P r i c e s , P . B . , W a l k e r , R.M. and Hubbaed, E . L . ( I 9 6 U )
Track r e g i s t r a t i o n i n v a r i o u s s o l i d s t a t e n u c l e a r d e t e c t o r s ,
Phys. Rev. 1 3 3 A, 1 U U 3 .
Frank, A . L . and E . V . B e n t o n ( l 9 7 o ) . D i e l e c t r i c p l a s t i c s as high e x p o s u r e gamma ray d e t e c t o r s . Rad. E f f e c t s 2 , 2 6 9 .
G r o s e s c u , R . , 0 . C o n s t a n t i n e s c u and D . B a l l a ( 1 9 6 8 ) , E . S . R . o f i r r a d i a t e d p o l y c a r b o n a t e s , R e v . R oum. P h y s . ih , 1 2 7 1 .
G r o s e s c u , R . ( l 9 7 o ) . P r o t o n - s p i n - l a t t i c e r e l a x a t i o n in i r r a d i a t i o n p o l y c a r b o n a t e s . In I . U r s u ( E d . ) P r o c . XXVI C o n g r e s s AMPERE
B u c h a r e s t , Romania, p . 5 6 l .
Hama, Y . , and K. S h i n o h a r a , E . S . R . s t u d i e s o f p o l y c a r b o n a t e s i r r a d i a t e d by y r a y s and u l t r a v i o l e t l i g h t . J . Polym. S c i . j5, 6 5 1 .
K a t z , R . , and E . J . K o b e t i c h ( 1 9 6 8 ) . Formation o f e t c h a b l e t r a c k s i n
d i e l e c t r i c s . Phys .Rev . ,
. 1 7 0 , hoi.
Khan, H . A . and S . A . D u r r a n i ( 1 9 7 2 ) . E f f i c i e n c y c a l i b r a t i o n o f s o l i d
s t a t e nuclear t r a c k d e t e c t o r s . Nucl. I n s t r . Methods, 9 8 , 5 8 3 .
Somogyi, G. ( 1 9 7 2 ) . I N f l u e n c e of t h e r m a l e f f e c t s on t h e t r a c k r e g i s t r a t i o n c h a r a c t e r i s t i c o f p l a s t i c . Rad. E f f e c t s , l 6 , 3 6 9
V e l t e r - S t e f a n e s c u , M . , and R . G r o s e s c u , The e l e c t r o n s p i n l a t t i c e
r e l a x a t i o n at low t e m p e r a t u r e i n i r r a d i a t e d p o l y c a r b o n a t e , R e v .
Roum. P h y s . , 2 3 , 3 6 9 .
ATOMIC DISPLACEMENT EFFECTS
FROM HEAVY ION INDUCED
COULOMB EXPLOSION
K. O. Groeneveld, E. Schopper and S. Schumann
Institut fur Kernphysik der J. W. Goethe-Universitdt,
Frankfurt/M, Federal Republic of Germany
ABSTRACT
Recent experiments of heavy ion induced Coulomb explosion of gaseous molecular targets give evidence a) of the high energies of the exploding fragments and b) of the
high cross section of this process. Arguments are discussed that this process can
play an important role in both nuclear track formation in solids and in radiation
damage in biological samples.
KEYWORDS
Track formation in solids; heavy ion physics; Coulomb explosion; wake-potential; radiation damage.
INTRODUCTION
A number of concepts has been discussed as possible production mechanisms for latent image of nuclear tracks in solids (see e.g. Fleischer, Price and Walker, 1975,
and Katz and Kobetich, 1 9 6 8 ) . A recent survey on the various track formation concepts, their merits and shortcomings is given by Paretzke (1979) .
Fleischer, Price and Walker (1975) note that "we find ourselves in the apparently
paradoxial situation where we know that the damage along tracks in inorganic solids
consists mainly of displaced atoms; yet the damage results from interactions with
the electrons in the detector, not from direct atomic scattering". In the present
paper we discuss atomic displacement effects from heavy ion induced Coulomb e x plosion. In the following chapters we will discuss first experimental evidence of
heavy ion induced Coulomb explosion of molecular targets. Next we deal with the energetics of Coulomb explosion and mean energy loss; and finally w e consider the ionization probability followed by Coulomb explosion.
EXPERIMENTAL EVIDENCE OF COULOMB
Kinematic Experiments of Molecular Projectile
+
EXPLOSION
Ions
Molecular ions (e.g.HeH ) of many different species are copiously produced in ion
sources and can b e accelerated to, say, MeV energies. Molecular ions interacting at
MeV energies with atoms under single collision conditions may loose their binding
electron(s); the, then, positively charged fragment ions are repelled b y their m u -
81
82
K.
t u a l
ges
Coulomb
q i
1
t h e
f o r c e .
q 2
p r e s e n t s
G r o e n e v e l d ,
D i a t o m i c
are
s e p a r a t e d
the
a n g u l a r
p r o j e c t i l e
frame
m o l e c u l a r
v e r y
and
o f
E.
Schopper
ions
v i o l e n t l y
energy
and
( e . g .
i n
H£)
t h e
(Kanter
and
Schumann
w i t h
bond
l e n g t h
r
Coulomb
f i e l d U = q i
+
o f
H
from e x p l o d i n g
d i s t r i b u t i o n
r e f e r e n c e
S.
and
e / r Q.
c h a r F i g u -
m o l e c u l e s
Ht
1979).
c o l l e a g u e s ,
COUNTS
re
i n
and
O.
PROTON
F i g .
ENERGY (keV)
(a)
1
J o i n t
s i n g
a t
e n e r g y - a n g l e
from
m
7.8
t h e
T o r r
spectrum
o f
beam
l a r
gy
h a l f
t e r
way
o f
+
o f H2
(1.2
p r e s s u r e ,
those
i n
w i t h
ANGLE
d i s s o c i a t i o n
g e t
t a r g e t
PROTON
(b)
p r o t o n s
d i r e c t i o n ,
an
o f
(c)
between
o f
t h e
and colleagues
The
1.2
two
a r i -
MeV)
Ar
from
t h e
peaks
amount
m e t e r " ,
o f
measured
r i n g
i s
i n d e p e n d e n t
i s
i s o t r o p i c
w i t h
E l e c t r o n i c
o f
under
many
i o n i z a t i o n
e l e c t r o n s .
energy
t o
r e a c h
a n a l y s e r .
o b s e r v a t i o n
o f
s i n g l e
o f
o f
atoms
and
F i g u r e
a n g l e s
e l e c t r o n s
i s
t h e
d i r e c t i o n
o f
t h e
i o n
i s
c o n d i t i o n s .
s p e c i e s
E x p l o d i n g
under
emerging
from
an
i . e .
i n
( b ) .
When
r e s p e c t
e m i t t e d
i o n
From
t o
ro '
/ e
q2
i m p o r t a n t
K a n -
S i m i l a r
e . g .
i - e-
to
e x p l o s i o n :
K a n t e r
impact
e
note
The
and
t " r inn g
t h a t
have
d i a -
t h e
Coulomb
e x p e r i m e n t s
a
s u r f a c e
e l e c t r o n
t h e
n e c e s s a r i l y
i o n i z a t i o n
i n s i d e
s o l i d
such
i n
(see
c a l l e d
c r e a t e d
t h e
the
e n e r -
h e i g h t
e x p l o s i o n
been
p e r -
1979).
c o l l e a g u e s ,
M o l e c u l e s
heavy
a r e
p r e s e n t s
w i t h
q^
i t
p e n e t r a t e
2
=
a c c u r a c y ;
e l e c t r o n s
e v e n t s .
E ^
h i g h
o f
t a r -
a n g u -
(1979).
energy
c o l l i s i o n
d i f f e r e n t
These
c o l l i s i o n
j o r i t y
w i t h
D e e x c i t a t i o n
s i n g l e
gy
e x p l o s i o n
be
t h e
Each
Coulomb
can
o f
formed
t h e
energy
gas
MeV
2
The
i n
c o r r e s p o n d i n g
p r o t o n s
1/2
p r o t o n s
c o r r e s p o n d i n g
emerging
those
energy
The
(mrad)
emergent
f o r w a r d
s o l i d
and
energy
some
t o
pass
i o n
and
a l s o
when
i n t o
t a k e n
beam
w i t h
the
an
have
low
from
s u f f i c i e n t
e l e c t r o n
under
e n e r -
d i f f e r e n t
d i r e c t i o n .
v e r y
e j e c t i o n
observed
e l e c t r o n s
s p e c t r a
heavy
d i r e c t i o n
means
e l e c t r o n s
The
e n e r g i e s
ma-
D i s p l a c e m e n t
83
E f f e c t s
YIELD OF SECONDARY ELECTRONS —
Atomic
F i g .
Energy
2
s p e c t r a
o b s e r v a t i o n
c o l l i s i o n
(Folkmann
i n s i d e
t r a c k
f o r m a t i o n
der
e t
s i o n .
Auger
b r o a d e n i n g
t a t i v e l y .
r a t i o n s
and
N)
g i v e s
t a r g e t s
c o l l e a g u e s
i m p i n g i n g
t h a t
1979)
i n f o r m a t i o n
a t
d i f f e r e n t
M e V ) ->
(183
C - f o i l
Folkmann
a n d C o l l e a g u e s
E l e c t r o n s
measured
h e r e
e l e c t r o n s .
They
b y Katz
number
o f
a n d K o b e t i c h
w i t h
a d d i t i o n a l
t h e Coulomb
w h i c h
h a s been
b o t h
as
t a r g e t
o b s e r v e d
o n t h e charge
t h e s o l i d
t h e i r
from
s u f f e r
a l s o
a
e l e c t r o n i c
Coulomb
k i n d
o f
e x p l o D o p p l e r -
a n d c a n b e c a l c u l a t e d
s t a t e
Scha-
p r o j e c t i l e ) .
r e l a x
energy
a r e
i n t h e
(compare
p e r
atoms
e x p l o s i o n
(1976).
t h e agens
(1968),
e j e c t e d
k i n e t i c
a f t e r
o u t s i d e
a r e known
e l e c t r o n s
i n t e r a c t i o n
r e c e i v i n g
e m i t t e d
t o
i n
a f t e r
impact
t h e D o p p l e r
1976, 1 9 7 8 ) .
o f
e . g . o f
( I s 2s
a r e l o s t
T h e cross
p u b l i c a t i o n s
fragments
n p )-
i n
heavy
i o n s ,
b r o a d e n i n g
o n , s a y ^ - m o l e c u l e s
t h e m o l e c u l a r
e l e c t r o n s
f e r r e d
a f t e r
e l e c t r o n s
t h e Xe
a n d t h e e l e c t r o n i c
q u a n t i c o n f i g u -
i n v o l v e d .
p o p u l a t i o n
the
ions
a f t e r
( G r o e n e v e l d ,
e x p l o s i o n
s i z e d
o r
e l e c t r o n s
I t
M o l e c u l a r
lomb
d u r i n g
from
0
From
e l a b o r a t e d
f o r t h e t o t a l
p r o j e c t i l e
e x c i t a t i o n
a s d e l t a
concept
(1978)
a l .
M o l e c u l a r
t h e s o l i d
i o n i z a t i o n
system.
1976).
a n d c o l l e a g u e s ,
known
o f
angles
i s
o f
s e c t i o n
i n
a r e
b y Mann
fragment
f o r t h i s
t h e o r d e r
1.
i n
o f
a
a n d C o l l e a g u e s
a n d 2.
s i n g l e
g i v e
e v i d e n c e
Auger
p r o c e s s
l i n e s
w i t h
l O " ^ c m ^ . i t
e l e c t r o n i c a l l y
c o n f i g u r a t i o n s ) ,
each
s i m i l a r l y ,
t h e o b s e r v e d
h i g h l y
h i g h l y
(1976, 1978)
t h e
should
e x c i t e d
i o n i z e d
c o l l i s i o n ) .
o f
Cou-
( F i g . 3, M a n n
+
K r ^ °
(1.4 M e V /
(60
b e
t o
T h e r e a d e r
f o r f u r t h e r
empha-
(abundant
80
%
o f
i s r e -
d e t a i l s .

solid state nuclear track detectors

Transcription

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