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Proceedings of the 3 International Conference on Luminescence Dosimetry

Research Establishment Risoslash Roskilde

Publication date1971

Document VersionPublishers PDF also known as Version of record

Link back to DTU Orbit

Citation (APA)Research Establishment Risoslash R (1971) Proceedings of the 3 International Conference on LuminescenceDosimetry Denmark Forskningscenter Risoe Risoe-R No 249(pt1)

Risfi Report No 249 Plaquortl(pp l-laquo3)

I iJ | Danish Atomic Energy Commission bullSi a Research Establishment Riso

Proceedings of The Third International

Conference on Luminescence Dosimetry

held at the Danish AEC Research

Establishment Riso 11-14 October 1971

Sponsored by The Danish Atomic Energy Commission and

Hie International Atomic Energy Agency

December 1971

Salt distributor JoL Ojattofup 87 Soslashlvgade DK-1307 Copenhagen K Dumark

AraUaNt OH txtkang from Library Daakb Atomic EDtrgy COBUBIHIOH RtaS DK-4000 Rmkihto

UDC 53SS7-SXA2M

December 1971 RisS Report No 249 Part I (pp 1 -443)

Proceedings of the

Third International Conference on Luminescence Dosimetry

Held at

The Danish Atomic Energy Commission Research Establishment RisO

October 11 -14 1971

Sponsored by

The Danish Atomic Energy Commission

and

International Atomic Energy Agency

Editor

V Mejdahl

Abstract

Seventy-eight papers a r e presented from the 3rd International Conshy

ference on Luminescence Dosimetry The papers a r e arranged according

to the following topics Mechanisms of Thermoluminescence (TL) TL Inshy

strumentation Improved TL Materials Propert ies of TL Materials Thershy

mally Stimulated Exoelectron Emission Radiophotoluminescence TL in

Clinical and Personnel Dosimetry Dating and Background Radiation Monishy

toring Charged Part ic le Neutron and UVdeg Response Miscellaneous Propshy

ert ies Effects and Applications

ISBN 87 550 0120 3

ISBN 87 550 0121 1

FOREWORD

This publication presents the papers given at the third International Conference on Luminescence Dosimetry The papers reflect the extensive research and development that have been accomplished since the second International Conference on Luminescence Dosimetry held at Gatlinburg Tennessee in 1968 The great number of papers seventy-eight clearly Indicates the continuing interest in this field There were 144 registered attendees representing twenty-seven countries and three international orshyganizations Austria Belgium Brazil Bulgaria Canada Czechoslovakia Denmark Finland France Germany (DDR and the Federal Republic) Greece Hungary India Israel Italy Japan Mexico The Netherlands Norway Poland Portugal Sweden Switzerland United Kingdom U S A Yugoslavia CERN IAEA and WHO

In connection with the conference a commercial exhibition was arranged which snowed the latest developments of measuring equipment Eight comshypanies representing six countries participated in the exhibition

To enable rapid publication the papers have been reproduced directly from the manuscripts handed over by the authors A few papers were withshydrawn by the authors and in such cases only abstracts are given Discusshysion on a paper i s inserted at the end of the paper The publication i s in three parts Part I contains sessions I-V part H sessions VI-IX and part m sessions X-XU The grouping of papers into sessions appears from the l ist of contents which i s included in each volume

The assistance of Miss L Kristiansen Miss B Ramgill and the printing office staff in the publication of the proceedings i s gratefully acshyknowledged by the Arrangements Committee

V Mejdahl

CONFERENCE OFFICERS

Co-Chairmep

J F Fowler

Research Unit in Radiobiology Mount Vernon Hospital Northwood United Kingdom

A Scharmann University of Giessen Federal Republic of Germany

Programme Committee

K Becker Chairman

Oak Ridge National Laboratory U S A

FH Attlx

U S Naval Research Laboratory U S A

J R Cameron

University of Wisconsin U S A

J H Schulman Special Advisor U S Naval Research Laboratory U S A

Local Arrangements and Publications Committee

V Mejdahl Chairman Danish AEC RisB Denmark

CA Carlsson Vice-Chairman University of Linkfiping Sweden

L Boslashtter-Jensen Danish AEC RisO Denmark

E Pedersen

Danish AEC RisB Denmark

CONTENTS

PARTI

Page

MECHANISM OF THERMOLUMINESCENCE I Chairman S Watanabe University of Sao Paulo Brazil

Interpretation of Resolved Glow Curve Shapes in LiF (TLD-100)

from 100deg to 500degK EB Podgorsak PR MoranandJR Cameron 1

Analysis of Thermoluminescence Kinetics of CaFbdquo Mn Dosimeters

G Adam and J Katriel 9

Investigation of Thermoluminescent Lithium Borate Glasses using Electron Spin Resonance Douglas R Shearer IS

A Simple Thermoluminescence Model and its Application in Thermoluminescent Dosimetry R Abedin-Zadeh 41

Efficiency Variations of Thermoluminescent LiF Caused by Radiation and Thermal Treatments Per Spanne and C A

Carlsson 48

MECHANISMS OF TL II Chairman A Moreno y Moreno Inst of Physics Univ of Mexico Mexico

Continuous Model for TL Traps Shigueo Watanabe and Spero Penha Morato 58

The Influence of Hydroxide Impurities on Thermoluminescence in Lithium Fluroide L A DeWerd and T G Stoebe 78

Influence of OH Anion on the Thermolumiscence Yields of Some

Phosphors Toshiyuki Nakajima 90

Abnormal Thermoluminescence Fading Characteristics A G Wintte MJ Aitken and J Huxtable 105

Fading In Thermoluminescent Dosimetry Zdenek Spurny and Josef Novotny 132

Page

Effects of Deep Traps on Supralinearity Sensitisation and Optical Thermohuninescence in LiF TLD C M Sunta V N

Bapat and S P Kathuria 146

Supralinearity and Sensitization V K Jain and J B Sasane 156

Re-estimation of Dose in LiF G S Linsley and EW Mason 1 ST

Properties of Some Deep Traps in Lithium Fluoride- E W Mason and G S Linsley - 164

TL INSTRUMENTATION

Chairman T Higashimura Research Reactor Institute

Kyoto University Osaka Japan

Possible Elimination of the Annealing Cycle for Thermoshy

luminescent LiF G A M Webb and H P Phykitt 185

Significant Changes in TLD Readings Produced by AC Heater

Currents J E Saunders 209

Photon Counting as Applied to Thermolumiaescence Dosimetry

T Schlesinger A Avni Y FeigeandSS Friedland 226

Dosimeter and Reader by Hot Air Jet H Oonishi O Yamamoto T Yamashita and S Hasegawa 237

The Emission Spectra of Various Thermoluminescence Phosphors K Konschak R Pulzer and K HQbner 249

IMPROVED TL MATERIALS I

Chairman Z Spumy Nuclear Research Institute Prague Czechoslovakia

Some Thermoluminescent Properties of Quartz and its Potential

as an Accident Radiation Dosimeter D J McDougall 255

Thermoluminescent Enamels M Mihailovic and V Kosi 277

Thermoluminescent Phosphors based on Beryllium Oxide Y Yasuno and T Yamashita 290

A Study of Silver Iron Cobalt and Molybdenum as Lithium Borate Activators for its use in Thermoluminescent Dosimetry

A Moreno y Moreno C Archundia and L Salsberg 305

Page

IMPROVED TL MATERIALS II Chairman T Schlesinger Soreq Nuclear Research Centre

Yavno Israel

Sintered TL Dosimeters T Niewiadomski M Jasinska

and E Ryba 332

Studies of the Thermoluminescence of Lithium Fluoride Doped

With Various Activators M E A Robertson and W B Gilboy 350

A New TL LiF (NTL-50) Which is Unnecessary of Annealing

its Properties Especially for Application and the Results of Several Practical Cases Katsumi Naba 357

Thermoluminescent Response of Natural Brazilian Fluorite to 137

Cs Gamma-Rays S Watanabe and E Okuno 380 Thermoluminescence of Natural CaF~ and its Applications

C M Sunta 392

Improvement of Sensitivity and Linearity of Radiothermolu-minescent Lithium Fluoride G Portal F Berman Ph Blanchard and R Prigent 410

Further Studies on the Dosimetric Use of BeO as a Thermoshyluminescent Material G Scarpa G Benincasa and L Ceravolo 427

PART II

PROPERTIES OF TL MATERIALS Chairman C Carlsson Univ of LinkSping Linkfiping Sweden

Dose Relationship Energy Response and Rate Dependence of

LiF-100 LiF-7 and CaS04-Mn from 8 KeV to 30 MeV G Eggermont R Jacobs A Janssens O Segaert and

G Thielens 444

On the Non-Linearity and LET Effects of the Thermolushyminescence Response Toshiyuki Nakajima 461

On the Sensitivity Factor Mechanism of Some Thermolushyminescence Phosphors Toshiyuki Nakajima 466

The TSEE Response of Ceramic BeO covered with Different Absorbers During Gamma and X-Ray Irradiation E Rotondi and T Suppa 480

Low Temperature Monitoring Using Thermoluminescent Materials Robert D Jarrett J Halliday and J Tocci 490

Dependence of the Response of LiF TLD 100 Powder

Incorporated in Silicone Rubber on Grain Size P Bassi G Busuoli A Cavallini L Lembo and O Rimondi 504

Manufacture of Uniform Extremely Thin Thermoluminescence Dosimeters by a Liquid Moulding Technique Geoffrey A M

Webb and George Bodin 518 7

The Consistency of the Dosimetric Properties of LiF in Teflon

Discs over Repeated Cycles of Use T O Marshall K B Shaw and E W Mason 530

Influence of Size of CaFraquoMn Thermoluminescence Dosimeters 60 on Co Gamma-Ray Dosimetry in Extended Media

Margarete Ehrlich 550

THERMALLY STIMULATED EXOELECTRON EMISSION Chairman P Maushart Berthold-Frieseke Vertriebsgesellschaft GmbH Karlsruhe Germany

Exoelectronic Properties of AlgO-Solids G Holzapfel

and E CrysBou 561

Chemically Thermally and Radiation-Induced Changes in the

TSEE Characteristics of Ceramic BeO R B Gammage K Becker K W Crase and A Moreno y Moreno 573

Exoelectron Dosimetry with Oxide Mixtures M Euler

W Kriegseis and A Scharmann 589

Low-Z Activated Beryllium Oxide as a High Sensitive Radiation Detector in TSEE Dosimetry D F Regulla G Drexler and L Boros 601

TSEE Dosimetry Studies T Niewiadomsld 612

The Optical Stimulation of Exoelectron Emission J Kramer 622

Page

Characteristics of Selected Phosphors for Stimulated Exoelectron Emission Dosimetry P L Ziemer W C McArthur V L McManaman and G D Smith 632

Problems in the Use of Proportional Counters for TSEE Measshyurements L D Brown 654

Trapping Centers in CaF2Mn from Thermoluminescence and Thermally Stimulated Exoelectron Emission Measurements on Undoped and Mn Doped CaF Samples K J Puite and J Arends 680

RADIOPHOTOLUMINESCENCE

Chairman K Becker Oak Ridge National Lab

Oak Ridge USA

Formation Kinetics of Color Centers in RPL Glass Dosimeters

AM Chapuis M Chartier and H Francois 692

A RPL Dosimetry System with Fully Automated Data Evaluation M Dade A Hoegl and R Maushart 693

New Type of High-Sensitive and Soil-Insensitive RPL Glass Dosimetry R Yokota Y Muto Y Koshiro and H Sugawara 709

Laser Pulse Excitation of Radiation Induced Photoluminescence

in Silver-Activated Phosphate Glasses F Hillenkamp and D F Regulla 718

The Response of Radiophotoluminescent Glass to Co Y-and 10-30 MeV Electron Radiation L Westerholm and G Hettinger 727

Some Ways of Applying the Capabilities of Various Luminescence Methods in Personnel Monitoring M Toivonen 742

Radiation-Induced Optical Absorption and Photoluminescence of

LiF Powder for High-Level Dosimetry EW Claffy SG

Gorblcs and F H Attix 756

Page

TL IN CLINICAL AND PERSONNEL DOSIMETRY Chairman F H Attix U S Naval Res Lab Washington DC USA

Two Years Experience of Clinical Thermoluminescence Dosimetry at the Radiumhemmet Stockholm Bengt-Inge Ruden 781

Thermoluminescence Dosimetry for Clinical Use in Radiation Therapy D S Gooden and T J Brickner 793

TLD - Calcium-Fluoride in Neutron Dosimetry TLD -Calcium-Sulphate in Health Protection Service D K Bewley and pound Blum 815

Lithium Fluoride Dosimeters in Clinical Radiation Dose Measureshy

ments N Suntharalingam and Carl M Mansfield 816

A Personal Dosimeter System Based on Lithium Fluoride Thermoluminescent Dosimeters (TLD) A R Jones 831

Progress Towards Automatic TLD Processing for Large-Scale

Routine Monitoring at RisB Lars Boslashtter-Jensen and Poul Christensen 851

UV Induced Thermoluminescence in Natural Calcium Fluoride

Emico Okuno and Shigueo Watanabe 864

A Current Look at TLD in Personnel Monitoring F H Attix 879

PART m

DATING AND BACKGROUND RADIATION MONITORING Chairman M Aitken University of Oxford Oxford England

New Techniques of Thermoluminescent Dating of Ancient Pottery

I The Substraction Method S J Fleming and D Stoneham 880

New Techniques of Thermoluminescent Dating of Ancient Pottery

II The Predose Method S J Fleming 895

Progress in TL Dating at RisS Vagn Mejdahl 930

Some Uncertainties in Thermoluminescence Dating Mark C Han and Elizabeth K Ralph 948

Environmental and Personnel Dosimetry in Tropical Countries Klaus Becker Rosa Hong-Wei Lu and Pao-Shang Weng 960

Natural Radiation Background Dose Measurements With CaF2Dy TLD D E Jones C L Lindeken and R E McMillen 985

Impurities and Thermoluminescence in Lithium Fluoride MJ Rossiter DB Rees-Evans and S C Ellis 1002

CHARGED PARTICLE NEUTRON AND UV RESPONSE Chairman N Suntharalingam Thomas Jefferson University Hospital Philadelphia Pennsylvania USA

The Measurement of Dose from a Plane Alpha Source J R Harvey and S Towns end 1 015

Thermoluminescent Research of Protons and Alpha-Particles

with LiF (TLD - 700) B JShnert 1031

Thermal Neutron Dosimetry by Phosphor Activation

M R Mayhugb S Watanabe and R Muccillo 1040

Determination of the Sensitivity of the CaF2Mn Thermoshyluminescent Dosimeter to Neutrons M Prokic 1051

Triplet Exciton Annihilation Fluorescence Changes Induced by

Fast Neutron Radiation Damage in Anthracene D Pearson P R Moran and J R Cameron 1063

Mixed Neutron-Gamma Dosimetry S K Dua R Boulenger

L Ghoos and E Mertens 1074

Energy Response of Certain Thermoluminescent DosimeterB

and Their Application to the Dose Measurements H K Pen-durkar R Boulenger L Ghoos W Nicasi and E Mertens 1089

Tm-and Dy-Activated CaSO Phosphors for UV Dosimetry

K S V Nambi and T Higashimura 1107

Transferred Thermoluminescence in CaF~nat as - Dosimeter of Biomedically Interesting UltravioletRadiation Edwin C McCullough Gary D Fullerton and John R Cameron 1118

Page

MISCELLANEOUS PROPERTIES EFFECTS AMD APPUCATIONS Chairman H Francois C E A Paris France

Storage Stability of TL and TSEE from Six Dosimetry Phosphors AE Nash VH Ritz andFH Attix 1122

Optical Absorption and ESR Properties of Thermoluminescent Natural CaF2 after Heavy Gamma Irradiation Ks SV Nambi and T Higashimura 1155

Methodological Aspects on Measurements of Steep Dose Gradients

at Interfaces Between two Different Media by Means of Thermoshy

luminescent LiF Gudrun Aim Carlsson and Carl A Carlsson 1163

Kapis as a Thermoluminescent Dosimeter N T Bustamante

R Petel and Z M Bartolome 11 77

Experimental Modification of Thermoluminescence by Static and Explosive Deformation D J McDougall 11 93

Some Dosimetric Properties of Sintered Activated CaFlaquo

Dosimeters D Uran M Knezevic D Susnik and D Kolar 1195

Panel Discussion 1209

Author List 1217

List of Participants 1220

List of Exhibitors 1229

1 -

Interpretation of Resolved Glow Curve Shapes in

LiF(TLD-100) fron 100deg to 500degK

by

E B Podgorsak P R Horan and J R Caaeran

Laboratory of Medical Physics

Physics Department and Radiology Department

University of Wisconsin Madison Wis

Abstract

We note that each glow peak of LiF(TLD-100) in the temperature range

from 100deg to 500degK displays a shape peaking temperature dependence on

heating rate and lack of peaking temperature dependence laxm total light

output whidi are in detail as predicted by the most simple thermally

activated kinetics in the f irst order Randall-Wilkins limit We also

note however that the glow curve breadth is anomalously large at low

temperatures and anomalously small at high temperatures While physically

reasonable although improbable mechanisms might explain the larger

breadths there seem to exist no physically reasonable direct mechanisms to

explain the narrower breadths We propose an indirect explanation in which

the activation energy i s i t s e l f slightly temperature dependent We discuss

how this effect explains the observed results and speculate on other

implications

2 -

Introduction

Since cur abstract was submitted a detailed description of our experi-aents relating to correlations in glow peak behavior from 100 to S00K has been published1 We therefore wish to discuss here primarily an intershypretation of resolvable glow curve shapes and apply these results to the TLD-100 observations Figure 1 shows the ten glow peaks we have studied glow peaks (-1) and (-4) are not optically repqpulated with uv irradiation and this allows us to resolve die details of peaks (u) and (-3) These glow curve shapes each exhibit a 501 half-breadth asymmetry on the law temperature side and at a given heating rate neither the peaking tempershyature Tn nor temperature breadth A depend upon the peak TL intensity This behavior characterizes first order kinetics and consequently we discuss here only the Randall-Nilkins description although our results can also easily be applied to die Garlick-Gibson limit A particularly intershyesting feature is that all glow peaks in this temperature range ham essentially die same temperature breadth 4 = 20 2degC

Glow Curve Behavior

It is not appropriate to pursue all mathematical details here but a brief review of die first order kinetics of thermally activated mechanisms is useful The concentration of trapped charge carriers n corresponding to a single resolved glow peak obeys die relation

raquof-Kn (1)

where w is an activated rate function

laquo bull se-W (2)

and die TL intensity in the simplest case is some fraction of die release rate

I(t) = -cSjn (3)

The above equations can easily be integrated formally one can obtain from diem an implicit expression for die peak temperature

(Eky bull logCEky log is^Ty 1 (4)

When die glow curve is narrow AlaquoT i t is not difficult to show diat

(Ekyraquol (S)

and Eq 4 can be validly approximated as

(Ery - logis^Ty 1 (6)

Me shall return to die expression in Eq 6 later

For narrow glow curves one can also show that analytic expressions can validly be used to approximate die integration of Bqs (1) - (3) The result is

I(laquoT) - bdquo expl bull (6Ty (Eky -exp[(STy (Eky] (7)

- 3 -

where 4T i s the departure from Ta

laquoT = T-Tbdquo (8)

Figure 2 shows the predictions of Eq 7 compared to the experimental glow curve for peak (-3) peak (-3) i s chosen because i t i s the fractionally broadest glen peak and therefore tests our approximations most severely Me note die characteristic tSOt low temperature asymmetry and that the nuaerical result for the glow peak breadth at half-aaxiaua i s

A = ( 2 4 4 ) 0 ^ ^ ) TB (9)

One can now use Eqs (9) and (6) together with die experimentally observed TB and amp to determine E and s There are of course other methods as well but they give similar results and Eqs (9) and (6) most directly illustrate die effects we wish to point out

If we examine glow peak (-1) which has TB 267degK at our heating rate of 35degKmin we find

E(-l) = 76 eV (10a) s ( - l ) = S x 1012 sec1 (10b)

This value for s is to be expected i f die trapped carrier interacts as strongly with neighboring ions in die solid as die ions do with one another die s is die limiting attempt frequency and must be approximately equal to the typical DeBye lattice vibration frequencies These frequencies are indeed about 5 x 1012 s ec 1 for LiF If on the other hand we examine glow peak (-3) we find

E(-3) - 028 eV (11a) s(-3) 107 sec1 (lib)

12 -1 Expressed another way i f we assumed s(-3) = 10 sec tiwn die breadth of peak (-3) is about a factor of two broader than predicted Many explanations have been put forward to explain such anomalously large breadth of glow peaks For example fliere might exist a spread in actishyvation energies E or die trapped carrier might somehow be effectively insulated from die lattice vibrations or there might be overwhelming retrapping effects to effectively reduce die net attempt rate

Finally let i s examine glow peak (5) which has been extensively studied because of i t s use as die primary dosimetry glow peak Here we find not an anomalously large breaddi but an anomalously narrow breadth While i t i s not difficult to give plausible mechanisms to broaden a l ine i t i s very difficult to propose narrowing mechanisms The parameters determined are

E(S) - 22 eV (12a) s(5) laquo 1023 sec1 (12b)

Similar results are also obtained by measuring die logarithmic change of Ta as 3tT i s varied widi an analysis according to Eq 4

The point we wish to emphasize i s that while reasonable although

- 4 -

peihaps unlikely explanations can be Bade for s raquo 10 in glow peak (-3) there exists no simple physically reasonable mechanism for an actual s - 1 0 in peak (S) because this i s a factor of at least 10l larger than the limiting lattice interaction frequencies in the solid

He have found that we can resolve these difficulties siaply by assuming that die activation energy E i s very slightly temperature dependent ke will not present die detailed mathematics here but the following results are obtained

1 Mien an observed glow peak i s narrow 6laquoT_ then a simple analytic approximation i s always valid in integrating the kinetic equations Eos ( l ) - (3) this includes the possibility of a temperature dependent activation energy The most important relation i s

w(T)dt = wp T)1 [ariogw]1 C13) o

2 The resulting glow curve descriptions have exactly the same form as Eqs (4) through (9) except that E and s are replaced by the parameters E and s where

E - ftSOslashECBUlftg (B - 1kT) (14a)

s - expCtE-ECyikys (14b)

3 In Eq 6 the difference between E and E(T) i s exactly balanced by the difference between s and s 4Thus Eg 6 remains valid independent of whether one uses E and s or E and s

4 For glow peak (5) a slight increase in E with temperature amounting to a fractional effect of less than 10~3 (K1) easily accounts for the anomalously narrow breadth and gives a n s = 1 0 resulting from an actual interaction rate of s - 1012

5 Ml other aspects of shape breadth peak height behavior etc are preserved according to the basic Randall-Wilkins results

As a final speculation we propose that other slight temperature deshypendences account for a l l anomalous breadths For example one need not invoke the somewhat unlikely existence of dominating raquotrapping terms to explain the large breadth of peak (-3) since only a small temperature dependence of E provides the same resulting behavior

He can also speculate further on die E vs E behavior l e t us suppose as a very crude model that a l l glow peak traps are roughly the same character for example basically a weak coulomb-like binding stabilized by the surroinding ions As die temperature increases from 0K die lattice undergoes tfiermal expansion He might expect diat die trap depth wi l l f irst increase due to die reduction of die neighboring ion repulsive potentials and with continuing temperature increase die binding wil l eventually begin to decrease due to reduction of the Coulomb attraction Thus die fractional temperature dependence of E for each glow peak would show leading term of the form

- 5 -

E - E A ( l a T - BT2) CIS)

which can be rewritten

E bull Eo(l - b f f - y 2 ) (16)

We think i t i s interesting that by choosing b bull 10 (K) and T - 300K we can f i t a l l the observed clow curve shapes while retaining a single activation frequency s - 1012 sec1 characteristic of lattice vibration interactions and negligible retrapping

References

(1) E B Podgorsak P R Hsran and J R Csjeron JAP 42 2761 (1971)

(2) P R Koran E B Podgorsak USAEC Report COO-1105-164 August 1971

IMs wort wis supported by the United States tonic Energy Agency and by the (ltS nir Force Office of Scientific Research

- 6 -

I I I i i mdash I mdash I 1 1 r i

Eacute 8 8 8 8 8 5 8 8 2 ni) aiuwraquo iron

Tmdashimdashimdashimdashimdashimdashr

SO -40 -30 -20 -10 0 ST-(T-Tmax) [degk]

Figure 2 Glow peak (-3) of LiF(TLD-100) The dotted curve is calculated from Eq 7 and the undotted line is the experimentally measured glow curve

Fowler

Tour explanation of a too narrow peak in terms of a dependence of activation

energy on temperature is Interesting How did you come to this conclusion

What physical processes could lead to such a dependence and are the orders

of magnit ie involved reasonable

Moran

First we looked for a single explanation which could give low-temperature peaks a too large breadth and high temperature peaks a too small breadth At least for low Irradiation levels in l iF (TLD-Ioo) a reasonable single explanation wlaquolaquo~ E = E(T) A possible physical process i s suggested in the written version of thiB paper we suggest that thermal latt ice expansion can give a fractional variation of the form

B(T) = E (1 - b(0Wr )2gt o o By choosing bo-lO-7 C^)2 and If- 2$0degti we can f i t the 0^ and o of a l l LiF (TLD-IOO) strong resolvable glow peaks using only a strong-coupling

12 -1 lattice vibration interaction frequency s = 5x10 sec bull

Analysis of Thermoluminescence Kinetics of CaFMn Dosimeters

n Adam and

T Katriel

Nuclear Research Centre - Negev PnB 9001 Beer - Sheva Israel

Abstract

A new approach to the analysis of glow curves is used to study the

kinetics of the tnermoluminescence of Cal iMn dosimeters Activation

energies frequency factors and related parameters are obtained The

measurements were carried out on the MRLE themoluminescence dosimeters

using a PNH 80] reader in the temperature ranfes 300 - 700 degK The

computational aspects of the analysis are discussed and the computer

program performing the entire analysis using as an input the glow curve

data i s described in the appendix

Introduction

The analysis of thermoluminescence glow curves is a conventional

and powerful method for the determination of activation energies

frequency factors and related kinetic parameters for the processes involved

A new method of analysis has recently been suggested by Haxia e t al

who also applied i t to the thermoluminescence of ZnS and NaRr The glow

curves involved consist of single peaksTt is interesting to apply the

method to a more complicated glow curve The despread use of die

MBLE CaF2Mn dosimeters which have three peaks in their glow curves

as well as the ease with which their glow curves are obtained by use

of the commercial reader made them a suitable example for the present study

Description of the Method

The kinetic equation governing the light emission during a themc-

-luminescence transition is assumed to be

-dnjdt - sexpC-KkTHBjimiVtACN-n^Biiijl (1)

where

m Ccm) is the concentration of holes lying in the ith type luminescent

center

s(sec ) is the frequency factor

E(eV) is the thermal activation energy

A and Bj (cm sec1) are the probability factors respectively fbr

raquotrapping and recombination with the ith type center

N(cm~) electronic trap concentration

n(cm3) i s the trapped electron concentration

k is the Boltxman factor and T the absolute temprature

From this equation the following equation for the line shape of the

glow curve was developed in ref (1)

iog[irr)(cose bull sinescm(s2(T) bull asm)] bull -ECT bull y (2)

I(T) being the intensity of the emitted light at temperature T raquo Tfinal

A laquo I(T)dT and S(T) bull I(T)dT 0 and u are constants Tfinal T

related to the kinetic parameters For the correct value of 6 eq(2)

expresses a linear dependence of

y bull log[t(T)(cose bull sinBS(T)V((T) bull AS(T))] on x - 1T

The numerical analysis involved in obtaining the proper value of 9 is

described in ref (1)

bull A typographical error was noted in eq 23 of ref 1 This equation

should read B bull -keov(xy)v(x) - -kv(y)cov(xy)

- u -

After the right value of 0 has been obtained the activation energy

and the constant u are determined from the slope and the intercept

respectively of the linear curve The ratio AB and the frequency factor

are expressed in ref (1)_ in terns of these partmeters

Measurements and Results

As was noted above the investigated sample was CaF tMn in the form

of a thermoluminescent dosimeter type PNP 292 produced by MBL

The dosimeters were irradiated by an X - ray machine with a maximum

energy of 45 JteV to a dose of about 1000 R The dosimeters were then

heated using the MRLH thermoluninescence dosimeter reader type PMH 801

from room temperature to about 700 K The heating rate i s 45 per

second The glow curves were recorded during the heating period using

a special output provided in the reader The points on the glow curve

were then used as an input to the computer program described in the

appendix the intensity being measured in arbitrary units and the tenprature

in degrees centigrade The rectified data i s represented in figs 23 4

The obtained results are summerzed in the following table

peak I

peak IT

peak III

activation energy eV

120

165

169

peak temp

382

447

536

frequency factor s

S9810

tnW1

414laquo10

AB

237

599

703

The first peak has a particularly low activatio energy which is compensated

with a low frequency factor The roles of the activation energy and the

frequency factor in defining the peaks tenprature can be judged fro

1 2 -

the relation

Esexp(-EkT) - C

where C is a constant depending on som general characteristics of the peak ~

and T is the temperature at the peaks maximum This relation is derived

froa eq 11 of ref 1

Appendix Description of the Computer Program

The glow curve data is introduced as a set of valuesof the emission

intensity versus the corresponding temperatures These are represented

as a linear combination of a few Gaussians in the form N

I(T) x T Ciexpt-OitT-ti)2] = CTf (3) W

The non - linear parameters [ a^t^l are varied in order to optimize

the representation The vector of linear parameters i s obtained as M M

C - S - v where S^ bull T fiCTk)fj(Tv) and Y j - T ICT^fjOi)

The analytic representation i s compared with the experimental data

in fig 1 The analytic representation i s used in order to determine the

rectifying value of 8 hy minimising R bull O-P) p being defined in

eq 22 of ref 1 The appropriate value of 8 is used to determine the

activation energy frequency factor and related kinetic parameters

References

1) V Maxia S Oralis and A Rucci Journal of Luminescence J 378 - 388 (1971)

- 13 -

XS

lt 15

10

I point experimental point raquobulllaquo

350 400 450 500 560 600 650 femp K

Fig 1 Cnonarison of analytic versus experimental flow curve

-10

-15

5 B s ^xxoW Fig 2 Rectified data for peak I of CaF2Hn

- H -

XXmxKT Fiji i Rectified data for peak II of CaF2Hi

0

5 gt c -5

-raquo

-15

1

bull bull bull bull bull bull bull

- bull bull

bullbull bull bull bull bull bull

bull bull

5 IB 17 IB 19 20 2 XXOJxW

Fif 4 Rectified data for peak III of CaF2Mi

- 1 5 -

Fowler

Would the atteapt-to-eseape frequency really be spuriously increased i f the heating rate were so nigh that several true peaks only appeared as one Is this in the right direction Surely Dr Horan said that he obtained s = lo (which i s too high to be reasonable) when his peaks were narrower than expected from simple theory

Adam

I do not think that there is a direct connection between the peak width and

the frequency factor so that one could not say offhand what will be the effect

of widening the peaks on the frequency factor

Mason

In the second slide yon determined E and s from a central portion of the

curve Did you try to determine E and s from the cxtieme parts of the curve

Adaa

Tes we did sone hand calculations but the results were nonsensical

Attix

Did you study natural fluorite or CaF-iMn I believe i t must have been the

fluorite but your t i t l e erroneously specifies CaFgiHn

Adaa

MBIpound gave us the dosimeters saying that the powder within was Caf2lfn If

however Dr Attix says this is their natural fluorite he is probably right

- 16 -

Investigation of

TtTnTrttradeilsclaquollt lithium Borate Classes

using Electron Spin Resonance

by

Douglas ampbull Shearer

Physics Departaont

St Bartholomews Radical College

London

The trapping centres involved in the theraoluminescence of lithium borate glasses have been identified as holes trapped on bridging and non-bridging oxygens in tfca glaa matrix The results of isothermal annealing experiaents indicate that the untrapping process occurs over a continuous spectrum of activation energies The radiation induced 8SR signal froa the glasses with a high alkali content decays fastest except for the anoaalous behaviour of the pure borate glass in which the signal disappears rapidly at room temperature The addition of aanganeae chloride increases the decay rate and reduces the number of trapped teles Manganese occurs in two sites in the glass lattice and their is evidence of this in the thermoluminescent spectrum This spectrum can be altered by the addition of other activators Heavily manganese doped glasses exhibit an additional glow peak at a higher temperature This has been assigned to the transition

Hn + e ^ Mn + hr

which occurs on post irradiation heating

A model has been proposed for the thermoluminescent process in these glasses and some suggestions for the improvement of crystalline lithium borate phosphors have been advanced

Present address Physics Department St Williams Hospital Rochester Kent

- 17 -

There axa aall daflaad probleaa to aolve la tho invntigation of any thaiaalmdashImanaat aubstanoe tha nature and anatier of the trapping and lierlnoananno centraa (anion aay ba aynonyaoua) Bust bo detemlned The kJnetiM leading to the oaiaBlon ara alao isttwrtant Zlntron spin reaonanm la a uaefal tool for laveatigatlBg tfaaaa paranatallaquo In the aaaa of the llthiun Borate group Irradiation Inlnoas a signal ahloh e n ba eoally followed The ouatonr ntivator - divalent bullangenaae - la a paraaagaatla elaaint nhioh giTea a characteristic signal Lithium borate l taalf la atndiad aoat easily orar a aide range of ooaposltlon In tha v i t -reoua atate

PMaauniar

a l l the axperlnantal glaaaea were prepared fraa Analar and Furlaa grade raagaata In a platlnun cro ib lo The firing teaparature aaa 1000degC Mangnnaae and other iasuritlea wars added aa chlorides nitrogen was paaaad through the furnace to ainlniae the quantity of trivalent aanganaaa preaent in the glass All glasses sera aaenohed in eater after 30 aia-ntes in the fornaee

For ESR work the glasses were le f t aa small chunks but for theraoluojlnoanenno atadiea the glass was groand and alaTad to a grain aiae of 80 - 160 aeah 15 aeV aleotrona fran the linear accelerator at St Baiifaoloawwa Hospital ware and for al l tha agpsrlnaatal irradiationa Tha Mcondaiy asiasion monitor deacribed by kotblatv vaa used for the dose callhrationa

Tor a Tslld ooaparlasn of signal helghta f isa different glasses a l l signal heights vara aoml i sed to that of a ruby standard Boosted on tha ooapnaetiag tabe TMa la essential for the range of glasses studied here u dleleotrio I o n la the high alkali oxide glaaaea oan rsdaee signal height by over $0JC The aenaltiTity of tha apeotroaeter vaa aaaaaaad using a known quantity of DPPH la bauana and employing tha standard double inteshygration aethoda auanrised by Poole

ThsraolaaiaeaooBt apsotra vere deterained using the apparatua dee eribad by Harris A Jackson3 anion has a range of 200 - 600 an The appshyaratus desorlbed by Xarsaark at al waa and for a l l quantitative therao-luaiaeaoence Fits to the varioaa kinetics expressions sera done using a IOT-8 ooaputer with a W ferri te core aeaory store

TRArrMJK CHUMS

Ina 13B signals from lrradisted llthlua borate g leans are as bullbona In yig 1 Ths top eight algaals are the original radiation induced spectre The bottom signal i s that mainng after oaraful aonallng

The overlying J and 4 peaked signals havs bean attributed by Grisooa at al to a centre oonaletlag of a hole tiappad on an oxygen bridging between lame and four oo-ordineted borons la the glass structure

The Haailtooian suggested by the above authors for tha structured algnal I s

- 18 -

faring = BCgSH bull g S 2 H 2 bull g SjHj) bull ASI bull A J S J I J bull ASjl 3

with g amp A valnes which wary with eoapoaition

The underlying signal has not baan as thoroughly investigated but i s baliarad by some workers to oe due to holes trapped on non-bridging oxygens

The number of trapped holes i s a function of eoapositiont dose temperatur and raquotorage t iaa The signal i s seen to decay at a l l temshyperatures dona to 77TC - the loaaat investigated I t seems likely that there i s a oontinnous apeotrua of activation energies for the untrapping prooass

Growth curves for the signal are shown in Hits 2 3 The effect of decay i s seen in the difference between tha r i t ive positions of the curves at 7 7 and room temperature

The curves saturate at about 2 x 10 rad when the number of trapped holes i s of the order of 5 x 10 ee after 24 hours s t 77 K Ins number of trapped holes i s independent of pro-irradiation and annealing (See Flit a) This indicates that the traps are not radiation induced

The rate of decay la composition dose and temperature dependent The decay rates of the low alkali oxide glasaes (with tha exception of the pure borate glass) ars least (Pie 5 ) The pure glass deoays rapidly at room temperature The high dose signals decay relatively faster (see Fig 6) Decay curves cannot be fitted by simple 1st or 2nd order expressions However an expression equivalent to that proposed by aedllm for theimo-lominsseent daoay from lerela with a distribution of activation energies gave reasonable f i t s (Pigs 7 8)

T^TwwanwjcE CHTTBES

The usual activator - divalent manganese - gives an E3B signal whieh variea with bass glas- composition and manganese concentration The -iinclaquoTrmdash ion i s more stable in tha lower alkali-oxide glasses (table I )

TABIE I

Intenaityunit sample mass

Intensity manshyganese atom

11

101

1001

12

098001

156002

HJ

097002

231005

14-

1707

5321

15

1501

578035

01

348011

24700

There ara two signals one at g a 2 and the other at g a 4 3 The g bull 2 signals for KT ga mole are shown In Pilaquo 9 Tha change in the g bull 2

- 19 -

aigaal for iaenaaiag aanganeae oancantxation la ahorn in f i n 10 Ina loaa la raaolution af tb hyperfiao atructure at higher eoneentrationa ia dna to dipolar broadening Iha g bull 43 aigaala ara aboan in gtilaquo 11 bdquo A Haalltnnlan for tte g laquo 2 aignal haa baan pmpoaad by Bleaney Snbina i o

^bull-B8JJsect+D[sI2-JS(S1)]AJS-08HJ for S- l - |

a Kadaie et a l baja giaan a HaaUtonian for tha g gt 43 signal produced by iaoalaetnniSfa in lithlua ailioata glaaaea Thia haa been appliad by Lunter et a l to aanganeae in aoaa glassy aatrieea i e

(^f-eBH-S + AVs1 for l - f s -J g-4-3 A- S

These aigaala hare bean attributed to aanganeae in tao different aites in the glass l a t t i ce The doainant g raquo 2 signal oorresponda to aanganase in an axially ajaantile alta The aigoal at g = 43 i s aaaosiated with rhonbio ayaaatry The tao aites concerned oan be tentatively identified aa aanshyganeae in netwoik aodifying and network foraing poaitiona

Carina oopper and iron have also been added aa obloridea The only ESR aignal raquoas aaen at g s 43 froa iron Thia haa been attributed toferric iron in aa orthorhoabio eleotroatatic crystal field (Caatner et

MB tTTECT Cf BAPIATigi CH THE ESB SIMM HOT DOFSB 6IASSTS

I t ia found in these glaaaea that the nuaber of trapped holes after irradiation i s l e ss than in the undoped glasses - the greatest decrease being Man in the glasses with tha suet added iapurity (Pine 12 H i

12 Theas results are ooapatible with those obtained by eriaeon et al which ahoa that halogen Vk oentea ooapote for liberated holes with the boron oxygen centrea thua raduajtng the oharactaristio alkali borate radiation indooed signal The rata of decay of tha aigaal ia also increased in the doped glaaaea (Flu 14) Thia will also decrease the effective nuaber of trapped holea

THMifllfflllaiBBfflWT SPBCTBA bull

Tharaolnminaaeont apaotra have bean obtained froa pure and doped glassee The nonaotiTated glass spectra are siailar to those of the nore lightly aanganeae doped glaaaea Thia iarliee that lualnesoeaoe in undoped glaeaea ia due to traoea of aaaganeaa These spectra peak at approziaately 620 an The spectra were aubatantially the sane for tha two hole traps which ladieates that the lnainosoonoo oentre la the sens ia both cases Within tha l i a l ta of tha experlaant no dependence of tht apaottua on dose w observed The tbtraolualneaoent apaotrua aoved towarda longer wavs-langtbe tin greater the oonoentration of aanganeae Aring aubaldlary feature la tha apeotruB of tha pure lithloa borate glassea waa a aaall peak at about 47$ an ( f lu 1Sgt which waa aore obrlotlaquo In tha lower alkali oxide glasses la addition the pore 01 glesa aotivated with 10 ga nole aanganeae showed

a peak at 5J0 an In the 15 glass doped with 1 0 ^ ga BO another aaall peek ma observed at 220 mu Thia caa only visible on to lag aeala ( H g l l f i ) Theaa apeetra a n raquolightly twperature dependent -the emission shifting towards the shorter wevalengtha on inorease of tea-perature (Table I I )

TABLB II

^ ^ S l a a a Temp Coapositien Bang

Peak(au) 77degK^Eooa leap

With (an)

Peek(att) Eooa Temp- 200 C

Width(au)

bdquo Fek(mu) 200 C-raquo laquo raquo C

fidth(mu)

11 lO

615plusmn15

550-710

610+10

5VO-700

61010

535-700

12 10-

620+10

560-700

615+10

560-690

63020

$20-690

13 10

640+10

570-710

6305

570-695

14104

6W+10

535-720

6305

575-710

625+5

570-700

15 10

61010 (5 tr -70O ( Peaks (A B C 6gtraquolaquo0-C70

615 10

555-710

610 5

55-695

01 10 -

6105 ( 5 0 laquo 7 5 ( Feaka ( A B (530~laquo5

610 5

560-675

610 5

560-680

J3 10 4 It baa keen shown (Blnghsa Parka tanter at al ) that the aaiasion peaking at -620 an ia aasoaiatad with nangsneae in ootahadral coshyordination alille manganese In tetrahedrally sjenil i lo surroundings gires rige to a green emission (approximately 530 an) I t has alao been noted (tajl 7 that the orange emission ia omenohed at higher teaperatores while the green ia relatively unaffected Thia amy explain the temperature effect aeon in the apaetxwa of swat glasses

the predominant emission at about 620 an and the 530 an amission hat been explained (Kedlin1 Bingbam 4 Parka1 ) as due to the K^ (T J laquo Ss (A1J tranaitlon - the differenoe ia wavelength being dna to the ayueetry change There ia a probability of the 4 (T ) - 6pound (AJ

transition abieh oould gire rime to the obserred emission at about 450 an -the higher lerels giring rise to the shorter warelength emissions

(Fin 17V (Curiatrade)

Whan doped with oeriua and upper the spaotrua ia altered aa shown The blue luminescence for oeriua at 385 au ha been attributed

to a transition between the doublet levels

S ^ ^ 1 7 Konoslent oopper i s reported (Xarapetyaa1) to give an emlaaion about 500 an and the sbsense of any 18H apootma n infonea this olusion The sopper apeutium ia extremely tmdashporalius dependant

at

- 21 -

Bassilaquo The tiieraoluainBscent eaiasion oan be examined aa a function of

SSJt signal height by step annealing individual glass saaplaa The resultant plot la not completely linear in a l l oases This i s not surshyprising in view of the tao contributory traps and the spectral shift with temperature Plots for two glasses are shown in Fine 18 19 The relationship i s significant enough however to assign the glow peak in these glasses to the hole traps observed by ESR

The glow curves are shown in f i g 20 Data are given in Table III

TABIB III

bullmdash__Jgtoae Composition mdashmdashmdash^

deg2 B2 deg3

L 02 BjOjIO- ga Vole lb

10 - 3 bull

102

101

107rada

190 + 8

200 + 8

141 8

Low tamp High temp 150 + 8 278 + 8

Low temp High lamp 138 + 8 265 + 8

106rado

168 + 8

163 + 8

1 laquo + 8

lO^rada

168 + 8

155 + 8

155 + 8

138 + 8

lO^radt

150 + 8

150 + 8

157 + 8

I t can be seen that increasing manganeae concentration gives riae to a higher temperature glow peak After irradiation these glasses have a purple t int due to Kn Tola disappears at the higher glow peak tempershyature The peak may therefore be correlated with the transition

e + Hh - gt bullraquo + hv

The actual glow peak temperaturaa are dependent on composition dose time and temperature of storage

Tiieraolumlneseent response eorvea are ahown in Elg 21 These are for undoped glasses The low responses for the BjO and UJOBJO glasses are due mainly to the laek of trapped holes With the addition of 10 ga bullale manganese la each glass the results are aa shown in Fig 22 These results oan partially be explained by better activator efficiency and trap stability in the low alkali oxide glasses The response curves for the _ manganeae activated 12 glasses are shown in Tie 23 The peak for the 10 ga mole activate glass sen be explained as the beet compromise between number of effective activator atoms and number of trapped holes The resshyponse curves due to the other aotivators am as shown (Jja_2a) The

- 22 -

increased responses due to oopper and oeriun are primarily due to tho change In emission speotra That tho above considerations ara not tho whole story la shows by Fin 25 l raquo tho number of observable trapped holes and luminshyescent centres do not entirely determins tho thermoluminescent outputlaquo Con-oantration onenohing meohsnisms are almost oertslnly involved in tho more heavily doped glaases and difforaneoa in energy tranafar propertiea of the base glosses may be important

MODEL FOB THgarcmimiBscmcK

Ihe above experimental data lead to a Model with at least tao hole traps These trapa hare a distribution of aotiTation energies The traps are not dependent on radiation formation added impurities provide additional trapping oentraa The lnadneaeent centre i s independent of the trap and the Mission spectrum can be altered by changing actiTators So far i t haa not been possible to determine whether eleetrona or holes are entrapped but a simple model assuming electron unt rapping i s shown in Pilaquo 26

The high tempersture peak in the heavily manganese doped samples can be pictured aa a result of the prooees shown in Fig 27

COHCUBICBS

From the sbcTe data it would aeea that the most efficient manganese activated phosphors are those in which the alkali oxide content i s ss low ss possible and which are prepared under reducing conditions As halogens appear to be responsible for decreasing the number of useful trapped holes the manganese should not be Introduced as the chloride Manganese acetate would serve Urn purpose of eliminating the competitive traps I t would also help to reduce the manganese to the divalent state

Preliminary preparations of crystalline lithium borate phosphors have been carried out along these l ines with good results

An sltemative method of increasing the effeetive effioienoy i s to shift the emission spectrum This can be achieved by doping with activators giving emission spectra in the shorter wavelength region

As the ISR signals from orystals appear substantially the same work i s being carried out to extend these ideas to the range of eryatalline phosphors

- 23 -

REFERENCES

J Rotblat Natura (London) 175 745 (1955)

CP Poo llaquo Electron Spin Reaonance ( i n t e r a e i e n c e ) (1967)

AB Harris 4 JH Jackson CEGB Report RDB1I111 (1968)

CS Karimark J I h i t a and J F Fowler Phys Med B i o l 2 273 0964)

P Beekenkanp P h i l i p s Reaaarch Report Supplements No 4 (1966)

DL Grieeoa PS Taylor PF Ware A PJ Bray

J Chelaquo Phys 48 5158 (1968)

WL Medlin Phys Rer laquo3_ 502(1961)

B Bleaney A RS Rutine Proo Phya Soc JJ 103 (1961)

RW Kediie DH Lyona A Kestigian K Phys Rer 138 A(918) (19B)

SG Lunter C O Karapetyan NB Bokin A DM Yudin Soriet loyales - Solid State 9 2259 (1968)

T Ceatner G Newell N Holton A C Sliohter J Chelaquo Phys 2 668 (I960)

DL Griaeoa PS Taylor A PJ Bray J Chan Phya 50

977 (1969)

K Binghaa A S Parka Phyaiea A Cham of Glass 6 224 (1965)

WA Weyl Coloured Glasses (The Society of Class Technology)

(1951)

I L Medlin J Opt Soo Aner pound J 1276 ( 1965 )

D Curia Traquollaquo1neioenoa in Crysta l s llethuan A Co Ltd (1965) 0 0 Karapetyan IZT AKAD NAUK SSSR SER FIZ 2g 539 (1961)

- 2 4 -

RADIATION-INDUCED ESR SPECTRA OF LITHIUM BORATE GLASSES

i-tn MBi 2-WC 9

Fig 1

DOSE RES PONSE CURVES OF PURE LITHI UM BORATE GLASSES AT 77deg K

10 bull

sect W in bullI Vgt ui

i 3

Kgtl bull i i i W W raquo W TO

DOSE (RADS)

Fig 2

- 2 5 -

gw

DOSE RESPONSE CURVES Of PUK LITHIUM raquoCRA1E GUSSES

AT ROOM TEMPERATURE

bull 1 1

bull 1 = 2

3 - g i ^ ^

J ftr-

Fig 3

O Vira in FvwiMabJnatfiMi

i ^ S D

reg lslaquoUlaquo

4r

t

raquoraquo raquo 3 i OMflraM

raquo g

Isl IKRIVATIVE E S R SIGNAL HEIGHT

N0RMMISE0TO INITIAL HEIGHT

I l 4 DERIVATIVE E S R SIGNAL HEIGHT NORMALISED

TO INITIAL HEIGHT 9

I

I

- 2 7 -

CUttS M i raquobullbull

mon ranwruK KCAV OF cwrositwlaquo u t ^ ras n a i euss M S - raquo I gMOS t - a bull bull L I

nlaquo 6

- 2 6 -

UDft |01 la4RHgtMliHll _

si s- M

V R J O J IB gm bull Mn

T

|0raquo|0) bull bull - - bull bull bull bull bull -

n 9-

ESB WBWtKAT bull - FOD UIOLAW WHH raquo K B E N T FKOKRtTMM

M t c - m mdash raquo iju=o-raquo

^ A bull s

-

x ltraquoVn 1- HMlaquo Hu UfO raquo(DfUT1 ftlaquolaquo

ris lo

- 2 9 -

E8R S n i U k U A T f - 4 FC li 1 GLASS ACTIYATEDWITH DIFFERENT

- 3 0 -

ENfCr O ADOID WMKaringaringtM ON L M DQSf bull

laquornooM Jtmmmm

i

I I 1 sect 3 i

I t

l

i r B

I

ltt

rf laquo f

raquo

- tf

i f

i i 1 1 raquo raquo raquo

Fig 12

- J l -

IKICT V raquo i l v WEMHT ADHB ACTIVATOII ON I U OOU HMftWS OF I I CUtSSAT ROOM TWHUTUM

51 i 1

I K

Ml (raquobullraquogt

Pig 13

DECAY RATES Of IRRADIATED MANGANESE ACTIVATED 14 GLASS AT ROOM TEMPERATURE

1 Tzzia

k 2 I

KgtgmimhraquoMn

^

raquo-raquo

I Hi

MimrtH at M M tamp

f i 14

32

- 3 3 -

DOm WITH raquo - laquo raquo bull HOUt HAMCAHUI

bull jplusmnplusmnjraquojioiiiplusmn plusmn

ti- 16

- 3 4 -

Pig 17

PLOT OF LIGHT IN GLASS AS A FUNCTION OF 1st DERIVATIVE E S R SIGNAL HEIGHT

FOR M COMPOSITION

bullbullORONHTPERFINEFEAK

bullASYMMETRIC FEAK

bull bull I -J O gt 4 0 K 100

OF 1st DERIVATIVE E S R SIGNAL HEIGHT

Pig 18

- 3 5 -

n a OF LIGHT IN MASS AS A FUNCTION OF

MDOIIVATIVELSIL SIGNAIHEICHTFClaquo 15COMPOSITION

bull bullOMNHVFFJFIHEFEAr

bull ASVMCntlC PEAK

r

raquoCf lUOfHIVAI IVELS i l SIGNU WIGHT

Mg 19

CLOW CURVES FOR IRRADIATED III LITHIUM BORATE

Tig 20

UDC 53SS7-SXA2M

December 1971 RisS Report No 249 Part I (pp 1 -443)

Proceedings of the

Third International Conference on Luminescence Dosimetry

Held at

The Danish Atomic Energy Commission Research Establishment RisO

October 11 -14 1971

Sponsored by

The Danish Atomic Energy Commission

and

International Atomic Energy Agency

Editor

V Mejdahl

Abstract

Seventy-eight papers a r e presented from the 3rd International Conshy

ference on Luminescence Dosimetry The papers a r e arranged according

to the following topics Mechanisms of Thermoluminescence (TL) TL Inshy

strumentation Improved TL Materials Propert ies of TL Materials Thershy

mally Stimulated Exoelectron Emission Radiophotoluminescence TL in

Clinical and Personnel Dosimetry Dating and Background Radiation Monishy

toring Charged Part ic le Neutron and UVdeg Response Miscellaneous Propshy

ert ies Effects and Applications

ISBN 87 550 0120 3

ISBN 87 550 0121 1

FOREWORD

This publication presents the papers given at the third International Conference on Luminescence Dosimetry The papers reflect the extensive research and development that have been accomplished since the second International Conference on Luminescence Dosimetry held at Gatlinburg Tennessee in 1968 The great number of papers seventy-eight clearly Indicates the continuing interest in this field There were 144 registered attendees representing twenty-seven countries and three international orshyganizations Austria Belgium Brazil Bulgaria Canada Czechoslovakia Denmark Finland France Germany (DDR and the Federal Republic) Greece Hungary India Israel Italy Japan Mexico The Netherlands Norway Poland Portugal Sweden Switzerland United Kingdom U S A Yugoslavia CERN IAEA and WHO

In connection with the conference a commercial exhibition was arranged which snowed the latest developments of measuring equipment Eight comshypanies representing six countries participated in the exhibition

To enable rapid publication the papers have been reproduced directly from the manuscripts handed over by the authors A few papers were withshydrawn by the authors and in such cases only abstracts are given Discusshysion on a paper i s inserted at the end of the paper The publication i s in three parts Part I contains sessions I-V part H sessions VI-IX and part m sessions X-XU The grouping of papers into sessions appears from the l ist of contents which i s included in each volume

The assistance of Miss L Kristiansen Miss B Ramgill and the printing office staff in the publication of the proceedings i s gratefully acshyknowledged by the Arrangements Committee

V Mejdahl

CONFERENCE OFFICERS

Co-Chairmep

J F Fowler

Research Unit in Radiobiology Mount Vernon Hospital Northwood United Kingdom

A Scharmann University of Giessen Federal Republic of Germany

Programme Committee

K Becker Chairman

Oak Ridge National Laboratory U S A

FH Attlx

U S Naval Research Laboratory U S A

J R Cameron

University of Wisconsin U S A

J H Schulman Special Advisor U S Naval Research Laboratory U S A

Local Arrangements and Publications Committee

V Mejdahl Chairman Danish AEC RisB Denmark

CA Carlsson Vice-Chairman University of Linkfiping Sweden

L Boslashtter-Jensen Danish AEC RisO Denmark

E Pedersen

Danish AEC RisB Denmark

CONTENTS

PARTI

Page

MECHANISM OF THERMOLUMINESCENCE I Chairman S Watanabe University of Sao Paulo Brazil

Interpretation of Resolved Glow Curve Shapes in LiF (TLD-100)

from 100deg to 500degK EB Podgorsak PR MoranandJR Cameron 1

Analysis of Thermoluminescence Kinetics of CaFbdquo Mn Dosimeters

G Adam and J Katriel 9

Investigation of Thermoluminescent Lithium Borate Glasses using Electron Spin Resonance Douglas R Shearer IS

A Simple Thermoluminescence Model and its Application in Thermoluminescent Dosimetry R Abedin-Zadeh 41

Efficiency Variations of Thermoluminescent LiF Caused by Radiation and Thermal Treatments Per Spanne and C A

Carlsson 48

MECHANISMS OF TL II Chairman A Moreno y Moreno Inst of Physics Univ of Mexico Mexico

Continuous Model for TL Traps Shigueo Watanabe and Spero Penha Morato 58

The Influence of Hydroxide Impurities on Thermoluminescence in Lithium Fluroide L A DeWerd and T G Stoebe 78

Influence of OH Anion on the Thermolumiscence Yields of Some

Phosphors Toshiyuki Nakajima 90

Abnormal Thermoluminescence Fading Characteristics A G Wintte MJ Aitken and J Huxtable 105

Fading In Thermoluminescent Dosimetry Zdenek Spurny and Josef Novotny 132

Page

Effects of Deep Traps on Supralinearity Sensitisation and Optical Thermohuninescence in LiF TLD C M Sunta V N

Bapat and S P Kathuria 146

Supralinearity and Sensitization V K Jain and J B Sasane 156

Re-estimation of Dose in LiF G S Linsley and EW Mason 1 ST

Properties of Some Deep Traps in Lithium Fluoride- E W Mason and G S Linsley - 164

TL INSTRUMENTATION

Chairman T Higashimura Research Reactor Institute

Kyoto University Osaka Japan

Possible Elimination of the Annealing Cycle for Thermoshy

luminescent LiF G A M Webb and H P Phykitt 185

Significant Changes in TLD Readings Produced by AC Heater

Currents J E Saunders 209

Photon Counting as Applied to Thermolumiaescence Dosimetry

T Schlesinger A Avni Y FeigeandSS Friedland 226

Dosimeter and Reader by Hot Air Jet H Oonishi O Yamamoto T Yamashita and S Hasegawa 237

The Emission Spectra of Various Thermoluminescence Phosphors K Konschak R Pulzer and K HQbner 249

IMPROVED TL MATERIALS I

Chairman Z Spumy Nuclear Research Institute Prague Czechoslovakia

Some Thermoluminescent Properties of Quartz and its Potential

as an Accident Radiation Dosimeter D J McDougall 255

Thermoluminescent Enamels M Mihailovic and V Kosi 277

Thermoluminescent Phosphors based on Beryllium Oxide Y Yasuno and T Yamashita 290

A Study of Silver Iron Cobalt and Molybdenum as Lithium Borate Activators for its use in Thermoluminescent Dosimetry

A Moreno y Moreno C Archundia and L Salsberg 305

Page

IMPROVED TL MATERIALS II Chairman T Schlesinger Soreq Nuclear Research Centre

Yavno Israel

Sintered TL Dosimeters T Niewiadomski M Jasinska

and E Ryba 332

Studies of the Thermoluminescence of Lithium Fluoride Doped

With Various Activators M E A Robertson and W B Gilboy 350

A New TL LiF (NTL-50) Which is Unnecessary of Annealing

its Properties Especially for Application and the Results of Several Practical Cases Katsumi Naba 357

Thermoluminescent Response of Natural Brazilian Fluorite to 137

Cs Gamma-Rays S Watanabe and E Okuno 380 Thermoluminescence of Natural CaF~ and its Applications

C M Sunta 392

Improvement of Sensitivity and Linearity of Radiothermolu-minescent Lithium Fluoride G Portal F Berman Ph Blanchard and R Prigent 410

Further Studies on the Dosimetric Use of BeO as a Thermoshyluminescent Material G Scarpa G Benincasa and L Ceravolo 427

PART II

PROPERTIES OF TL MATERIALS Chairman C Carlsson Univ of LinkSping Linkfiping Sweden

Dose Relationship Energy Response and Rate Dependence of

LiF-100 LiF-7 and CaS04-Mn from 8 KeV to 30 MeV G Eggermont R Jacobs A Janssens O Segaert and

G Thielens 444

On the Non-Linearity and LET Effects of the Thermolushyminescence Response Toshiyuki Nakajima 461

On the Sensitivity Factor Mechanism of Some Thermolushyminescence Phosphors Toshiyuki Nakajima 466

The TSEE Response of Ceramic BeO covered with Different Absorbers During Gamma and X-Ray Irradiation E Rotondi and T Suppa 480

Low Temperature Monitoring Using Thermoluminescent Materials Robert D Jarrett J Halliday and J Tocci 490

Dependence of the Response of LiF TLD 100 Powder

Incorporated in Silicone Rubber on Grain Size P Bassi G Busuoli A Cavallini L Lembo and O Rimondi 504

Manufacture of Uniform Extremely Thin Thermoluminescence Dosimeters by a Liquid Moulding Technique Geoffrey A M

Webb and George Bodin 518 7

The Consistency of the Dosimetric Properties of LiF in Teflon

Discs over Repeated Cycles of Use T O Marshall K B Shaw and E W Mason 530

Influence of Size of CaFraquoMn Thermoluminescence Dosimeters 60 on Co Gamma-Ray Dosimetry in Extended Media

Margarete Ehrlich 550

THERMALLY STIMULATED EXOELECTRON EMISSION Chairman P Maushart Berthold-Frieseke Vertriebsgesellschaft GmbH Karlsruhe Germany

Exoelectronic Properties of AlgO-Solids G Holzapfel

and E CrysBou 561

Chemically Thermally and Radiation-Induced Changes in the

TSEE Characteristics of Ceramic BeO R B Gammage K Becker K W Crase and A Moreno y Moreno 573

Exoelectron Dosimetry with Oxide Mixtures M Euler

W Kriegseis and A Scharmann 589

Low-Z Activated Beryllium Oxide as a High Sensitive Radiation Detector in TSEE Dosimetry D F Regulla G Drexler and L Boros 601

TSEE Dosimetry Studies T Niewiadomsld 612

The Optical Stimulation of Exoelectron Emission J Kramer 622

Page

Characteristics of Selected Phosphors for Stimulated Exoelectron Emission Dosimetry P L Ziemer W C McArthur V L McManaman and G D Smith 632

Problems in the Use of Proportional Counters for TSEE Measshyurements L D Brown 654

Trapping Centers in CaF2Mn from Thermoluminescence and Thermally Stimulated Exoelectron Emission Measurements on Undoped and Mn Doped CaF Samples K J Puite and J Arends 680

RADIOPHOTOLUMINESCENCE

Chairman K Becker Oak Ridge National Lab

Oak Ridge USA

Formation Kinetics of Color Centers in RPL Glass Dosimeters

AM Chapuis M Chartier and H Francois 692

A RPL Dosimetry System with Fully Automated Data Evaluation M Dade A Hoegl and R Maushart 693

New Type of High-Sensitive and Soil-Insensitive RPL Glass Dosimetry R Yokota Y Muto Y Koshiro and H Sugawara 709

Laser Pulse Excitation of Radiation Induced Photoluminescence

in Silver-Activated Phosphate Glasses F Hillenkamp and D F Regulla 718

The Response of Radiophotoluminescent Glass to Co Y-and 10-30 MeV Electron Radiation L Westerholm and G Hettinger 727

Some Ways of Applying the Capabilities of Various Luminescence Methods in Personnel Monitoring M Toivonen 742

Radiation-Induced Optical Absorption and Photoluminescence of

LiF Powder for High-Level Dosimetry EW Claffy SG

Gorblcs and F H Attix 756

Page

TL IN CLINICAL AND PERSONNEL DOSIMETRY Chairman F H Attix U S Naval Res Lab Washington DC USA

Two Years Experience of Clinical Thermoluminescence Dosimetry at the Radiumhemmet Stockholm Bengt-Inge Ruden 781

Thermoluminescence Dosimetry for Clinical Use in Radiation Therapy D S Gooden and T J Brickner 793

TLD - Calcium-Fluoride in Neutron Dosimetry TLD -Calcium-Sulphate in Health Protection Service D K Bewley and pound Blum 815

Lithium Fluoride Dosimeters in Clinical Radiation Dose Measureshy

ments N Suntharalingam and Carl M Mansfield 816

A Personal Dosimeter System Based on Lithium Fluoride Thermoluminescent Dosimeters (TLD) A R Jones 831

Progress Towards Automatic TLD Processing for Large-Scale

Routine Monitoring at RisB Lars Boslashtter-Jensen and Poul Christensen 851

UV Induced Thermoluminescence in Natural Calcium Fluoride

Emico Okuno and Shigueo Watanabe 864

A Current Look at TLD in Personnel Monitoring F H Attix 879

PART m

DATING AND BACKGROUND RADIATION MONITORING Chairman M Aitken University of Oxford Oxford England

New Techniques of Thermoluminescent Dating of Ancient Pottery

I The Substraction Method S J Fleming and D Stoneham 880

New Techniques of Thermoluminescent Dating of Ancient Pottery

II The Predose Method S J Fleming 895

Progress in TL Dating at RisS Vagn Mejdahl 930

Some Uncertainties in Thermoluminescence Dating Mark C Han and Elizabeth K Ralph 948

Environmental and Personnel Dosimetry in Tropical Countries Klaus Becker Rosa Hong-Wei Lu and Pao-Shang Weng 960

Natural Radiation Background Dose Measurements With CaF2Dy TLD D E Jones C L Lindeken and R E McMillen 985

Impurities and Thermoluminescence in Lithium Fluoride MJ Rossiter DB Rees-Evans and S C Ellis 1002

CHARGED PARTICLE NEUTRON AND UV RESPONSE Chairman N Suntharalingam Thomas Jefferson University Hospital Philadelphia Pennsylvania USA

The Measurement of Dose from a Plane Alpha Source J R Harvey and S Towns end 1 015

Thermoluminescent Research of Protons and Alpha-Particles

with LiF (TLD - 700) B JShnert 1031

Thermal Neutron Dosimetry by Phosphor Activation

M R Mayhugb S Watanabe and R Muccillo 1040

Determination of the Sensitivity of the CaF2Mn Thermoshyluminescent Dosimeter to Neutrons M Prokic 1051

Triplet Exciton Annihilation Fluorescence Changes Induced by

Fast Neutron Radiation Damage in Anthracene D Pearson P R Moran and J R Cameron 1063

Mixed Neutron-Gamma Dosimetry S K Dua R Boulenger

L Ghoos and E Mertens 1074

Energy Response of Certain Thermoluminescent DosimeterB

and Their Application to the Dose Measurements H K Pen-durkar R Boulenger L Ghoos W Nicasi and E Mertens 1089

Tm-and Dy-Activated CaSO Phosphors for UV Dosimetry

K S V Nambi and T Higashimura 1107

Transferred Thermoluminescence in CaF~nat as - Dosimeter of Biomedically Interesting UltravioletRadiation Edwin C McCullough Gary D Fullerton and John R Cameron 1118

Page

MISCELLANEOUS PROPERTIES EFFECTS AMD APPUCATIONS Chairman H Francois C E A Paris France

Storage Stability of TL and TSEE from Six Dosimetry Phosphors AE Nash VH Ritz andFH Attix 1122

Optical Absorption and ESR Properties of Thermoluminescent Natural CaF2 after Heavy Gamma Irradiation Ks SV Nambi and T Higashimura 1155

Methodological Aspects on Measurements of Steep Dose Gradients

at Interfaces Between two Different Media by Means of Thermoshy

luminescent LiF Gudrun Aim Carlsson and Carl A Carlsson 1163

Kapis as a Thermoluminescent Dosimeter N T Bustamante

R Petel and Z M Bartolome 11 77

Experimental Modification of Thermoluminescence by Static and Explosive Deformation D J McDougall 11 93

Some Dosimetric Properties of Sintered Activated CaFlaquo

Dosimeters D Uran M Knezevic D Susnik and D Kolar 1195

Panel Discussion 1209

Author List 1217

List of Participants 1220

List of Exhibitors 1229

1 -

Interpretation of Resolved Glow Curve Shapes in

LiF(TLD-100) fron 100deg to 500degK

by

E B Podgorsak P R Horan and J R Caaeran

Laboratory of Medical Physics

Physics Department and Radiology Department

University of Wisconsin Madison Wis

Abstract

We note that each glow peak of LiF(TLD-100) in the temperature range

from 100deg to 500degK displays a shape peaking temperature dependence on

heating rate and lack of peaking temperature dependence laxm total light

output whidi are in detail as predicted by the most simple thermally

activated kinetics in the f irst order Randall-Wilkins limit We also

note however that the glow curve breadth is anomalously large at low

temperatures and anomalously small at high temperatures While physically

reasonable although improbable mechanisms might explain the larger

breadths there seem to exist no physically reasonable direct mechanisms to

explain the narrower breadths We propose an indirect explanation in which

the activation energy i s i t s e l f slightly temperature dependent We discuss

how this effect explains the observed results and speculate on other

implications

2 -

Introduction

Since cur abstract was submitted a detailed description of our experi-aents relating to correlations in glow peak behavior from 100 to S00K has been published1 We therefore wish to discuss here primarily an intershypretation of resolvable glow curve shapes and apply these results to the TLD-100 observations Figure 1 shows the ten glow peaks we have studied glow peaks (-1) and (-4) are not optically repqpulated with uv irradiation and this allows us to resolve die details of peaks (u) and (-3) These glow curve shapes each exhibit a 501 half-breadth asymmetry on the law temperature side and at a given heating rate neither the peaking tempershyature Tn nor temperature breadth A depend upon the peak TL intensity This behavior characterizes first order kinetics and consequently we discuss here only the Randall-Nilkins description although our results can also easily be applied to die Garlick-Gibson limit A particularly intershyesting feature is that all glow peaks in this temperature range ham essentially die same temperature breadth 4 = 20 2degC

Glow Curve Behavior

It is not appropriate to pursue all mathematical details here but a brief review of die first order kinetics of thermally activated mechanisms is useful The concentration of trapped charge carriers n corresponding to a single resolved glow peak obeys die relation

raquof-Kn (1)

where w is an activated rate function

laquo bull se-W (2)

and die TL intensity in the simplest case is some fraction of die release rate

I(t) = -cSjn (3)

The above equations can easily be integrated formally one can obtain from diem an implicit expression for die peak temperature

(Eky bull logCEky log is^Ty 1 (4)

When die glow curve is narrow AlaquoT i t is not difficult to show diat

(Ekyraquol (S)

and Eq 4 can be validly approximated as

(Ery - logis^Ty 1 (6)

Me shall return to die expression in Eq 6 later

For narrow glow curves one can also show that analytic expressions can validly be used to approximate die integration of Bqs (1) - (3) The result is

I(laquoT) - bdquo expl bull (6Ty (Eky -exp[(STy (Eky] (7)

- 3 -

where 4T i s the departure from Ta

laquoT = T-Tbdquo (8)

Figure 2 shows the predictions of Eq 7 compared to the experimental glow curve for peak (-3) peak (-3) i s chosen because i t i s the fractionally broadest glen peak and therefore tests our approximations most severely Me note die characteristic tSOt low temperature asymmetry and that the nuaerical result for the glow peak breadth at half-aaxiaua i s

A = ( 2 4 4 ) 0 ^ ^ ) TB (9)

One can now use Eqs (9) and (6) together with die experimentally observed TB and amp to determine E and s There are of course other methods as well but they give similar results and Eqs (9) and (6) most directly illustrate die effects we wish to point out

If we examine glow peak (-1) which has TB 267degK at our heating rate of 35degKmin we find

E(-l) = 76 eV (10a) s ( - l ) = S x 1012 sec1 (10b)

This value for s is to be expected i f die trapped carrier interacts as strongly with neighboring ions in die solid as die ions do with one another die s is die limiting attempt frequency and must be approximately equal to the typical DeBye lattice vibration frequencies These frequencies are indeed about 5 x 1012 s ec 1 for LiF If on the other hand we examine glow peak (-3) we find

E(-3) - 028 eV (11a) s(-3) 107 sec1 (lib)

12 -1 Expressed another way i f we assumed s(-3) = 10 sec tiwn die breadth of peak (-3) is about a factor of two broader than predicted Many explanations have been put forward to explain such anomalously large breadth of glow peaks For example fliere might exist a spread in actishyvation energies E or die trapped carrier might somehow be effectively insulated from die lattice vibrations or there might be overwhelming retrapping effects to effectively reduce die net attempt rate

Finally let i s examine glow peak (5) which has been extensively studied because of i t s use as die primary dosimetry glow peak Here we find not an anomalously large breaddi but an anomalously narrow breadth While i t i s not difficult to give plausible mechanisms to broaden a l ine i t i s very difficult to propose narrowing mechanisms The parameters determined are

E(S) - 22 eV (12a) s(5) laquo 1023 sec1 (12b)

Similar results are also obtained by measuring die logarithmic change of Ta as 3tT i s varied widi an analysis according to Eq 4

The point we wish to emphasize i s that while reasonable although

- 4 -

peihaps unlikely explanations can be Bade for s raquo 10 in glow peak (-3) there exists no simple physically reasonable mechanism for an actual s - 1 0 in peak (S) because this i s a factor of at least 10l larger than the limiting lattice interaction frequencies in the solid

He have found that we can resolve these difficulties siaply by assuming that die activation energy E i s very slightly temperature dependent ke will not present die detailed mathematics here but the following results are obtained

1 Mien an observed glow peak i s narrow 6laquoT_ then a simple analytic approximation i s always valid in integrating the kinetic equations Eos ( l ) - (3) this includes the possibility of a temperature dependent activation energy The most important relation i s

w(T)dt = wp T)1 [ariogw]1 C13) o

2 The resulting glow curve descriptions have exactly the same form as Eqs (4) through (9) except that E and s are replaced by the parameters E and s where

E - ftSOslashECBUlftg (B - 1kT) (14a)

s - expCtE-ECyikys (14b)

3 In Eq 6 the difference between E and E(T) i s exactly balanced by the difference between s and s 4Thus Eg 6 remains valid independent of whether one uses E and s or E and s

4 For glow peak (5) a slight increase in E with temperature amounting to a fractional effect of less than 10~3 (K1) easily accounts for the anomalously narrow breadth and gives a n s = 1 0 resulting from an actual interaction rate of s - 1012

5 Ml other aspects of shape breadth peak height behavior etc are preserved according to the basic Randall-Wilkins results

As a final speculation we propose that other slight temperature deshypendences account for a l l anomalous breadths For example one need not invoke the somewhat unlikely existence of dominating raquotrapping terms to explain the large breadth of peak (-3) since only a small temperature dependence of E provides the same resulting behavior

He can also speculate further on die E vs E behavior l e t us suppose as a very crude model that a l l glow peak traps are roughly the same character for example basically a weak coulomb-like binding stabilized by the surroinding ions As die temperature increases from 0K die lattice undergoes tfiermal expansion He might expect diat die trap depth wi l l f irst increase due to die reduction of die neighboring ion repulsive potentials and with continuing temperature increase die binding wil l eventually begin to decrease due to reduction of the Coulomb attraction Thus die fractional temperature dependence of E for each glow peak would show leading term of the form

- 5 -

E - E A ( l a T - BT2) CIS)

which can be rewritten

E bull Eo(l - b f f - y 2 ) (16)

We think i t i s interesting that by choosing b bull 10 (K) and T - 300K we can f i t a l l the observed clow curve shapes while retaining a single activation frequency s - 1012 sec1 characteristic of lattice vibration interactions and negligible retrapping

References

(1) E B Podgorsak P R Hsran and J R Csjeron JAP 42 2761 (1971)

(2) P R Koran E B Podgorsak USAEC Report COO-1105-164 August 1971

IMs wort wis supported by the United States tonic Energy Agency and by the (ltS nir Force Office of Scientific Research

- 6 -

I I I i i mdash I mdash I 1 1 r i

Eacute 8 8 8 8 8 5 8 8 2 ni) aiuwraquo iron

Tmdashimdashimdashimdashimdashimdashr

SO -40 -30 -20 -10 0 ST-(T-Tmax) [degk]

Figure 2 Glow peak (-3) of LiF(TLD-100) The dotted curve is calculated from Eq 7 and the undotted line is the experimentally measured glow curve

Fowler

Tour explanation of a too narrow peak in terms of a dependence of activation

energy on temperature is Interesting How did you come to this conclusion

What physical processes could lead to such a dependence and are the orders

of magnit ie involved reasonable

Moran

First we looked for a single explanation which could give low-temperature peaks a too large breadth and high temperature peaks a too small breadth At least for low Irradiation levels in l iF (TLD-Ioo) a reasonable single explanation wlaquolaquo~ E = E(T) A possible physical process i s suggested in the written version of thiB paper we suggest that thermal latt ice expansion can give a fractional variation of the form

B(T) = E (1 - b(0Wr )2gt o o By choosing bo-lO-7 C^)2 and If- 2$0degti we can f i t the 0^ and o of a l l LiF (TLD-IOO) strong resolvable glow peaks using only a strong-coupling

12 -1 lattice vibration interaction frequency s = 5x10 sec bull

Analysis of Thermoluminescence Kinetics of CaFMn Dosimeters

n Adam and

T Katriel

Nuclear Research Centre - Negev PnB 9001 Beer - Sheva Israel

Abstract

A new approach to the analysis of glow curves is used to study the

kinetics of the tnermoluminescence of Cal iMn dosimeters Activation

energies frequency factors and related parameters are obtained The

measurements were carried out on the MRLE themoluminescence dosimeters

using a PNH 80] reader in the temperature ranfes 300 - 700 degK The

computational aspects of the analysis are discussed and the computer

program performing the entire analysis using as an input the glow curve

data i s described in the appendix

Introduction

The analysis of thermoluminescence glow curves is a conventional

and powerful method for the determination of activation energies

frequency factors and related kinetic parameters for the processes involved

A new method of analysis has recently been suggested by Haxia e t al

who also applied i t to the thermoluminescence of ZnS and NaRr The glow

curves involved consist of single peaksTt is interesting to apply the

method to a more complicated glow curve The despread use of die

MBLE CaF2Mn dosimeters which have three peaks in their glow curves

as well as the ease with which their glow curves are obtained by use

of the commercial reader made them a suitable example for the present study

Description of the Method

The kinetic equation governing the light emission during a themc-

-luminescence transition is assumed to be

-dnjdt - sexpC-KkTHBjimiVtACN-n^Biiijl (1)

where

m Ccm) is the concentration of holes lying in the ith type luminescent

center

s(sec ) is the frequency factor

E(eV) is the thermal activation energy

A and Bj (cm sec1) are the probability factors respectively fbr

raquotrapping and recombination with the ith type center

N(cm~) electronic trap concentration

n(cm3) i s the trapped electron concentration

k is the Boltxman factor and T the absolute temprature

From this equation the following equation for the line shape of the

glow curve was developed in ref (1)

iog[irr)(cose bull sinescm(s2(T) bull asm)] bull -ECT bull y (2)

I(T) being the intensity of the emitted light at temperature T raquo Tfinal

A laquo I(T)dT and S(T) bull I(T)dT 0 and u are constants Tfinal T

related to the kinetic parameters For the correct value of 6 eq(2)

expresses a linear dependence of

y bull log[t(T)(cose bull sinBS(T)V((T) bull AS(T))] on x - 1T

The numerical analysis involved in obtaining the proper value of 9 is

described in ref (1)

bull A typographical error was noted in eq 23 of ref 1 This equation

should read B bull -keov(xy)v(x) - -kv(y)cov(xy)

- u -

After the right value of 0 has been obtained the activation energy

and the constant u are determined from the slope and the intercept

respectively of the linear curve The ratio AB and the frequency factor

are expressed in ref (1)_ in terns of these partmeters

Measurements and Results

As was noted above the investigated sample was CaF tMn in the form

of a thermoluminescent dosimeter type PNP 292 produced by MBL

The dosimeters were irradiated by an X - ray machine with a maximum

energy of 45 JteV to a dose of about 1000 R The dosimeters were then

heated using the MRLH thermoluninescence dosimeter reader type PMH 801

from room temperature to about 700 K The heating rate i s 45 per

second The glow curves were recorded during the heating period using

a special output provided in the reader The points on the glow curve

were then used as an input to the computer program described in the

appendix the intensity being measured in arbitrary units and the tenprature

in degrees centigrade The rectified data i s represented in figs 23 4

The obtained results are summerzed in the following table

peak I

peak IT

peak III

activation energy eV

120

165

169

peak temp

382

447

536

frequency factor s

S9810

tnW1

414laquo10

AB

237

599

703

The first peak has a particularly low activatio energy which is compensated

with a low frequency factor The roles of the activation energy and the

frequency factor in defining the peaks tenprature can be judged fro

1 2 -

the relation

Esexp(-EkT) - C

where C is a constant depending on som general characteristics of the peak ~

and T is the temperature at the peaks maximum This relation is derived

froa eq 11 of ref 1

Appendix Description of the Computer Program

The glow curve data is introduced as a set of valuesof the emission

intensity versus the corresponding temperatures These are represented

as a linear combination of a few Gaussians in the form N

I(T) x T Ciexpt-OitT-ti)2] = CTf (3) W

The non - linear parameters [ a^t^l are varied in order to optimize

the representation The vector of linear parameters i s obtained as M M

C - S - v where S^ bull T fiCTk)fj(Tv) and Y j - T ICT^fjOi)

The analytic representation i s compared with the experimental data

in fig 1 The analytic representation i s used in order to determine the

rectifying value of 8 hy minimising R bull O-P) p being defined in

eq 22 of ref 1 The appropriate value of 8 is used to determine the

activation energy frequency factor and related kinetic parameters

References

1) V Maxia S Oralis and A Rucci Journal of Luminescence J 378 - 388 (1971)

- 13 -

XS

lt 15

10

I point experimental point raquobulllaquo

350 400 450 500 560 600 650 femp K

Fig 1 Cnonarison of analytic versus experimental flow curve

-10

-15

5 B s ^xxoW Fig 2 Rectified data for peak I of CaF2Hn

- H -

XXmxKT Fiji i Rectified data for peak II of CaF2Hi

0

5 gt c -5

-raquo

-15

1

bull bull bull bull bull bull bull

- bull bull

bullbull bull bull bull bull bull

bull bull

5 IB 17 IB 19 20 2 XXOJxW

Fif 4 Rectified data for peak III of CaF2Mi

- 1 5 -

Fowler

Would the atteapt-to-eseape frequency really be spuriously increased i f the heating rate were so nigh that several true peaks only appeared as one Is this in the right direction Surely Dr Horan said that he obtained s = lo (which i s too high to be reasonable) when his peaks were narrower than expected from simple theory

Adam

I do not think that there is a direct connection between the peak width and

the frequency factor so that one could not say offhand what will be the effect

of widening the peaks on the frequency factor

Mason

In the second slide yon determined E and s from a central portion of the

curve Did you try to determine E and s from the cxtieme parts of the curve

Adaa

Tes we did sone hand calculations but the results were nonsensical

Attix

Did you study natural fluorite or CaF-iMn I believe i t must have been the

fluorite but your t i t l e erroneously specifies CaFgiHn

Adaa

MBIpound gave us the dosimeters saying that the powder within was Caf2lfn If

however Dr Attix says this is their natural fluorite he is probably right

- 16 -

Investigation of

TtTnTrttradeilsclaquollt lithium Borate Classes

using Electron Spin Resonance

by

Douglas ampbull Shearer

Physics Departaont

St Bartholomews Radical College

London

The trapping centres involved in the theraoluminescence of lithium borate glasses have been identified as holes trapped on bridging and non-bridging oxygens in tfca glaa matrix The results of isothermal annealing experiaents indicate that the untrapping process occurs over a continuous spectrum of activation energies The radiation induced 8SR signal froa the glasses with a high alkali content decays fastest except for the anoaalous behaviour of the pure borate glass in which the signal disappears rapidly at room temperature The addition of aanganeae chloride increases the decay rate and reduces the number of trapped teles Manganese occurs in two sites in the glass lattice and their is evidence of this in the thermoluminescent spectrum This spectrum can be altered by the addition of other activators Heavily manganese doped glasses exhibit an additional glow peak at a higher temperature This has been assigned to the transition

Hn + e ^ Mn + hr

which occurs on post irradiation heating

A model has been proposed for the thermoluminescent process in these glasses and some suggestions for the improvement of crystalline lithium borate phosphors have been advanced

Present address Physics Department St Williams Hospital Rochester Kent

- 17 -

There axa aall daflaad probleaa to aolve la tho invntigation of any thaiaalmdashImanaat aubstanoe tha nature and anatier of the trapping and lierlnoananno centraa (anion aay ba aynonyaoua) Bust bo detemlned The kJnetiM leading to the oaiaBlon ara alao isttwrtant Zlntron spin reaonanm la a uaefal tool for laveatigatlBg tfaaaa paranatallaquo In the aaaa of the llthiun Borate group Irradiation Inlnoas a signal ahloh e n ba eoally followed The ouatonr ntivator - divalent bullangenaae - la a paraaagaatla elaaint nhioh giTea a characteristic signal Lithium borate l taalf la atndiad aoat easily orar a aide range of ooaposltlon In tha v i t -reoua atate

PMaauniar

a l l the axperlnantal glaaaea were prepared fraa Analar and Furlaa grade raagaata In a platlnun cro ib lo The firing teaparature aaa 1000degC Mangnnaae and other iasuritlea wars added aa chlorides nitrogen was paaaad through the furnace to ainlniae the quantity of trivalent aanganaaa preaent in the glass All glasses sera aaenohed in eater after 30 aia-ntes in the fornaee

For ESR work the glasses were le f t aa small chunks but for theraoluojlnoanenno atadiea the glass was groand and alaTad to a grain aiae of 80 - 160 aeah 15 aeV aleotrona fran the linear accelerator at St Baiifaoloawwa Hospital ware and for al l tha agpsrlnaatal irradiationa Tha Mcondaiy asiasion monitor deacribed by kotblatv vaa used for the dose callhrationa

Tor a Tslld ooaparlasn of signal helghta f isa different glasses a l l signal heights vara aoml i sed to that of a ruby standard Boosted on tha ooapnaetiag tabe TMa la essential for the range of glasses studied here u dleleotrio I o n la the high alkali oxide glaaaea oan rsdaee signal height by over $0JC The aenaltiTity of tha apeotroaeter vaa aaaaaaad using a known quantity of DPPH la bauana and employing tha standard double inteshygration aethoda auanrised by Poole

ThsraolaaiaeaooBt apsotra vere deterained using the apparatua dee eribad by Harris A Jackson3 anion has a range of 200 - 600 an The appshyaratus desorlbed by Xarsaark at al waa and for a l l quantitative therao-luaiaeaoence Fits to the varioaa kinetics expressions sera done using a IOT-8 ooaputer with a W ferri te core aeaory store

TRArrMJK CHUMS

Ina 13B signals from lrradisted llthlua borate g leans are as bullbona In yig 1 Ths top eight algaals are the original radiation induced spectre The bottom signal i s that mainng after oaraful aonallng

The overlying J and 4 peaked signals havs bean attributed by Grisooa at al to a centre oonaletlag of a hole tiappad on an oxygen bridging between lame and four oo-ordineted borons la the glass structure

The Haailtooian suggested by the above authors for tha structured algnal I s

- 18 -

faring = BCgSH bull g S 2 H 2 bull g SjHj) bull ASI bull A J S J I J bull ASjl 3

with g amp A valnes which wary with eoapoaition

The underlying signal has not baan as thoroughly investigated but i s baliarad by some workers to oe due to holes trapped on non-bridging oxygens

The number of trapped holes i s a function of eoapositiont dose temperatur and raquotorage t iaa The signal i s seen to decay at a l l temshyperatures dona to 77TC - the loaaat investigated I t seems likely that there i s a oontinnous apeotrua of activation energies for the untrapping prooass

Growth curves for the signal are shown in Hits 2 3 The effect of decay i s seen in the difference between tha r i t ive positions of the curves at 7 7 and room temperature

The curves saturate at about 2 x 10 rad when the number of trapped holes i s of the order of 5 x 10 ee after 24 hours s t 77 K Ins number of trapped holes i s independent of pro-irradiation and annealing (See Flit a) This indicates that the traps are not radiation induced

The rate of decay la composition dose and temperature dependent The decay rates of the low alkali oxide glasaes (with tha exception of the pure borate glass) ars least (Pie 5 ) The pure glass deoays rapidly at room temperature The high dose signals decay relatively faster (see Fig 6) Decay curves cannot be fitted by simple 1st or 2nd order expressions However an expression equivalent to that proposed by aedllm for theimo-lominsseent daoay from lerela with a distribution of activation energies gave reasonable f i t s (Pigs 7 8)

T^TwwanwjcE CHTTBES

The usual activator - divalent manganese - gives an E3B signal whieh variea with bass glas- composition and manganese concentration The -iinclaquoTrmdash ion i s more stable in tha lower alkali-oxide glasses (table I )

TABIE I

Intenaityunit sample mass

Intensity manshyganese atom

11

101

1001

12

098001

156002

HJ

097002

231005

14-

1707

5321

15

1501

578035

01

348011

24700

There ara two signals one at g a 2 and the other at g a 4 3 The g bull 2 signals for KT ga mole are shown In Pilaquo 9 Tha change in the g bull 2

- 19 -

aigaal for iaenaaiag aanganeae oancantxation la ahorn in f i n 10 Ina loaa la raaolution af tb hyperfiao atructure at higher eoneentrationa ia dna to dipolar broadening Iha g bull 43 aigaala ara aboan in gtilaquo 11 bdquo A Haalltnnlan for tte g laquo 2 aignal haa baan pmpoaad by Bleaney Snbina i o

^bull-B8JJsect+D[sI2-JS(S1)]AJS-08HJ for S- l - |

a Kadaie et a l baja giaan a HaaUtonian for tha g gt 43 signal produced by iaoalaetnniSfa in lithlua ailioata glaaaea Thia haa been appliad by Lunter et a l to aanganeae in aoaa glassy aatrieea i e

(^f-eBH-S + AVs1 for l - f s -J g-4-3 A- S

These aigaala hare bean attributed to aanganeae in tao different aites in the glass l a t t i ce The doainant g raquo 2 signal oorresponda to aanganase in an axially ajaantile alta The aigoal at g = 43 i s aaaosiated with rhonbio ayaaatry The tao aites concerned oan be tentatively identified aa aanshyganeae in netwoik aodifying and network foraing poaitiona

Carina oopper and iron have also been added aa obloridea The only ESR aignal raquoas aaen at g s 43 froa iron Thia haa been attributed toferric iron in aa orthorhoabio eleotroatatic crystal field (Caatner et

MB tTTECT Cf BAPIATigi CH THE ESB SIMM HOT DOFSB 6IASSTS

I t ia found in these glaaaea that the nuaber of trapped holes after irradiation i s l e ss than in the undoped glasses - the greatest decrease being Man in the glasses with tha suet added iapurity (Pine 12 H i

12 Theas results are ooapatible with those obtained by eriaeon et al which ahoa that halogen Vk oentea ooapote for liberated holes with the boron oxygen centrea thua raduajtng the oharactaristio alkali borate radiation indooed signal The rata of decay of tha aigaal ia also increased in the doped glaaaea (Flu 14) Thia will also decrease the effective nuaber of trapped holea

THMifllfflllaiBBfflWT SPBCTBA bull

Tharaolnminaaeont apaotra have bean obtained froa pure and doped glassee The nonaotiTated glass spectra are siailar to those of the nore lightly aanganeae doped glaaaea Thia iarliee that lualnesoeaoe in undoped glaeaea ia due to traoea of aaaganeaa These spectra peak at approziaately 620 an The spectra were aubatantially the sane for tha two hole traps which ladieates that the lnainosoonoo oentre la the sens ia both cases Within tha l i a l ta of tha experlaant no dependence of tht apaottua on dose w observed The tbtraolualneaoent apaotrua aoved towarda longer wavs-langtbe tin greater the oonoentration of aanganeae Aring aubaldlary feature la tha apeotruB of tha pure lithloa borate glassea waa a aaall peak at about 47$ an ( f lu 1Sgt which waa aore obrlotlaquo In tha lower alkali oxide glasses la addition the pore 01 glesa aotivated with 10 ga nole aanganeae showed

a peak at 5J0 an In the 15 glass doped with 1 0 ^ ga BO another aaall peek ma observed at 220 mu Thia caa only visible on to lag aeala ( H g l l f i ) Theaa apeetra a n raquolightly twperature dependent -the emission shifting towards the shorter wevalengtha on inorease of tea-perature (Table I I )

TABLB II

^ ^ S l a a a Temp Coapositien Bang

Peak(au) 77degK^Eooa leap

With (an)

Peek(att) Eooa Temp- 200 C

Width(au)

bdquo Fek(mu) 200 C-raquo laquo raquo C

fidth(mu)

11 lO

615plusmn15

550-710

610+10

5VO-700

61010

535-700

12 10-

620+10

560-700

615+10

560-690

63020

$20-690

13 10

640+10

570-710

6305

570-695

14104

6W+10

535-720

6305

575-710

625+5

570-700

15 10

61010 (5 tr -70O ( Peaks (A B C 6gtraquolaquo0-C70

615 10

555-710

610 5

55-695

01 10 -

6105 ( 5 0 laquo 7 5 ( Feaka ( A B (530~laquo5

610 5

560-675

610 5

560-680

J3 10 4 It baa keen shown (Blnghsa Parka tanter at al ) that the aaiasion peaking at -620 an ia aasoaiatad with nangsneae in ootahadral coshyordination alille manganese In tetrahedrally sjenil i lo surroundings gires rige to a green emission (approximately 530 an) I t has alao been noted (tajl 7 that the orange emission ia omenohed at higher teaperatores while the green ia relatively unaffected Thia amy explain the temperature effect aeon in the apaetxwa of swat glasses

the predominant emission at about 620 an and the 530 an amission hat been explained (Kedlin1 Bingbam 4 Parka1 ) as due to the K^ (T J laquo Ss (A1J tranaitlon - the differenoe ia wavelength being dna to the ayueetry change There ia a probability of the 4 (T ) - 6pound (AJ

transition abieh oould gire rime to the obserred emission at about 450 an -the higher lerels giring rise to the shorter warelength emissions

(Fin 17V (Curiatrade)

Whan doped with oeriua and upper the spaotrua ia altered aa shown The blue luminescence for oeriua at 385 au ha been attributed

to a transition between the doublet levels

S ^ ^ 1 7 Konoslent oopper i s reported (Xarapetyaa1) to give an emlaaion about 500 an and the sbsense of any 18H apootma n infonea this olusion The sopper apeutium ia extremely tmdashporalius dependant

at

- 21 -

Bassilaquo The tiieraoluainBscent eaiasion oan be examined aa a function of

SSJt signal height by step annealing individual glass saaplaa The resultant plot la not completely linear in a l l oases This i s not surshyprising in view of the tao contributory traps and the spectral shift with temperature Plots for two glasses are shown in Fine 18 19 The relationship i s significant enough however to assign the glow peak in these glasses to the hole traps observed by ESR

The glow curves are shown in f i g 20 Data are given in Table III

TABIB III

bullmdash__Jgtoae Composition mdashmdashmdash^

deg2 B2 deg3

L 02 BjOjIO- ga Vole lb

10 - 3 bull

102

101

107rada

190 + 8

200 + 8

141 8

Low tamp High temp 150 + 8 278 + 8

Low temp High lamp 138 + 8 265 + 8

106rado

168 + 8

163 + 8

1 laquo + 8

lO^rada

168 + 8

155 + 8

155 + 8

138 + 8

lO^radt

150 + 8

150 + 8

157 + 8

I t can be seen that increasing manganeae concentration gives riae to a higher temperature glow peak After irradiation these glasses have a purple t int due to Kn Tola disappears at the higher glow peak tempershyature The peak may therefore be correlated with the transition

e + Hh - gt bullraquo + hv

The actual glow peak temperaturaa are dependent on composition dose time and temperature of storage

Tiieraolumlneseent response eorvea are ahown in Elg 21 These are for undoped glasses The low responses for the BjO and UJOBJO glasses are due mainly to the laek of trapped holes With the addition of 10 ga bullale manganese la each glass the results are aa shown in Fig 22 These results oan partially be explained by better activator efficiency and trap stability in the low alkali oxide glasses The response curves for the _ manganeae activated 12 glasses are shown in Tie 23 The peak for the 10 ga mole activate glass sen be explained as the beet compromise between number of effective activator atoms and number of trapped holes The resshyponse curves due to the other aotivators am as shown (Jja_2a) The

- 22 -

increased responses due to oopper and oeriun are primarily due to tho change In emission speotra That tho above considerations ara not tho whole story la shows by Fin 25 l raquo tho number of observable trapped holes and luminshyescent centres do not entirely determins tho thermoluminescent outputlaquo Con-oantration onenohing meohsnisms are almost oertslnly involved in tho more heavily doped glaases and difforaneoa in energy tranafar propertiea of the base glosses may be important

MODEL FOB THgarcmimiBscmcK

Ihe above experimental data lead to a Model with at least tao hole traps These trapa hare a distribution of aotiTation energies The traps are not dependent on radiation formation added impurities provide additional trapping oentraa The lnadneaeent centre i s independent of the trap and the Mission spectrum can be altered by changing actiTators So far i t haa not been possible to determine whether eleetrona or holes are entrapped but a simple model assuming electron unt rapping i s shown in Pilaquo 26

The high tempersture peak in the heavily manganese doped samples can be pictured aa a result of the prooees shown in Fig 27

COHCUBICBS

From the sbcTe data it would aeea that the most efficient manganese activated phosphors are those in which the alkali oxide content i s ss low ss possible and which are prepared under reducing conditions As halogens appear to be responsible for decreasing the number of useful trapped holes the manganese should not be Introduced as the chloride Manganese acetate would serve Urn purpose of eliminating the competitive traps I t would also help to reduce the manganese to the divalent state

Preliminary preparations of crystalline lithium borate phosphors have been carried out along these l ines with good results

An sltemative method of increasing the effeetive effioienoy i s to shift the emission spectrum This can be achieved by doping with activators giving emission spectra in the shorter wavelength region

As the ISR signals from orystals appear substantially the same work i s being carried out to extend these ideas to the range of eryatalline phosphors

- 23 -

REFERENCES

J Rotblat Natura (London) 175 745 (1955)

CP Poo llaquo Electron Spin Reaonance ( i n t e r a e i e n c e ) (1967)

AB Harris 4 JH Jackson CEGB Report RDB1I111 (1968)

CS Karimark J I h i t a and J F Fowler Phys Med B i o l 2 273 0964)

P Beekenkanp P h i l i p s Reaaarch Report Supplements No 4 (1966)

DL Grieeoa PS Taylor PF Ware A PJ Bray

J Chelaquo Phys 48 5158 (1968)

WL Medlin Phys Rer laquo3_ 502(1961)

B Bleaney A RS Rutine Proo Phya Soc JJ 103 (1961)

RW Kediie DH Lyona A Kestigian K Phys Rer 138 A(918) (19B)

SG Lunter C O Karapetyan NB Bokin A DM Yudin Soriet loyales - Solid State 9 2259 (1968)

T Ceatner G Newell N Holton A C Sliohter J Chelaquo Phys 2 668 (I960)

DL Griaeoa PS Taylor A PJ Bray J Chan Phya 50

977 (1969)

K Binghaa A S Parka Phyaiea A Cham of Glass 6 224 (1965)

WA Weyl Coloured Glasses (The Society of Class Technology)

(1951)

I L Medlin J Opt Soo Aner pound J 1276 ( 1965 )

D Curia Traquollaquo1neioenoa in Crysta l s llethuan A Co Ltd (1965) 0 0 Karapetyan IZT AKAD NAUK SSSR SER FIZ 2g 539 (1961)

- 2 4 -

RADIATION-INDUCED ESR SPECTRA OF LITHIUM BORATE GLASSES

i-tn MBi 2-WC 9

Fig 1

DOSE RES PONSE CURVES OF PURE LITHI UM BORATE GLASSES AT 77deg K

10 bull

sect W in bullI Vgt ui

i 3

Kgtl bull i i i W W raquo W TO

DOSE (RADS)

Fig 2

- 2 5 -

gw

DOSE RESPONSE CURVES Of PUK LITHIUM raquoCRA1E GUSSES

AT ROOM TEMPERATURE

bull 1 1

bull 1 = 2

3 - g i ^ ^

J ftr-

Fig 3

O Vira in FvwiMabJnatfiMi

i ^ S D

reg lslaquoUlaquo

4r

t

raquoraquo raquo 3 i OMflraM

raquo g

Isl IKRIVATIVE E S R SIGNAL HEIGHT

N0RMMISE0TO INITIAL HEIGHT

I l 4 DERIVATIVE E S R SIGNAL HEIGHT NORMALISED

TO INITIAL HEIGHT 9

I

I

- 2 7 -

CUttS M i raquobullbull

mon ranwruK KCAV OF cwrositwlaquo u t ^ ras n a i euss M S - raquo I gMOS t - a bull bull L I

nlaquo 6

- 2 6 -

UDft |01 la4RHgtMliHll _

si s- M

V R J O J IB gm bull Mn

T

|0raquo|0) bull bull - - bull bull bull bull bull -

n 9-

ESB WBWtKAT bull - FOD UIOLAW WHH raquo K B E N T FKOKRtTMM

M t c - m mdash raquo iju=o-raquo

^ A bull s

-

x ltraquoVn 1- HMlaquo Hu UfO raquo(DfUT1 ftlaquolaquo

ris lo

- 2 9 -

E8R S n i U k U A T f - 4 FC li 1 GLASS ACTIYATEDWITH DIFFERENT

- 3 0 -

ENfCr O ADOID WMKaringaringtM ON L M DQSf bull

laquornooM Jtmmmm

i

I I 1 sect 3 i

I t

l

i r B

I

ltt

rf laquo f

raquo

- tf

i f

i i 1 1 raquo raquo raquo

Fig 12

- J l -

IKICT V raquo i l v WEMHT ADHB ACTIVATOII ON I U OOU HMftWS OF I I CUtSSAT ROOM TWHUTUM

51 i 1

I K

Ml (raquobullraquogt

Pig 13

DECAY RATES Of IRRADIATED MANGANESE ACTIVATED 14 GLASS AT ROOM TEMPERATURE

1 Tzzia

k 2 I

KgtgmimhraquoMn

^

raquo-raquo

I Hi

MimrtH at M M tamp

f i 14

32

- 3 3 -

DOm WITH raquo - laquo raquo bull HOUt HAMCAHUI

bull jplusmnplusmnjraquojioiiiplusmn plusmn

ti- 16

- 3 4 -

Pig 17

PLOT OF LIGHT IN GLASS AS A FUNCTION OF 1st DERIVATIVE E S R SIGNAL HEIGHT

FOR M COMPOSITION

bullbullORONHTPERFINEFEAK

bullASYMMETRIC FEAK

bull bull I -J O gt 4 0 K 100

OF 1st DERIVATIVE E S R SIGNAL HEIGHT

Pig 18

- 3 5 -

n a OF LIGHT IN MASS AS A FUNCTION OF

MDOIIVATIVELSIL SIGNAIHEICHTFClaquo 15COMPOSITION

bull bullOMNHVFFJFIHEFEAr

bull ASVMCntlC PEAK

r

raquoCf lUOfHIVAI IVELS i l SIGNU WIGHT

Mg 19

CLOW CURVES FOR IRRADIATED III LITHIUM BORATE

Tig 20

December 1971 RisS Report No 249 Part I (pp 1 -443)

Proceedings of the

Third International Conference on Luminescence Dosimetry

Held at

The Danish Atomic Energy Commission Research Establishment RisO

October 11 -14 1971

Sponsored by

The Danish Atomic Energy Commission

and

International Atomic Energy Agency

Editor

V Mejdahl

Abstract

Seventy-eight papers a r e presented from the 3rd International Conshy

ference on Luminescence Dosimetry The papers a r e arranged according

to the following topics Mechanisms of Thermoluminescence (TL) TL Inshy

strumentation Improved TL Materials Propert ies of TL Materials Thershy

mally Stimulated Exoelectron Emission Radiophotoluminescence TL in

Clinical and Personnel Dosimetry Dating and Background Radiation Monishy

toring Charged Part ic le Neutron and UVdeg Response Miscellaneous Propshy

ert ies Effects and Applications

ISBN 87 550 0120 3

ISBN 87 550 0121 1

FOREWORD

This publication presents the papers given at the third International Conference on Luminescence Dosimetry The papers reflect the extensive research and development that have been accomplished since the second International Conference on Luminescence Dosimetry held at Gatlinburg Tennessee in 1968 The great number of papers seventy-eight clearly Indicates the continuing interest in this field There were 144 registered attendees representing twenty-seven countries and three international orshyganizations Austria Belgium Brazil Bulgaria Canada Czechoslovakia Denmark Finland France Germany (DDR and the Federal Republic) Greece Hungary India Israel Italy Japan Mexico The Netherlands Norway Poland Portugal Sweden Switzerland United Kingdom U S A Yugoslavia CERN IAEA and WHO

In connection with the conference a commercial exhibition was arranged which snowed the latest developments of measuring equipment Eight comshypanies representing six countries participated in the exhibition

To enable rapid publication the papers have been reproduced directly from the manuscripts handed over by the authors A few papers were withshydrawn by the authors and in such cases only abstracts are given Discusshysion on a paper i s inserted at the end of the paper The publication i s in three parts Part I contains sessions I-V part H sessions VI-IX and part m sessions X-XU The grouping of papers into sessions appears from the l ist of contents which i s included in each volume

The assistance of Miss L Kristiansen Miss B Ramgill and the printing office staff in the publication of the proceedings i s gratefully acshyknowledged by the Arrangements Committee

V Mejdahl

CONFERENCE OFFICERS

Co-Chairmep

J F Fowler

Research Unit in Radiobiology Mount Vernon Hospital Northwood United Kingdom

A Scharmann University of Giessen Federal Republic of Germany

Programme Committee

K Becker Chairman

Oak Ridge National Laboratory U S A

FH Attlx

U S Naval Research Laboratory U S A

J R Cameron

University of Wisconsin U S A

J H Schulman Special Advisor U S Naval Research Laboratory U S A

Local Arrangements and Publications Committee

V Mejdahl Chairman Danish AEC RisB Denmark

CA Carlsson Vice-Chairman University of Linkfiping Sweden

L Boslashtter-Jensen Danish AEC RisO Denmark

E Pedersen

Danish AEC RisB Denmark

CONTENTS

PARTI

Page

MECHANISM OF THERMOLUMINESCENCE I Chairman S Watanabe University of Sao Paulo Brazil

Interpretation of Resolved Glow Curve Shapes in LiF (TLD-100)

from 100deg to 500degK EB Podgorsak PR MoranandJR Cameron 1

Analysis of Thermoluminescence Kinetics of CaFbdquo Mn Dosimeters

G Adam and J Katriel 9

Investigation of Thermoluminescent Lithium Borate Glasses using Electron Spin Resonance Douglas R Shearer IS

A Simple Thermoluminescence Model and its Application in Thermoluminescent Dosimetry R Abedin-Zadeh 41

Efficiency Variations of Thermoluminescent LiF Caused by Radiation and Thermal Treatments Per Spanne and C A

Carlsson 48

MECHANISMS OF TL II Chairman A Moreno y Moreno Inst of Physics Univ of Mexico Mexico

Continuous Model for TL Traps Shigueo Watanabe and Spero Penha Morato 58

The Influence of Hydroxide Impurities on Thermoluminescence in Lithium Fluroide L A DeWerd and T G Stoebe 78

Influence of OH Anion on the Thermolumiscence Yields of Some

Phosphors Toshiyuki Nakajima 90

Abnormal Thermoluminescence Fading Characteristics A G Wintte MJ Aitken and J Huxtable 105

Fading In Thermoluminescent Dosimetry Zdenek Spurny and Josef Novotny 132

Page

Effects of Deep Traps on Supralinearity Sensitisation and Optical Thermohuninescence in LiF TLD C M Sunta V N

Bapat and S P Kathuria 146

Supralinearity and Sensitization V K Jain and J B Sasane 156

Re-estimation of Dose in LiF G S Linsley and EW Mason 1 ST

Properties of Some Deep Traps in Lithium Fluoride- E W Mason and G S Linsley - 164

TL INSTRUMENTATION

Chairman T Higashimura Research Reactor Institute

Kyoto University Osaka Japan

Possible Elimination of the Annealing Cycle for Thermoshy

luminescent LiF G A M Webb and H P Phykitt 185

Significant Changes in TLD Readings Produced by AC Heater

Currents J E Saunders 209

Photon Counting as Applied to Thermolumiaescence Dosimetry

T Schlesinger A Avni Y FeigeandSS Friedland 226

Dosimeter and Reader by Hot Air Jet H Oonishi O Yamamoto T Yamashita and S Hasegawa 237

The Emission Spectra of Various Thermoluminescence Phosphors K Konschak R Pulzer and K HQbner 249

IMPROVED TL MATERIALS I

Chairman Z Spumy Nuclear Research Institute Prague Czechoslovakia

Some Thermoluminescent Properties of Quartz and its Potential

as an Accident Radiation Dosimeter D J McDougall 255

Thermoluminescent Enamels M Mihailovic and V Kosi 277

Thermoluminescent Phosphors based on Beryllium Oxide Y Yasuno and T Yamashita 290

A Study of Silver Iron Cobalt and Molybdenum as Lithium Borate Activators for its use in Thermoluminescent Dosimetry

A Moreno y Moreno C Archundia and L Salsberg 305

Page

IMPROVED TL MATERIALS II Chairman T Schlesinger Soreq Nuclear Research Centre

Yavno Israel

Sintered TL Dosimeters T Niewiadomski M Jasinska

and E Ryba 332

Studies of the Thermoluminescence of Lithium Fluoride Doped

With Various Activators M E A Robertson and W B Gilboy 350

A New TL LiF (NTL-50) Which is Unnecessary of Annealing

its Properties Especially for Application and the Results of Several Practical Cases Katsumi Naba 357

Thermoluminescent Response of Natural Brazilian Fluorite to 137

Cs Gamma-Rays S Watanabe and E Okuno 380 Thermoluminescence of Natural CaF~ and its Applications

C M Sunta 392

Improvement of Sensitivity and Linearity of Radiothermolu-minescent Lithium Fluoride G Portal F Berman Ph Blanchard and R Prigent 410

Further Studies on the Dosimetric Use of BeO as a Thermoshyluminescent Material G Scarpa G Benincasa and L Ceravolo 427

PART II

PROPERTIES OF TL MATERIALS Chairman C Carlsson Univ of LinkSping Linkfiping Sweden

Dose Relationship Energy Response and Rate Dependence of

LiF-100 LiF-7 and CaS04-Mn from 8 KeV to 30 MeV G Eggermont R Jacobs A Janssens O Segaert and

G Thielens 444

On the Non-Linearity and LET Effects of the Thermolushyminescence Response Toshiyuki Nakajima 461

On the Sensitivity Factor Mechanism of Some Thermolushyminescence Phosphors Toshiyuki Nakajima 466

The TSEE Response of Ceramic BeO covered with Different Absorbers During Gamma and X-Ray Irradiation E Rotondi and T Suppa 480

Low Temperature Monitoring Using Thermoluminescent Materials Robert D Jarrett J Halliday and J Tocci 490

Dependence of the Response of LiF TLD 100 Powder

Incorporated in Silicone Rubber on Grain Size P Bassi G Busuoli A Cavallini L Lembo and O Rimondi 504

Manufacture of Uniform Extremely Thin Thermoluminescence Dosimeters by a Liquid Moulding Technique Geoffrey A M

Webb and George Bodin 518 7

The Consistency of the Dosimetric Properties of LiF in Teflon

Discs over Repeated Cycles of Use T O Marshall K B Shaw and E W Mason 530

Influence of Size of CaFraquoMn Thermoluminescence Dosimeters 60 on Co Gamma-Ray Dosimetry in Extended Media

Margarete Ehrlich 550

THERMALLY STIMULATED EXOELECTRON EMISSION Chairman P Maushart Berthold-Frieseke Vertriebsgesellschaft GmbH Karlsruhe Germany

Exoelectronic Properties of AlgO-Solids G Holzapfel

and E CrysBou 561

Chemically Thermally and Radiation-Induced Changes in the

TSEE Characteristics of Ceramic BeO R B Gammage K Becker K W Crase and A Moreno y Moreno 573

Exoelectron Dosimetry with Oxide Mixtures M Euler

W Kriegseis and A Scharmann 589

Low-Z Activated Beryllium Oxide as a High Sensitive Radiation Detector in TSEE Dosimetry D F Regulla G Drexler and L Boros 601

TSEE Dosimetry Studies T Niewiadomsld 612

The Optical Stimulation of Exoelectron Emission J Kramer 622

Page

Characteristics of Selected Phosphors for Stimulated Exoelectron Emission Dosimetry P L Ziemer W C McArthur V L McManaman and G D Smith 632

Problems in the Use of Proportional Counters for TSEE Measshyurements L D Brown 654

Trapping Centers in CaF2Mn from Thermoluminescence and Thermally Stimulated Exoelectron Emission Measurements on Undoped and Mn Doped CaF Samples K J Puite and J Arends 680

RADIOPHOTOLUMINESCENCE

Chairman K Becker Oak Ridge National Lab

Oak Ridge USA

Formation Kinetics of Color Centers in RPL Glass Dosimeters

AM Chapuis M Chartier and H Francois 692

A RPL Dosimetry System with Fully Automated Data Evaluation M Dade A Hoegl and R Maushart 693

New Type of High-Sensitive and Soil-Insensitive RPL Glass Dosimetry R Yokota Y Muto Y Koshiro and H Sugawara 709

Laser Pulse Excitation of Radiation Induced Photoluminescence

in Silver-Activated Phosphate Glasses F Hillenkamp and D F Regulla 718

The Response of Radiophotoluminescent Glass to Co Y-and 10-30 MeV Electron Radiation L Westerholm and G Hettinger 727

Some Ways of Applying the Capabilities of Various Luminescence Methods in Personnel Monitoring M Toivonen 742

Radiation-Induced Optical Absorption and Photoluminescence of

LiF Powder for High-Level Dosimetry EW Claffy SG

Gorblcs and F H Attix 756

Page

TL IN CLINICAL AND PERSONNEL DOSIMETRY Chairman F H Attix U S Naval Res Lab Washington DC USA

Two Years Experience of Clinical Thermoluminescence Dosimetry at the Radiumhemmet Stockholm Bengt-Inge Ruden 781

Thermoluminescence Dosimetry for Clinical Use in Radiation Therapy D S Gooden and T J Brickner 793

TLD - Calcium-Fluoride in Neutron Dosimetry TLD -Calcium-Sulphate in Health Protection Service D K Bewley and pound Blum 815

Lithium Fluoride Dosimeters in Clinical Radiation Dose Measureshy

ments N Suntharalingam and Carl M Mansfield 816

A Personal Dosimeter System Based on Lithium Fluoride Thermoluminescent Dosimeters (TLD) A R Jones 831

Progress Towards Automatic TLD Processing for Large-Scale

Routine Monitoring at RisB Lars Boslashtter-Jensen and Poul Christensen 851

UV Induced Thermoluminescence in Natural Calcium Fluoride

Emico Okuno and Shigueo Watanabe 864

A Current Look at TLD in Personnel Monitoring F H Attix 879

PART m

DATING AND BACKGROUND RADIATION MONITORING Chairman M Aitken University of Oxford Oxford England

New Techniques of Thermoluminescent Dating of Ancient Pottery

I The Substraction Method S J Fleming and D Stoneham 880

New Techniques of Thermoluminescent Dating of Ancient Pottery

II The Predose Method S J Fleming 895

Progress in TL Dating at RisS Vagn Mejdahl 930

Some Uncertainties in Thermoluminescence Dating Mark C Han and Elizabeth K Ralph 948

Environmental and Personnel Dosimetry in Tropical Countries Klaus Becker Rosa Hong-Wei Lu and Pao-Shang Weng 960

Natural Radiation Background Dose Measurements With CaF2Dy TLD D E Jones C L Lindeken and R E McMillen 985

Impurities and Thermoluminescence in Lithium Fluoride MJ Rossiter DB Rees-Evans and S C Ellis 1002

CHARGED PARTICLE NEUTRON AND UV RESPONSE Chairman N Suntharalingam Thomas Jefferson University Hospital Philadelphia Pennsylvania USA

The Measurement of Dose from a Plane Alpha Source J R Harvey and S Towns end 1 015

Thermoluminescent Research of Protons and Alpha-Particles

with LiF (TLD - 700) B JShnert 1031

Thermal Neutron Dosimetry by Phosphor Activation

M R Mayhugb S Watanabe and R Muccillo 1040

Determination of the Sensitivity of the CaF2Mn Thermoshyluminescent Dosimeter to Neutrons M Prokic 1051

Triplet Exciton Annihilation Fluorescence Changes Induced by

Fast Neutron Radiation Damage in Anthracene D Pearson P R Moran and J R Cameron 1063

Mixed Neutron-Gamma Dosimetry S K Dua R Boulenger

L Ghoos and E Mertens 1074

Energy Response of Certain Thermoluminescent DosimeterB

and Their Application to the Dose Measurements H K Pen-durkar R Boulenger L Ghoos W Nicasi and E Mertens 1089

Tm-and Dy-Activated CaSO Phosphors for UV Dosimetry

K S V Nambi and T Higashimura 1107

Transferred Thermoluminescence in CaF~nat as - Dosimeter of Biomedically Interesting UltravioletRadiation Edwin C McCullough Gary D Fullerton and John R Cameron 1118

Page

MISCELLANEOUS PROPERTIES EFFECTS AMD APPUCATIONS Chairman H Francois C E A Paris France

Storage Stability of TL and TSEE from Six Dosimetry Phosphors AE Nash VH Ritz andFH Attix 1122

Optical Absorption and ESR Properties of Thermoluminescent Natural CaF2 after Heavy Gamma Irradiation Ks SV Nambi and T Higashimura 1155

Methodological Aspects on Measurements of Steep Dose Gradients

at Interfaces Between two Different Media by Means of Thermoshy

luminescent LiF Gudrun Aim Carlsson and Carl A Carlsson 1163

Kapis as a Thermoluminescent Dosimeter N T Bustamante

R Petel and Z M Bartolome 11 77

Experimental Modification of Thermoluminescence by Static and Explosive Deformation D J McDougall 11 93

Some Dosimetric Properties of Sintered Activated CaFlaquo

Dosimeters D Uran M Knezevic D Susnik and D Kolar 1195

Panel Discussion 1209

Author List 1217

List of Participants 1220

List of Exhibitors 1229

1 -

Interpretation of Resolved Glow Curve Shapes in

LiF(TLD-100) fron 100deg to 500degK

by

E B Podgorsak P R Horan and J R Caaeran

Laboratory of Medical Physics

Physics Department and Radiology Department

University of Wisconsin Madison Wis

Abstract

We note that each glow peak of LiF(TLD-100) in the temperature range

from 100deg to 500degK displays a shape peaking temperature dependence on

heating rate and lack of peaking temperature dependence laxm total light

output whidi are in detail as predicted by the most simple thermally

activated kinetics in the f irst order Randall-Wilkins limit We also

note however that the glow curve breadth is anomalously large at low

temperatures and anomalously small at high temperatures While physically

reasonable although improbable mechanisms might explain the larger

breadths there seem to exist no physically reasonable direct mechanisms to

explain the narrower breadths We propose an indirect explanation in which

the activation energy i s i t s e l f slightly temperature dependent We discuss

how this effect explains the observed results and speculate on other

implications

2 -

Introduction

Since cur abstract was submitted a detailed description of our experi-aents relating to correlations in glow peak behavior from 100 to S00K has been published1 We therefore wish to discuss here primarily an intershypretation of resolvable glow curve shapes and apply these results to the TLD-100 observations Figure 1 shows the ten glow peaks we have studied glow peaks (-1) and (-4) are not optically repqpulated with uv irradiation and this allows us to resolve die details of peaks (u) and (-3) These glow curve shapes each exhibit a 501 half-breadth asymmetry on the law temperature side and at a given heating rate neither the peaking tempershyature Tn nor temperature breadth A depend upon the peak TL intensity This behavior characterizes first order kinetics and consequently we discuss here only the Randall-Nilkins description although our results can also easily be applied to die Garlick-Gibson limit A particularly intershyesting feature is that all glow peaks in this temperature range ham essentially die same temperature breadth 4 = 20 2degC

Glow Curve Behavior

It is not appropriate to pursue all mathematical details here but a brief review of die first order kinetics of thermally activated mechanisms is useful The concentration of trapped charge carriers n corresponding to a single resolved glow peak obeys die relation

raquof-Kn (1)

where w is an activated rate function

laquo bull se-W (2)

and die TL intensity in the simplest case is some fraction of die release rate

I(t) = -cSjn (3)

The above equations can easily be integrated formally one can obtain from diem an implicit expression for die peak temperature

(Eky bull logCEky log is^Ty 1 (4)

When die glow curve is narrow AlaquoT i t is not difficult to show diat

(Ekyraquol (S)

and Eq 4 can be validly approximated as

(Ery - logis^Ty 1 (6)

Me shall return to die expression in Eq 6 later

For narrow glow curves one can also show that analytic expressions can validly be used to approximate die integration of Bqs (1) - (3) The result is

I(laquoT) - bdquo expl bull (6Ty (Eky -exp[(STy (Eky] (7)

- 3 -

where 4T i s the departure from Ta

laquoT = T-Tbdquo (8)

Figure 2 shows the predictions of Eq 7 compared to the experimental glow curve for peak (-3) peak (-3) i s chosen because i t i s the fractionally broadest glen peak and therefore tests our approximations most severely Me note die characteristic tSOt low temperature asymmetry and that the nuaerical result for the glow peak breadth at half-aaxiaua i s

A = ( 2 4 4 ) 0 ^ ^ ) TB (9)

One can now use Eqs (9) and (6) together with die experimentally observed TB and amp to determine E and s There are of course other methods as well but they give similar results and Eqs (9) and (6) most directly illustrate die effects we wish to point out

If we examine glow peak (-1) which has TB 267degK at our heating rate of 35degKmin we find

E(-l) = 76 eV (10a) s ( - l ) = S x 1012 sec1 (10b)

This value for s is to be expected i f die trapped carrier interacts as strongly with neighboring ions in die solid as die ions do with one another die s is die limiting attempt frequency and must be approximately equal to the typical DeBye lattice vibration frequencies These frequencies are indeed about 5 x 1012 s ec 1 for LiF If on the other hand we examine glow peak (-3) we find

E(-3) - 028 eV (11a) s(-3) 107 sec1 (lib)

12 -1 Expressed another way i f we assumed s(-3) = 10 sec tiwn die breadth of peak (-3) is about a factor of two broader than predicted Many explanations have been put forward to explain such anomalously large breadth of glow peaks For example fliere might exist a spread in actishyvation energies E or die trapped carrier might somehow be effectively insulated from die lattice vibrations or there might be overwhelming retrapping effects to effectively reduce die net attempt rate

Finally let i s examine glow peak (5) which has been extensively studied because of i t s use as die primary dosimetry glow peak Here we find not an anomalously large breaddi but an anomalously narrow breadth While i t i s not difficult to give plausible mechanisms to broaden a l ine i t i s very difficult to propose narrowing mechanisms The parameters determined are

E(S) - 22 eV (12a) s(5) laquo 1023 sec1 (12b)

Similar results are also obtained by measuring die logarithmic change of Ta as 3tT i s varied widi an analysis according to Eq 4

The point we wish to emphasize i s that while reasonable although

- 4 -

peihaps unlikely explanations can be Bade for s raquo 10 in glow peak (-3) there exists no simple physically reasonable mechanism for an actual s - 1 0 in peak (S) because this i s a factor of at least 10l larger than the limiting lattice interaction frequencies in the solid

He have found that we can resolve these difficulties siaply by assuming that die activation energy E i s very slightly temperature dependent ke will not present die detailed mathematics here but the following results are obtained

1 Mien an observed glow peak i s narrow 6laquoT_ then a simple analytic approximation i s always valid in integrating the kinetic equations Eos ( l ) - (3) this includes the possibility of a temperature dependent activation energy The most important relation i s

w(T)dt = wp T)1 [ariogw]1 C13) o

2 The resulting glow curve descriptions have exactly the same form as Eqs (4) through (9) except that E and s are replaced by the parameters E and s where

E - ftSOslashECBUlftg (B - 1kT) (14a)

s - expCtE-ECyikys (14b)

3 In Eq 6 the difference between E and E(T) i s exactly balanced by the difference between s and s 4Thus Eg 6 remains valid independent of whether one uses E and s or E and s

4 For glow peak (5) a slight increase in E with temperature amounting to a fractional effect of less than 10~3 (K1) easily accounts for the anomalously narrow breadth and gives a n s = 1 0 resulting from an actual interaction rate of s - 1012

5 Ml other aspects of shape breadth peak height behavior etc are preserved according to the basic Randall-Wilkins results

As a final speculation we propose that other slight temperature deshypendences account for a l l anomalous breadths For example one need not invoke the somewhat unlikely existence of dominating raquotrapping terms to explain the large breadth of peak (-3) since only a small temperature dependence of E provides the same resulting behavior

He can also speculate further on die E vs E behavior l e t us suppose as a very crude model that a l l glow peak traps are roughly the same character for example basically a weak coulomb-like binding stabilized by the surroinding ions As die temperature increases from 0K die lattice undergoes tfiermal expansion He might expect diat die trap depth wi l l f irst increase due to die reduction of die neighboring ion repulsive potentials and with continuing temperature increase die binding wil l eventually begin to decrease due to reduction of the Coulomb attraction Thus die fractional temperature dependence of E for each glow peak would show leading term of the form

- 5 -

E - E A ( l a T - BT2) CIS)

which can be rewritten

E bull Eo(l - b f f - y 2 ) (16)

We think i t i s interesting that by choosing b bull 10 (K) and T - 300K we can f i t a l l the observed clow curve shapes while retaining a single activation frequency s - 1012 sec1 characteristic of lattice vibration interactions and negligible retrapping

References

(1) E B Podgorsak P R Hsran and J R Csjeron JAP 42 2761 (1971)

(2) P R Koran E B Podgorsak USAEC Report COO-1105-164 August 1971

IMs wort wis supported by the United States tonic Energy Agency and by the (ltS nir Force Office of Scientific Research

- 6 -

I I I i i mdash I mdash I 1 1 r i

Eacute 8 8 8 8 8 5 8 8 2 ni) aiuwraquo iron

Tmdashimdashimdashimdashimdashimdashr

SO -40 -30 -20 -10 0 ST-(T-Tmax) [degk]

Figure 2 Glow peak (-3) of LiF(TLD-100) The dotted curve is calculated from Eq 7 and the undotted line is the experimentally measured glow curve

Fowler

Tour explanation of a too narrow peak in terms of a dependence of activation

energy on temperature is Interesting How did you come to this conclusion

What physical processes could lead to such a dependence and are the orders

of magnit ie involved reasonable

Moran

First we looked for a single explanation which could give low-temperature peaks a too large breadth and high temperature peaks a too small breadth At least for low Irradiation levels in l iF (TLD-Ioo) a reasonable single explanation wlaquolaquo~ E = E(T) A possible physical process i s suggested in the written version of thiB paper we suggest that thermal latt ice expansion can give a fractional variation of the form

B(T) = E (1 - b(0Wr )2gt o o By choosing bo-lO-7 C^)2 and If- 2$0degti we can f i t the 0^ and o of a l l LiF (TLD-IOO) strong resolvable glow peaks using only a strong-coupling

12 -1 lattice vibration interaction frequency s = 5x10 sec bull

Analysis of Thermoluminescence Kinetics of CaFMn Dosimeters

n Adam and

T Katriel

Nuclear Research Centre - Negev PnB 9001 Beer - Sheva Israel

Abstract

A new approach to the analysis of glow curves is used to study the

kinetics of the tnermoluminescence of Cal iMn dosimeters Activation

energies frequency factors and related parameters are obtained The

measurements were carried out on the MRLE themoluminescence dosimeters

using a PNH 80] reader in the temperature ranfes 300 - 700 degK The

computational aspects of the analysis are discussed and the computer

program performing the entire analysis using as an input the glow curve

data i s described in the appendix

Introduction

The analysis of thermoluminescence glow curves is a conventional

and powerful method for the determination of activation energies

frequency factors and related kinetic parameters for the processes involved

A new method of analysis has recently been suggested by Haxia e t al

who also applied i t to the thermoluminescence of ZnS and NaRr The glow

curves involved consist of single peaksTt is interesting to apply the

method to a more complicated glow curve The despread use of die

MBLE CaF2Mn dosimeters which have three peaks in their glow curves

as well as the ease with which their glow curves are obtained by use

of the commercial reader made them a suitable example for the present study

Description of the Method

The kinetic equation governing the light emission during a themc-

-luminescence transition is assumed to be

-dnjdt - sexpC-KkTHBjimiVtACN-n^Biiijl (1)

where

m Ccm) is the concentration of holes lying in the ith type luminescent

center

s(sec ) is the frequency factor

E(eV) is the thermal activation energy

A and Bj (cm sec1) are the probability factors respectively fbr

raquotrapping and recombination with the ith type center

N(cm~) electronic trap concentration

n(cm3) i s the trapped electron concentration

k is the Boltxman factor and T the absolute temprature

From this equation the following equation for the line shape of the

glow curve was developed in ref (1)

iog[irr)(cose bull sinescm(s2(T) bull asm)] bull -ECT bull y (2)

I(T) being the intensity of the emitted light at temperature T raquo Tfinal

A laquo I(T)dT and S(T) bull I(T)dT 0 and u are constants Tfinal T

related to the kinetic parameters For the correct value of 6 eq(2)

expresses a linear dependence of

y bull log[t(T)(cose bull sinBS(T)V((T) bull AS(T))] on x - 1T

The numerical analysis involved in obtaining the proper value of 9 is

described in ref (1)

bull A typographical error was noted in eq 23 of ref 1 This equation

should read B bull -keov(xy)v(x) - -kv(y)cov(xy)

- u -

After the right value of 0 has been obtained the activation energy

and the constant u are determined from the slope and the intercept

respectively of the linear curve The ratio AB and the frequency factor

are expressed in ref (1)_ in terns of these partmeters

Measurements and Results

As was noted above the investigated sample was CaF tMn in the form

of a thermoluminescent dosimeter type PNP 292 produced by MBL

The dosimeters were irradiated by an X - ray machine with a maximum

energy of 45 JteV to a dose of about 1000 R The dosimeters were then

heated using the MRLH thermoluninescence dosimeter reader type PMH 801

from room temperature to about 700 K The heating rate i s 45 per

second The glow curves were recorded during the heating period using

a special output provided in the reader The points on the glow curve

were then used as an input to the computer program described in the

appendix the intensity being measured in arbitrary units and the tenprature

in degrees centigrade The rectified data i s represented in figs 23 4

The obtained results are summerzed in the following table

peak I

peak IT

peak III

activation energy eV

120

165

169

peak temp

382

447

536

frequency factor s

S9810

tnW1

414laquo10

AB

237

599

703

The first peak has a particularly low activatio energy which is compensated

with a low frequency factor The roles of the activation energy and the

frequency factor in defining the peaks tenprature can be judged fro

1 2 -

the relation

Esexp(-EkT) - C

where C is a constant depending on som general characteristics of the peak ~

and T is the temperature at the peaks maximum This relation is derived

froa eq 11 of ref 1

Appendix Description of the Computer Program

The glow curve data is introduced as a set of valuesof the emission

intensity versus the corresponding temperatures These are represented

as a linear combination of a few Gaussians in the form N

I(T) x T Ciexpt-OitT-ti)2] = CTf (3) W

The non - linear parameters [ a^t^l are varied in order to optimize

the representation The vector of linear parameters i s obtained as M M

C - S - v where S^ bull T fiCTk)fj(Tv) and Y j - T ICT^fjOi)

The analytic representation i s compared with the experimental data

in fig 1 The analytic representation i s used in order to determine the

rectifying value of 8 hy minimising R bull O-P) p being defined in

eq 22 of ref 1 The appropriate value of 8 is used to determine the

activation energy frequency factor and related kinetic parameters

References

1) V Maxia S Oralis and A Rucci Journal of Luminescence J 378 - 388 (1971)

- 13 -

XS

lt 15

10

I point experimental point raquobulllaquo

350 400 450 500 560 600 650 femp K

Fig 1 Cnonarison of analytic versus experimental flow curve

-10

-15

5 B s ^xxoW Fig 2 Rectified data for peak I of CaF2Hn

- H -

XXmxKT Fiji i Rectified data for peak II of CaF2Hi

0

5 gt c -5

-raquo

-15

1

bull bull bull bull bull bull bull

- bull bull

bullbull bull bull bull bull bull

bull bull

5 IB 17 IB 19 20 2 XXOJxW

Fif 4 Rectified data for peak III of CaF2Mi

- 1 5 -

Fowler

Would the atteapt-to-eseape frequency really be spuriously increased i f the heating rate were so nigh that several true peaks only appeared as one Is this in the right direction Surely Dr Horan said that he obtained s = lo (which i s too high to be reasonable) when his peaks were narrower than expected from simple theory

Adam

I do not think that there is a direct connection between the peak width and

the frequency factor so that one could not say offhand what will be the effect

of widening the peaks on the frequency factor

Mason

In the second slide yon determined E and s from a central portion of the

curve Did you try to determine E and s from the cxtieme parts of the curve

Adaa

Tes we did sone hand calculations but the results were nonsensical

Attix

Did you study natural fluorite or CaF-iMn I believe i t must have been the

fluorite but your t i t l e erroneously specifies CaFgiHn

Adaa

MBIpound gave us the dosimeters saying that the powder within was Caf2lfn If

however Dr Attix says this is their natural fluorite he is probably right

- 16 -

Investigation of

TtTnTrttradeilsclaquollt lithium Borate Classes

using Electron Spin Resonance

by

Douglas ampbull Shearer

Physics Departaont

St Bartholomews Radical College

London

The trapping centres involved in the theraoluminescence of lithium borate glasses have been identified as holes trapped on bridging and non-bridging oxygens in tfca glaa matrix The results of isothermal annealing experiaents indicate that the untrapping process occurs over a continuous spectrum of activation energies The radiation induced 8SR signal froa the glasses with a high alkali content decays fastest except for the anoaalous behaviour of the pure borate glass in which the signal disappears rapidly at room temperature The addition of aanganeae chloride increases the decay rate and reduces the number of trapped teles Manganese occurs in two sites in the glass lattice and their is evidence of this in the thermoluminescent spectrum This spectrum can be altered by the addition of other activators Heavily manganese doped glasses exhibit an additional glow peak at a higher temperature This has been assigned to the transition

Hn + e ^ Mn + hr

which occurs on post irradiation heating

A model has been proposed for the thermoluminescent process in these glasses and some suggestions for the improvement of crystalline lithium borate phosphors have been advanced

Present address Physics Department St Williams Hospital Rochester Kent

- 17 -

There axa aall daflaad probleaa to aolve la tho invntigation of any thaiaalmdashImanaat aubstanoe tha nature and anatier of the trapping and lierlnoananno centraa (anion aay ba aynonyaoua) Bust bo detemlned The kJnetiM leading to the oaiaBlon ara alao isttwrtant Zlntron spin reaonanm la a uaefal tool for laveatigatlBg tfaaaa paranatallaquo In the aaaa of the llthiun Borate group Irradiation Inlnoas a signal ahloh e n ba eoally followed The ouatonr ntivator - divalent bullangenaae - la a paraaagaatla elaaint nhioh giTea a characteristic signal Lithium borate l taalf la atndiad aoat easily orar a aide range of ooaposltlon In tha v i t -reoua atate

PMaauniar

a l l the axperlnantal glaaaea were prepared fraa Analar and Furlaa grade raagaata In a platlnun cro ib lo The firing teaparature aaa 1000degC Mangnnaae and other iasuritlea wars added aa chlorides nitrogen was paaaad through the furnace to ainlniae the quantity of trivalent aanganaaa preaent in the glass All glasses sera aaenohed in eater after 30 aia-ntes in the fornaee

For ESR work the glasses were le f t aa small chunks but for theraoluojlnoanenno atadiea the glass was groand and alaTad to a grain aiae of 80 - 160 aeah 15 aeV aleotrona fran the linear accelerator at St Baiifaoloawwa Hospital ware and for al l tha agpsrlnaatal irradiationa Tha Mcondaiy asiasion monitor deacribed by kotblatv vaa used for the dose callhrationa

Tor a Tslld ooaparlasn of signal helghta f isa different glasses a l l signal heights vara aoml i sed to that of a ruby standard Boosted on tha ooapnaetiag tabe TMa la essential for the range of glasses studied here u dleleotrio I o n la the high alkali oxide glaaaea oan rsdaee signal height by over $0JC The aenaltiTity of tha apeotroaeter vaa aaaaaaad using a known quantity of DPPH la bauana and employing tha standard double inteshygration aethoda auanrised by Poole

ThsraolaaiaeaooBt apsotra vere deterained using the apparatua dee eribad by Harris A Jackson3 anion has a range of 200 - 600 an The appshyaratus desorlbed by Xarsaark at al waa and for a l l quantitative therao-luaiaeaoence Fits to the varioaa kinetics expressions sera done using a IOT-8 ooaputer with a W ferri te core aeaory store

TRArrMJK CHUMS

Ina 13B signals from lrradisted llthlua borate g leans are as bullbona In yig 1 Ths top eight algaals are the original radiation induced spectre The bottom signal i s that mainng after oaraful aonallng

The overlying J and 4 peaked signals havs bean attributed by Grisooa at al to a centre oonaletlag of a hole tiappad on an oxygen bridging between lame and four oo-ordineted borons la the glass structure

The Haailtooian suggested by the above authors for tha structured algnal I s

- 18 -

faring = BCgSH bull g S 2 H 2 bull g SjHj) bull ASI bull A J S J I J bull ASjl 3

with g amp A valnes which wary with eoapoaition

The underlying signal has not baan as thoroughly investigated but i s baliarad by some workers to oe due to holes trapped on non-bridging oxygens

The number of trapped holes i s a function of eoapositiont dose temperatur and raquotorage t iaa The signal i s seen to decay at a l l temshyperatures dona to 77TC - the loaaat investigated I t seems likely that there i s a oontinnous apeotrua of activation energies for the untrapping prooass

Growth curves for the signal are shown in Hits 2 3 The effect of decay i s seen in the difference between tha r i t ive positions of the curves at 7 7 and room temperature

The curves saturate at about 2 x 10 rad when the number of trapped holes i s of the order of 5 x 10 ee after 24 hours s t 77 K Ins number of trapped holes i s independent of pro-irradiation and annealing (See Flit a) This indicates that the traps are not radiation induced

The rate of decay la composition dose and temperature dependent The decay rates of the low alkali oxide glasaes (with tha exception of the pure borate glass) ars least (Pie 5 ) The pure glass deoays rapidly at room temperature The high dose signals decay relatively faster (see Fig 6) Decay curves cannot be fitted by simple 1st or 2nd order expressions However an expression equivalent to that proposed by aedllm for theimo-lominsseent daoay from lerela with a distribution of activation energies gave reasonable f i t s (Pigs 7 8)

T^TwwanwjcE CHTTBES

The usual activator - divalent manganese - gives an E3B signal whieh variea with bass glas- composition and manganese concentration The -iinclaquoTrmdash ion i s more stable in tha lower alkali-oxide glasses (table I )

TABIE I

Intenaityunit sample mass

Intensity manshyganese atom

11

101

1001

12

098001

156002

HJ

097002

231005

14-

1707

5321

15

1501

578035

01

348011

24700

There ara two signals one at g a 2 and the other at g a 4 3 The g bull 2 signals for KT ga mole are shown In Pilaquo 9 Tha change in the g bull 2

- 19 -

aigaal for iaenaaiag aanganeae oancantxation la ahorn in f i n 10 Ina loaa la raaolution af tb hyperfiao atructure at higher eoneentrationa ia dna to dipolar broadening Iha g bull 43 aigaala ara aboan in gtilaquo 11 bdquo A Haalltnnlan for tte g laquo 2 aignal haa baan pmpoaad by Bleaney Snbina i o

^bull-B8JJsect+D[sI2-JS(S1)]AJS-08HJ for S- l - |

a Kadaie et a l baja giaan a HaaUtonian for tha g gt 43 signal produced by iaoalaetnniSfa in lithlua ailioata glaaaea Thia haa been appliad by Lunter et a l to aanganeae in aoaa glassy aatrieea i e

(^f-eBH-S + AVs1 for l - f s -J g-4-3 A- S

These aigaala hare bean attributed to aanganeae in tao different aites in the glass l a t t i ce The doainant g raquo 2 signal oorresponda to aanganase in an axially ajaantile alta The aigoal at g = 43 i s aaaosiated with rhonbio ayaaatry The tao aites concerned oan be tentatively identified aa aanshyganeae in netwoik aodifying and network foraing poaitiona

Carina oopper and iron have also been added aa obloridea The only ESR aignal raquoas aaen at g s 43 froa iron Thia haa been attributed toferric iron in aa orthorhoabio eleotroatatic crystal field (Caatner et

MB tTTECT Cf BAPIATigi CH THE ESB SIMM HOT DOFSB 6IASSTS

I t ia found in these glaaaea that the nuaber of trapped holes after irradiation i s l e ss than in the undoped glasses - the greatest decrease being Man in the glasses with tha suet added iapurity (Pine 12 H i

12 Theas results are ooapatible with those obtained by eriaeon et al which ahoa that halogen Vk oentea ooapote for liberated holes with the boron oxygen centrea thua raduajtng the oharactaristio alkali borate radiation indooed signal The rata of decay of tha aigaal ia also increased in the doped glaaaea (Flu 14) Thia will also decrease the effective nuaber of trapped holea

THMifllfflllaiBBfflWT SPBCTBA bull

Tharaolnminaaeont apaotra have bean obtained froa pure and doped glassee The nonaotiTated glass spectra are siailar to those of the nore lightly aanganeae doped glaaaea Thia iarliee that lualnesoeaoe in undoped glaeaea ia due to traoea of aaaganeaa These spectra peak at approziaately 620 an The spectra were aubatantially the sane for tha two hole traps which ladieates that the lnainosoonoo oentre la the sens ia both cases Within tha l i a l ta of tha experlaant no dependence of tht apaottua on dose w observed The tbtraolualneaoent apaotrua aoved towarda longer wavs-langtbe tin greater the oonoentration of aanganeae Aring aubaldlary feature la tha apeotruB of tha pure lithloa borate glassea waa a aaall peak at about 47$ an ( f lu 1Sgt which waa aore obrlotlaquo In tha lower alkali oxide glasses la addition the pore 01 glesa aotivated with 10 ga nole aanganeae showed

a peak at 5J0 an In the 15 glass doped with 1 0 ^ ga BO another aaall peek ma observed at 220 mu Thia caa only visible on to lag aeala ( H g l l f i ) Theaa apeetra a n raquolightly twperature dependent -the emission shifting towards the shorter wevalengtha on inorease of tea-perature (Table I I )

TABLB II

^ ^ S l a a a Temp Coapositien Bang

Peak(au) 77degK^Eooa leap

With (an)

Peek(att) Eooa Temp- 200 C

Width(au)

bdquo Fek(mu) 200 C-raquo laquo raquo C

fidth(mu)

11 lO

615plusmn15

550-710

610+10

5VO-700

61010

535-700

12 10-

620+10

560-700

615+10

560-690

63020

$20-690

13 10

640+10

570-710

6305

570-695

14104

6W+10

535-720

6305

575-710

625+5

570-700

15 10

61010 (5 tr -70O ( Peaks (A B C 6gtraquolaquo0-C70

615 10

555-710

610 5

55-695

01 10 -

6105 ( 5 0 laquo 7 5 ( Feaka ( A B (530~laquo5

610 5

560-675

610 5

560-680

J3 10 4 It baa keen shown (Blnghsa Parka tanter at al ) that the aaiasion peaking at -620 an ia aasoaiatad with nangsneae in ootahadral coshyordination alille manganese In tetrahedrally sjenil i lo surroundings gires rige to a green emission (approximately 530 an) I t has alao been noted (tajl 7 that the orange emission ia omenohed at higher teaperatores while the green ia relatively unaffected Thia amy explain the temperature effect aeon in the apaetxwa of swat glasses

the predominant emission at about 620 an and the 530 an amission hat been explained (Kedlin1 Bingbam 4 Parka1 ) as due to the K^ (T J laquo Ss (A1J tranaitlon - the differenoe ia wavelength being dna to the ayueetry change There ia a probability of the 4 (T ) - 6pound (AJ

transition abieh oould gire rime to the obserred emission at about 450 an -the higher lerels giring rise to the shorter warelength emissions

(Fin 17V (Curiatrade)

Whan doped with oeriua and upper the spaotrua ia altered aa shown The blue luminescence for oeriua at 385 au ha been attributed

to a transition between the doublet levels

S ^ ^ 1 7 Konoslent oopper i s reported (Xarapetyaa1) to give an emlaaion about 500 an and the sbsense of any 18H apootma n infonea this olusion The sopper apeutium ia extremely tmdashporalius dependant

at

- 21 -

Bassilaquo The tiieraoluainBscent eaiasion oan be examined aa a function of

SSJt signal height by step annealing individual glass saaplaa The resultant plot la not completely linear in a l l oases This i s not surshyprising in view of the tao contributory traps and the spectral shift with temperature Plots for two glasses are shown in Fine 18 19 The relationship i s significant enough however to assign the glow peak in these glasses to the hole traps observed by ESR

The glow curves are shown in f i g 20 Data are given in Table III

TABIB III

bullmdash__Jgtoae Composition mdashmdashmdash^

deg2 B2 deg3

L 02 BjOjIO- ga Vole lb

10 - 3 bull

102

101

107rada

190 + 8

200 + 8

141 8

Low tamp High temp 150 + 8 278 + 8

Low temp High lamp 138 + 8 265 + 8

106rado

168 + 8

163 + 8

1 laquo + 8

lO^rada

168 + 8

155 + 8

155 + 8

138 + 8

lO^radt

150 + 8

150 + 8

157 + 8

I t can be seen that increasing manganeae concentration gives riae to a higher temperature glow peak After irradiation these glasses have a purple t int due to Kn Tola disappears at the higher glow peak tempershyature The peak may therefore be correlated with the transition

e + Hh - gt bullraquo + hv

The actual glow peak temperaturaa are dependent on composition dose time and temperature of storage

Tiieraolumlneseent response eorvea are ahown in Elg 21 These are for undoped glasses The low responses for the BjO and UJOBJO glasses are due mainly to the laek of trapped holes With the addition of 10 ga bullale manganese la each glass the results are aa shown in Fig 22 These results oan partially be explained by better activator efficiency and trap stability in the low alkali oxide glasses The response curves for the _ manganeae activated 12 glasses are shown in Tie 23 The peak for the 10 ga mole activate glass sen be explained as the beet compromise between number of effective activator atoms and number of trapped holes The resshyponse curves due to the other aotivators am as shown (Jja_2a) The

- 22 -

increased responses due to oopper and oeriun are primarily due to tho change In emission speotra That tho above considerations ara not tho whole story la shows by Fin 25 l raquo tho number of observable trapped holes and luminshyescent centres do not entirely determins tho thermoluminescent outputlaquo Con-oantration onenohing meohsnisms are almost oertslnly involved in tho more heavily doped glaases and difforaneoa in energy tranafar propertiea of the base glosses may be important

MODEL FOB THgarcmimiBscmcK

Ihe above experimental data lead to a Model with at least tao hole traps These trapa hare a distribution of aotiTation energies The traps are not dependent on radiation formation added impurities provide additional trapping oentraa The lnadneaeent centre i s independent of the trap and the Mission spectrum can be altered by changing actiTators So far i t haa not been possible to determine whether eleetrona or holes are entrapped but a simple model assuming electron unt rapping i s shown in Pilaquo 26

The high tempersture peak in the heavily manganese doped samples can be pictured aa a result of the prooees shown in Fig 27

COHCUBICBS

From the sbcTe data it would aeea that the most efficient manganese activated phosphors are those in which the alkali oxide content i s ss low ss possible and which are prepared under reducing conditions As halogens appear to be responsible for decreasing the number of useful trapped holes the manganese should not be Introduced as the chloride Manganese acetate would serve Urn purpose of eliminating the competitive traps I t would also help to reduce the manganese to the divalent state

Preliminary preparations of crystalline lithium borate phosphors have been carried out along these l ines with good results

An sltemative method of increasing the effeetive effioienoy i s to shift the emission spectrum This can be achieved by doping with activators giving emission spectra in the shorter wavelength region

As the ISR signals from orystals appear substantially the same work i s being carried out to extend these ideas to the range of eryatalline phosphors

- 23 -

REFERENCES

J Rotblat Natura (London) 175 745 (1955)

CP Poo llaquo Electron Spin Reaonance ( i n t e r a e i e n c e ) (1967)

AB Harris 4 JH Jackson CEGB Report RDB1I111 (1968)

CS Karimark J I h i t a and J F Fowler Phys Med B i o l 2 273 0964)

P Beekenkanp P h i l i p s Reaaarch Report Supplements No 4 (1966)

DL Grieeoa PS Taylor PF Ware A PJ Bray

J Chelaquo Phys 48 5158 (1968)

WL Medlin Phys Rer laquo3_ 502(1961)

B Bleaney A RS Rutine Proo Phya Soc JJ 103 (1961)

RW Kediie DH Lyona A Kestigian K Phys Rer 138 A(918) (19B)

SG Lunter C O Karapetyan NB Bokin A DM Yudin Soriet loyales - Solid State 9 2259 (1968)

T Ceatner G Newell N Holton A C Sliohter J Chelaquo Phys 2 668 (I960)

DL Griaeoa PS Taylor A PJ Bray J Chan Phya 50

977 (1969)

K Binghaa A S Parka Phyaiea A Cham of Glass 6 224 (1965)

WA Weyl Coloured Glasses (The Society of Class Technology)

(1951)

I L Medlin J Opt Soo Aner pound J 1276 ( 1965 )

D Curia Traquollaquo1neioenoa in Crysta l s llethuan A Co Ltd (1965) 0 0 Karapetyan IZT AKAD NAUK SSSR SER FIZ 2g 539 (1961)

- 2 4 -

RADIATION-INDUCED ESR SPECTRA OF LITHIUM BORATE GLASSES

i-tn MBi 2-WC 9

Fig 1

DOSE RES PONSE CURVES OF PURE LITHI UM BORATE GLASSES AT 77deg K

10 bull

sect W in bullI Vgt ui

i 3

Kgtl bull i i i W W raquo W TO

DOSE (RADS)

Fig 2

- 2 5 -

gw

DOSE RESPONSE CURVES Of PUK LITHIUM raquoCRA1E GUSSES

AT ROOM TEMPERATURE

bull 1 1

bull 1 = 2

3 - g i ^ ^

J ftr-

Fig 3

O Vira in FvwiMabJnatfiMi

i ^ S D

reg lslaquoUlaquo

4r

t

raquoraquo raquo 3 i OMflraM

raquo g

Isl IKRIVATIVE E S R SIGNAL HEIGHT

N0RMMISE0TO INITIAL HEIGHT

I l 4 DERIVATIVE E S R SIGNAL HEIGHT NORMALISED

TO INITIAL HEIGHT 9

I

I

- 2 7 -

CUttS M i raquobullbull

mon ranwruK KCAV OF cwrositwlaquo u t ^ ras n a i euss M S - raquo I gMOS t - a bull bull L I

nlaquo 6

- 2 6 -

UDft |01 la4RHgtMliHll _

si s- M

V R J O J IB gm bull Mn

T

|0raquo|0) bull bull - - bull bull bull bull bull -

n 9-

ESB WBWtKAT bull - FOD UIOLAW WHH raquo K B E N T FKOKRtTMM

M t c - m mdash raquo iju=o-raquo

^ A bull s

-

x ltraquoVn 1- HMlaquo Hu UfO raquo(DfUT1 ftlaquolaquo

ris lo

- 2 9 -

E8R S n i U k U A T f - 4 FC li 1 GLASS ACTIYATEDWITH DIFFERENT

- 3 0 -

ENfCr O ADOID WMKaringaringtM ON L M DQSf bull

laquornooM Jtmmmm

i

I I 1 sect 3 i

I t

l

i r B

I

ltt

rf laquo f

raquo

- tf

i f

i i 1 1 raquo raquo raquo

Fig 12

- J l -

IKICT V raquo i l v WEMHT ADHB ACTIVATOII ON I U OOU HMftWS OF I I CUtSSAT ROOM TWHUTUM

51 i 1

I K

Ml (raquobullraquogt

Pig 13

DECAY RATES Of IRRADIATED MANGANESE ACTIVATED 14 GLASS AT ROOM TEMPERATURE

1 Tzzia

k 2 I

KgtgmimhraquoMn

^

raquo-raquo

I Hi

MimrtH at M M tamp

f i 14

32

- 3 3 -

DOm WITH raquo - laquo raquo bull HOUt HAMCAHUI

bull jplusmnplusmnjraquojioiiiplusmn plusmn

ti- 16

- 3 4 -

Pig 17

PLOT OF LIGHT IN GLASS AS A FUNCTION OF 1st DERIVATIVE E S R SIGNAL HEIGHT

FOR M COMPOSITION

bullbullORONHTPERFINEFEAK

bullASYMMETRIC FEAK

bull bull I -J O gt 4 0 K 100

OF 1st DERIVATIVE E S R SIGNAL HEIGHT

Pig 18

- 3 5 -

n a OF LIGHT IN MASS AS A FUNCTION OF

MDOIIVATIVELSIL SIGNAIHEICHTFClaquo 15COMPOSITION

bull bullOMNHVFFJFIHEFEAr

bull ASVMCntlC PEAK

r

raquoCf lUOfHIVAI IVELS i l SIGNU WIGHT

Mg 19

CLOW CURVES FOR IRRADIATED III LITHIUM BORATE

Tig 20