2001 high sensitivity thermoluminescence dosimetry a.j.j. bos

of 26 /26
High sensitivity thermoluminescence dosimetry A.J.J. Bos * Interfaculty Reactor Institute, Delft University of Technology, Mekelweg 15, 2629 JB Delft, The Netherlands Received 23 February 2001; received in revised form 30 April 2001 Abstract This paper reviews the physics of the phenomenon of thermoluminescence TL) related to dosimetric applications. Basic concepts are given using the simple model of one trap±one recombination centre. General characteristics of thermoluminescence dosimetry TLD) materials are reviewed. Two high sensitivity TL materials are discussed in detail namely LiF:Mg, Cu, P and a-Al 2 O 3 :C. What is understood and what knowledge is still lacking of the TL mechanism in both materials is indicated. Field measurements show that in spite of incomplete understanding of the TL mechanism, both materials can be used to measure very low doses in a reliable way. Ó 2001 Elsevier Science B.V. All rights reserved. PACS: 78.60.K; 87.56; 87.53.B Keywords: Thermoluminescence dosimetry; Sensitivity; TL materials; LiF:Mg, Cu, P; Al 2 O 3 :C 1. Introduction The phenomenon thermoluminescence TL) has been known for a long time. The ®rst application of this phenomenon for dosimetric purposes was from Daniel et al. [1]. Since then much research has been carried out for a better understanding and improvement of the material characteristics as well as to develop new TL materials. Nowadays, thermoluminescence dosimetry TLD) is a well- established dosimetric technique with applications in areas such as personnel, environmental and clinical dosimetry. TLD is based on materials which after expo- sure to ionising radiation) emit light while they are heated. It is believed that the impurities in the TL material give rise to localised energy levels within the forbidden energy band gap and that these are crucial to the TL process. As a means of detecting the presence of these defect levels, the sensitivity of TL is unrivalled. Townsend and Kelly [2] estimate that the technique is capable of detecting as few as 10 9 defects levels in a specimen. To put this num- ber into perspective one should realise that de- tectable chemical `purity' in a sample is six orders of magnitude higher. The high sensitivity, on the one hand, allows the determination of very low radiation doses. Several examples of it will be given later in this paper. On the other hand, it hampers us in investigation into the relation be- tween the luminescence and the defects involved in Nuclear Instruments and Methods in Physics Research B 184 2001) 3±28 www.elsevier.com/locate/nimb * Tel.: +31-15-278-4705; fax: +31-15-278-6422. E-mail address: [email protected] A.J.J. Bos). 0168-583X/01/$ - see front matter Ó 2001 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 5 8 3 X 0 1 ) 0 0 7 1 7 - 0

Embed Size (px)

Transcript of 2001 high sensitivity thermoluminescence dosimetry a.j.j. bos

  • !"

    !

    " !! # ! ! $"%& !!

    ! ! !' (

    $"%)& # "# "%

    %*+, -, . /0*- 1

    # 2# 2 "% # ! ! "% ,

    # # 3 4 5

    #$%&' 6789 76:8 76:

    ("' " 4 "% %*+, -, . 0*-

    " ! $"%& 2# " ; !!

    ! !! # )

  • ! A "%) !! !

    " !! # ! ! "% # !! 2 D , ! "% # >@, "%) /# , # # / "% %*+, -, . 0*- # # @ / !!

    " # K "% A 2 # "%) !

    + # @

    2 "% !!

  • # !! A # # @ / $# # / & " @ $ & " ! $7 & / #, / ! !!* " $ & " ! ! ! ?,

    @!

    # . ! ! " ? !//! A ! / $ ! !

    ?, E ) ! ! , / ! $ & " * ND / 786 : 5F9, ! A ! ! , # ! , !! # ! , @! # @ !!

    !! , / !, ? !!

    !! ? # " , !! !/! ! /?/ " ! ? # !, !/ ? $ @! & # ! # /! $! &, @ 3? $& # ", /? # @ ; !, !/ )

    " ? ! !

    ! "% " # ! !! # # ! " / A ! # @ / ! # ?, "% " "% ! ! !! / A !! "% / #

    3 #

    "% ! #/ * $& /

    $& !!

    $& $& /

    4 , ! % "

    !, ,

    $--- 0 !- - " - #- - 12 3445 6/1 :

  • # ! ! ! ! / " # !!/ +,

    # $ !

    @! ! # ! !" !! ? !!,

    # ! ! ! !! %2# ? !! ,

    3? $&'$& O !! / ! "% ! ? 3? $&'$& "? "%! " / " ! @! ! ! /! !

    E

    " ! - +9

  • ! # # ! ! 0 # ! , # !2,

    ; @! [email protected]! & ", ! , @/! ! , # ! , # / )

    " !! '12 ? A $& ## :

    # 5, 9 2! A

    ! !2 @, , ;@ " ;/ "% " @ $, # &

    @!

    A ? !! # # ! $& !2 @ ! !/! A !!

    .! '1 ;/ "% ?, #* $& # !! $& # ), $& # , ! ? $& # , . * 5 9 # ! # 2!

    $--- 0 !- - " - #- - 12 3445 6/1 6

  • ! ! ! ! !! A ! # !2 ?

    N A $& )

    7 5 ) !2 ! # / # 2! $ & 4 $ $&& # !! #* !2 # !# # A $& !2 ! # # L " @! !! 3? $& A ## ! / ) ? ! ! " !/! ! ;@ !!

    !! " # !/ @!

    / A/ # "% # # # !2

    " 3? $& ! / -

  • A
  • E @!

    @!

    7# 3? $E&

    --6- 8*" " ;/ / "%

    ? # !;,! ! #, # ! ! , "% !2# ; ;/ / 2+ .

  • !! ; ! # !2 # M ? ! 2 # "% # # ! '12 $3? $&& (2'( $3? $8&& !, ! ! ! #, ) 3? $& $8&

    ; ! 2 !

    ! # !! / # $ :$&& @ # / # " ! [email protected] " ! ! # # P !/ @! "%

  • #,

    ; !!'12 "%! " $ & # ! # # !! ! , ! '1 @! ) # !2

    "%) $!! #, !, 3? $&, ! / !2 # /! # ! ! ) " " / ;

    @!

    " ; 3? $& # , # 8, ) # / # !20 , .

  • , @! "% -/!%40: " !! # / "%

    !!/

  • @ ! '1

    # # !! '1 ? # " A # @!

    # ) !2 , !2 E " !2 #, # !2 , , /;/ , !2 !/ ; !2 ;@ !2 E !2 @ # /! $ B& "!! ! !2 # "% # ! # ;@ /! " @! # ! ;@ ! / ! $ & !! !/

    # 5 7 B " @ # " !2 4, !2 , ! @!$/ M & # !! !/ ; !) K ! ? " # !

  • " ! "%

    #, # # !! ? " ?/ ! !! "%) !! ; # # / $ " & A "% / A 4 E # !! # "%

    6-- &

    " ! "%) ; "% $!2 "% / ! /& ! ! 0 , ; , ! ! / " ! , 3! O / $ /;, ! ; O& O "/ , ;

    ! "% / # "% %$"%)/&, # ! "% ?! !! /

    "% #, , /! "% K "% ' @!, ! $/ !/, !#,

    , !, 2 !& !! /! ! / A # %3" $!, !& # "% %3" $! !, & " 8- $ : +5& #

    6-- .

    " "% A # !

    # !! #, / ! # / M ! /? ; !, ! ; !! ! " ! $ ! @& ;

  • 6-6- ) .

    A "%) !! !! $ " & "%) ! ? !! 4!! "% @! ! # K ) P !? "% "% #

    "% "%

    # "% ! O/ "% A "% /! , @! ! # ) ? # ? #

    "%

    "% E

    # ! /; A ! "%

    A 25 # A '25 , #, / # A / ! M " ! !

    ! O [email protected] E A ! # # # ! M ;

    :

    # # " + # ! E, # :

  • A ! ! /! !; ! ! # $ 25& ! : +5 ! 8-

    6-2- $ 9

    0 ! "%) ! "% " "% ! !! ! ? " !// ! ! #

    !

    4 # # /! $ & " !/ !! ; ! ! !! /, "% N4, / ? # @ / ) / ? ! 2 !!

    , /! !, , !" # ! , , K/ "% !2

    ! * 8, 0* 68 6:

    A-P/ * , -* , >* :, 0* 6B >* 7, +* , .* , 4* :, 9* 68

    A-./2 * 8, -* 67, >* 66, 0* 6:E7, >* 6:, +* B,

    .* 7, 4* E, -* 6B, 9* , -* , * E, S* :

    68:

    1 0 * B, 0* 777 6:

    -* E, >* 6::, 0* 7, * 7 666

    % %* 86:, * 6: 7

    0 * E67, 0* :B 7

    40 0* :, 4* E86 6:

    -! * E6, -* EE, >* E, 0* EE8, +* , .* :, 4* , -* BB, S* :B

    -40E 0* E6, 4* 8, -* BE :8

    - -* :, * E786 8B

    $--- 0 !- - " - #- - 12 3445 6/1 6

  • ! ? # #

    A %$"%)/& #

    M "% / !! ! , ; "% / !$ !, /& A 2 ! # M "% "% ! 2! ! " ! ; # /

    @! ! # M "% /, A 2 / # 2 ! ; !!! !;/ 2 / 2

  • / A , !? ! @! 0 !

    # ! ! ? !! / # 2 !

    6-:- # + ;1