CsI (Tl) V È° Ë Ñß e È û s ÚM 8 ý P c p Ò Å Ä Z Ø° Ë Ñ ¤V R Ë ì Å
-
! H¬ £ G B ∗
â
l @ / < Æ § Ó ü t o < Æõ , Ã º" é ¶ 443-760 (2006¸ 1 Z 4 13{ 9 ~ Ã Î6 £ §)
Bridgman é ß & ñ $ í © Ð\ ¦ s 6 x # CsI (Tl)é ß & ñ ` ¦ $ í © r ( Ü ¼ 9 s \ ¦ s 6 x # $ 3 F g Ø ¦ l \ ¦ ]
j ¦ y ì rF g: £ ¤$ í ` ¦ ¸ % i . $ í © ) a é ß & ñ _ ß ¼l H f â 10 mm, U ´s 10 mm s ¦
Ö
¸$ í ] j_ 0 l x ¸ H 1000 ppm s % 3 . s [ þ t é ß & ñ ` ¦ bialkali F g 7 £ x C ' a, multialkali F g 7 £ x C ' a x 9
F g s ¸× ¼\ ¦ s 6 x # ~ ½ Ó Ø ¦ l Ð ] j ô Ç Ê ê,
22Na,
137Cs,
60Co ³ ðï r y " é ¶ \ @ /ô Ç \ - t
ì r K 0 p x` ¦ y y 8 £ ¤& ñ ¦ q § % i . Õ ª õ CsI (Tl) Ø ¦ l _
137Cs_ 0.662 MeV y \ @ / ô
Ç \ -t ì r K 0 p x É r bialkali F g 7 £ x C ' a _ â Ä º 8.5 %, multialkali F g 7 £ x C ' a _ â Ä º 7.7 %, F g
s ¸× ¼_ â Ä º 7.5 % \ ¦ % 3 % 3 .
PACS numbers: 29
Keywords: Bridgman é ß & ñ $ í © Ð, CsI(Tl)$ 3 F g Ø ¦ l , F g s ¸× ¼, F g 7 £ x C ' a , \ -t ì r K 0 p x
I. " e  ] Ø
í
H Ã º CsI$ 3 F g ^ \ Ö ¸$ í ] j (activator)\ ¦ & h ] X y ' r v
þ j@ / ~ ½ ÓØ ¦ © (wavelength of maximum emission)
÷
r ë ß m F g ´ n uÖ ¦ (light yield) ¸ oô Ç . s Qô Ç :
£ ¤$ í É r Ø ¦ l \ ¦ ] j H X < × æ כ ¹ô Ç « Ñ ÷ & H X < $ 3 F
g ^ _ ~ ½ ÓØ ¦ © É r F g 7 £ x C ' a` ¦ & ñ H X < Õ ªo ¦ F
g ´ n uÖ ¦ É r Ø ¦ l _ ì rF g: £ ¤$ í \ % ò ¾ Ó` ¦ p u l M :ë H s
.
Ö
¸$ í ] j\ ¦ ' t · ú § É r í H Ã º CsI$ 3 F g ^ _ þ j@ / ~ ½ ÓØ ¦
© É r 305 nm s 9 F g ´ n uÖ ¦ É r 2,000 photons/MeV s
. CsI \ Ö ¸$ í ] j Ð thallium (Tl)` ¦ Å Ò{ 9 Ù þ ¡` ¦ â Ä º þ
j@ / ~ ½ ÓØ ¦ © É r 540 nm Ü ¼ Ð F g ´ n uÖ ¦ É r 65,000 pho- tons/MeV Ü ¼ Ð y y 7 £ x ô Ç [1].
: r ½ ¨\ " f H í H Ã ºô Ç CsI_ $ 3 F g ´ òÖ ¦` ¦ Z } s l 0 AK '
H # Q t Ö ¸$ í ] j× æ ´ òÖ ¦ s a % ~ ´ ú §s 6 x
¦ e H כ Ü ¼ Ð · ú 9 thallium ` ¦ ' # CsI(Tl) é ß
& ñ ` ¦ $ í © r v ¦ Ø ¦ l \ ¦ ] j % i . é ß & ñ É r
É
r é ß & ñ $ í © © u \ q K q §& h ç ß é ß ¦ $ í © r v l
6 x s ô Ç Ã ºf Bridgmané ß & ñ $ í © © u \ ¦ z ´+ « >z ´
\
" f ^ ] j # é ß & ñ ` ¦ $ í © r ( . Õ ªo ¦ # l
"
f % 3 É r é ß & ñ ` ¦ bialkali ü < multialkali F g 7 £ x C ' a Õ
ªo ¦ z ´o B H PINF g s ¸× ¼\ ¦ s 6 x # ~ ½ Ó Ø ¦ l
\ ¦ ] j ô Ç Ê ê
22Na,
137Cs,
60Co _ γ³ ðï r " é ¶ \ @ /ô Ç
∗
E-mail: [email protected]
\
-t ì r K 0 p x` ¦ 8 £ ¤& ñ # Ø ¦ l _ ì rF g: £ ¤$ í ` ¦ ¸ q
§ % i .
II. ÷ m Ç ] M ö
1. S z »8 ý Ç U ØR õ m Í m+ s ÇX N Ë V R ËX ê s é
ß & ñ $ í © ` ¦ 0 Aô Ç r « Ñ H Aldrich Chemical Co. _ CsI (99.9 %) ü < Ö ¸$ í ] j Ð H Tl (99.999 %)` ¦ 6 x % i
. Ö ¸$ í ] j 0 l x ¸ H 1000 ppm Ü ¼ Ð D ¥ ½ + Ë # 6 x % i .
r
« Ñì r ´ ú ` ¦ V , l 0 Aô Ç $ 3 % ò ¸m H ? / â 12 mm, ¿ ºa 2 mm, í H ¸ 99.9 %_ $ 3 % ò ' a` ¦ s 6 x # ] j % i .
Bridgman $ í © Ð_ â Ä º } f & ñ (seed crystal)` ¦ 6 x
t · ú §l M :ë H \ $ 3 % ò ' a _ ô ÇA á ¤ = å Q Â Òì r` ¦ 45
◦_ y
¸ Ð ¶ ð7 á ¤ > ë ß [ þ t% 3 Ü ¼ 9 r « Ñ\ ¦ V , ¦ / B N x 9 4 x (10
−3torr)` ¦ ô Ç Ê ê 6 x % i .
6 x ) a à ºf Bridgman é ß & ñ $ í © © u H z ´+ « >z ´\ " f
^ ] j ô Ç $ í © Ðs . ½ ¨ ¸ H r « Ñ / B N 4 x{ 9 ) a $ 3
% ò
¸m \ ¦ l Ð (electric furnace)5 Å q Ü ¼ Ð ? / 9Å Ò H y ©
l # Q © u ü < r « Ñ\ ¦ \ P # 0 l q # Å Ò H \ P © u Õ ªo
¦ & ñ x 9 : r ¸] j# Q © u [ j  Òì r Ü ¼ Ð ½ ¨ì r ) a . y © l # Q
© u H D.C.15 V, 5 rpm _ è+ þ A$ 5 Å q l # Q ¸' ü < y 5 Å q l
#
Q\ ¦ s 6 x # r ç ß { © 1 \ " f 10 t 5 Å q ¸\ ¦ or
~
´ Ã º e . ] j ) a é ß & ñ $ í © © u l Ð_ : r ¸ H þ j
¦ 1,100
◦C t ` ¦w n = Ã º e % 3 Ü ¼ 9, s l Ð H & ñ x 9 1
l
x : r ¸ ¸] X © u ü < Pt-type_ \ P © (thermocouple)` ¦
-96-
# & ñ $ í © r ç ß 1 l x î ß { 9 & ñ ô Ç : r ¸ 621 ± 1
◦C
\
¦ Ä »t > % i . $ í © ` ¦ 0 AK $ í © Ð\ © l
Ð _ CsI (Tl)ì r ´ ú ` ¦ 4 x{ 9 ô Ç Ã º& ñ ' a Fig. 1(a) õ Ä º8 £ ¤
\
H Bridgman é ß & ñ $ í © Ð Fig. 2(b) \ Ð# & .
2. V È° Ë Ñß e È û s ÚM 8 ý < gX c l
CsI (Tl) é ß & ñ $ í © r thallium (Tl)_ 0 l x ¸ H 1000 ppm Ü ¼ Ð × þ % i . Õ ª s Ä » H Ö ¸$ í ] j 0 l x ¸ à ºÑ þ ppm t H $ 3 F g ^ _ ~ ½ ÓØ ¦ Û ¼& 7 à Ô! 3 s ¸ ú t · ú §Ü ¼ 9 1000 ppm Â Ò H \ " f þ j ¦_ ~ ½ ÓØ ¦ Û ¼& 7 à Ô! 3 ` ¦ ? / l
M :ë H s [2].
F
g 7 £ x C ' a õ F g s ¸× ¼_ ½ ÓA á ¤ õ ] X 8 ú ¤ H CsI (Tl) é ß & ñ ³ ð É r F g È Òõ $ í ` ¦ a % ~ > l 0 A # Ó ü t \ ] X
É r tissue ü < · ú ï` ¦` ¦ s 6 x # % o % i . ¢ ¸ CsI (Tl) \ " f F g 7 £ x C ' a x 9 F g s ¸× ¼_ ½ Óõ ² ú ¢ H
` ¦ ] jü @ô Ç ¸ H ` ¦ ü @Â Ò Ð ~ ½ ÓØ ¦ ÷ & H y n C_ < Hz ´` ¦ F G
è o l 0 A # 30 µm _ Al
2O
3ì r ´ ú õ [ j : r` ¦ [ O # Q
} 9 > (rough) ³ ð % o \ ¦ # Å Ò% 3 . s X O > % o ô Ç CsI (Tl) é ß & ñ _ 2 ; ³ ð \ _ á Ô : r _ { 9 ` ¦ y " f ì ø Í
` ¦ + þ A$ í r ( [3].
Ø ¦ l ] j \ H bialkali ü < multialkali ¿ º 7 á x À Ó_ F g
7 £ x C ' a õ z ´o B H F g s ¸× ¼\ ¦ 6 x % i . Bialkali F
g 7 £ x C ' a É r EDIT company _ B50B01` ¦ 6 x % i Ü
¼ 9, multialkali F g 7 £ x C ' a É r Hamamatsu _ R5070 F
g 7 £ x C ' a` ¦ 6 x % i . F g s ¸× ¼ H 10 mm × 10 mm ß ¼l _ Hamamatsu_ S3590-01` ¦ 6 x % i .
F
g 7 £ x C ' a _ { 9 ½ Óõ é ß & ñ _ ] X 8 ú ¤ \ " f Ï ã J] X Ö
¦ \ _ ô Ç y n C_ È Òõ $ í ` ¦ Z } # Å Òl 0 A # F g 7 £ x C
'
a õ CsI (Tl)é ß & ñ s \ È Ò" î ô Ç z ´o B H F g < Æ ½ ¨o Û ¼ (silicon optical grease : Ï ã J] X Ö ¦ n=1.14) Ð × æ ç ß \ # QÖ ¦a Ë >
Fig. 1. (a) Quartz tube with CsI (Tl) powder and, (b) Bridgman single crystal growing system.
8
£
x` ¦ + þ A$ í r & Å Ò% 3 . ¢ ¸ F g 7 £ x C ' a É r t l (fë Ã) \ _ K [ þ t s â Ð\ " f s » 1 Ï÷ &# Q Ò q tl H < Hz ´` ¦
×
¦ s l 0 A # µ - F K5 Å q` ¦ (0 > Å Ò% 3 .
F
g s ¸× ¼\ ¦ s 6 x ô Ç ~ ½ Ó Ø ¦ l _ ] j É r Fig.
2(b) ü < ° ú s ß ¼l 120 × 80 × 120 , ¿ ºa 6
_ · ú À Òp ³ o u © \ E Z O 7 £ x; ¤ l (preamplifier)ü < F g s
¸× ¼\ ¦ < Êa [ O u % i . © _ 0 AA á ¤  Òì r É r ~ ½ Ó s
[ þ t # Q ¸ H t 2 £ § 20 _ " é ¶+ þ A ½ Ó` ¦ ë ß [ þ t ¦ · ú À Òp ³ o u ~ Ã Ì (Aluminum foil) Ü ¼ Ð (0 >Å Ò% 3 . é ß & ñ ` ¦ bialkali (K- Cs-Sb), multialkali (Na-K-Cs-Sb) F g 7 £ x C ' a[ þ t õ z ´ o
B H PIN F g s ¸× ¼\ ¦ s 6 x # ~ ½ Ó Ø ¦ l \ ¦ ] j ô
Ç Ê ê
22Na,
137Cs,
60Co _ γ ³ ðï r " é ¶ \ @ /ô Ç \ -t ì r K
0 p x` ¦ 8 £ ¤& ñ # Ø ¦ l _ ì rF g: £ ¤$ í ` ¦ ¸ % i .
3. P c p Ò Å Ä Z Ø° Ë Ñ ¤V R Ë ¤X N Ë
CsI (Tl) ~ ½ Ó Ø ¦ l _ y ì rF g: £ ¤$ í ` ¦ 8 £ ¤& ñ l 0
AK ¿ ºa 50 mm ± ú # 4 [ t Ð ß ¼l 350 × 350 × 450 _ ` / B N ç ß ` ¦ ë ß [ þ t # Q ½ Ó~ ½ Ó (background radiation)` ¦ ` r ( . ì rF g: £ ¤$ í ¸ \ ¦ 0 Aô Ç Ø ¦ l ü
< ~ ½ Ó " é ¶ s _ o H 50 s % 3 . E Z O 7 £ x; ¤ l (preamplifier) H Canberra 2004` ¦ 6 x % i Ü ¼ 9 Å Ò7 £ x; ¤ l
(Canberra 2021)_ ` O Û ¼+ þ A$ í r ç ß É r 2 µm \ ¦ s % 3
Fig. 2. Structures and pictures of CsI (Tl) detectors with
PMTs and photodiode. The CsI (Tl) single is 10 mm in
diameter and 10 mm long.
Table 1. Energy resolution of detectors.
Gamma - ray Energy
22Na
137Cs
60Co
Detectors 0.511 MeV 0.662 MeV 1.173 MeV 1.332MeV
Bialkali PMT 9.2 % 8.5 % 7.2 % 5.5 %
CsI (Tl) Multialkali PMT 8.9 % 7.7 % 6.6 % 5.1 %
Photodiode 8.7 % 7.5 % 6.2 % 4.8 %
¦ y Û ¼& 7 à Ô! 3 É r 600 sec1 l x î ß ¾ º& h r ( . ¦
· ú
/ B N/ å L © u (Canberra 3102)\ ¦ s 6 x # bialkali F g 7
£
x C ' a \ H s # QÛ ¼ · ú ` ¦ +1000 V Õ ªo ¦ multial- kali F g 7 £ x C ' a \ H −1000 V\ ¦ # Q Å Ò% 3 . F g s
¸× ¼\ 6 x ô Ç y t 7 £ x; ¤ l (charge sensitive ampli- fier) H HAMAMATSU r _ H4083 model` ¦ 6 x % i
. MCA H Canberra _ Series 35-plus ] j¾ ¡ §` ¦ 6 x
%
i Ü ¼ 9 y " é ¶ É r
22Na,
137Cs,
60Co Ü ¼ Ð % ò ² D G _ Amer- sham r _ ] j¾ ¡ § s 9 6 x r y y §& ñ # ¸ % i
.
III. + s ÇÊ Ý õ m Í w ² o
é
ß & ñ $ í © r 621 ± 1
◦C \ ¦ Ä »t % i Ü ¼ 9 $ í © 5 Å q ¸
H ∼ 1 /h s % i . s $ í © © u \ ¦ s 6 x # % 3 É r
&
ñ ` ¦ / B N ¦ ³ ð ` ¦ # f â 10 , U ´s 10 ß
¼l _ CsI (Tl) é ß & ñ ` ¦ % 3 % 3 . é ß & ñ _ & ñ © I \ ¦
· ú
Ðl 0 A # X r] X Û ¼& 7 à Ô! 3 ` ¦ 8 £ ¤& ñ % i . 8 £ ¤
&
ñ õ \ ¦ A _ Bragg ¸| ` ¦ s 6 x # ì r$ 3 % i .
2d sin θ = nλ, n = integer (1) X _ © H 1.5406 ˚ A s ¦ θ _ ° ú כs 38.33
◦, 44.54
◦, 64.85
◦ / B M \ " f x s ß ¼ z ¤ .s [ þ t \ @ /ô Ç Bragg¨ î _ d° ú כ` ¦ > í ß ô Ç õ y y 1.242, 1.098, 0.851 Ü ¼ Ð s H é ß í H{ 9 ~ ½ Ó (simple cubic) & ñ ½ ¨ ¸_ (321) , (411) , (521) _ d° ú כ Ð 0.02 ë ß p um s 1
l x (shift) ) a ° ú כÜ ¼ Ð ì r$ 3 õ é ß í H{ 9 ~ ½ Ó (simple cubic)_
½
¨ ¸\ ¦ t ¦ e H é ß & ñ © I כ Ü ¼ Ð S X ÷ &% 3 .
]
j ) a Ø ¦ l [ þ t \ @ /ô Ç \ -t §& ñ s Fig. 3\
e . 0.511 MeV Â Ò' 1.332 MeV t _ \ -t
% ò
% i \ " f \ -t -G V , ç ß _ + þ A$ í s s % ò % i \ " f y
` ¦ 8 £ ¤& ñ l \ 0 p x < Ê` ¦ Ð# Å Ò ¦ e .
$ í
© r é ß & ñ ` ¦ bialkali F g 7 £ x C ' a, multialkali F
g 7 £ x C ' a Õ ªo ¦ F g s ¸× ¼\ y y [ O u # Ø ¦ l
\ ¦ ] j ô Ç Ê ê y y
22Na,
137Cs,
60Co, _ y \ - t
\ @ /ô Ç \ -t ì r K 0 p x ° ú כ` ¦ 8 £ ¤& ñ ô Ç õ H Table. 1 õ
° ú .
Bialkali F g 7 £ x C ' a` ¦ s 6 x # ] j ) a CsI (Tl) Ø
¦ l _ â Ä º
137Cs _ 0.662 MeV_ \ -t \ @ /K 8.5
% _ \ -t ì r K 0 p x` ¦ % 3 % 3 . ¢ ¸ô Ç
22Na _ Ô æ õ \ " f ª
èY > Ð # Ò q tl H 0.511 MeV _ \ -t \ @ /
#
9.2 %_ \ -t ì r K 0 p x` ¦ % 3 % 3 Ü ¼ ,
22Na _ ¿ 1 ÏÙ þ \ " f
~
½ ÓØ ¦ H 1.275 MeV _ \ -t \ @ /K " f H > Ã ºÖ ¦ s - Á
º ì r K 0 p x ° ú כ` ¦ ½ ¨½ + É Ã º \ O % 3 .
60Co _ 1.173 MeV ü
< 1.332 MeV_ \ -t \ @ /K " f H 7.2 %, 5.5 % _ \
-t ì r K 0 p x` ¦ y y % 3 % 3 .
Multialkali F g 7 £ x C ' a` ¦ s 6 x ô Ç Ø ¦ l \ " f H 0.662 MeV _ \ -t \ @ /K 7.7 %_ \ -t ì r K 0 p x` ¦
% 3
% 3 . ¢ ¸ô Ç _ 0.511 MeV \ -t \ " f H 8.9 % _ \
-t ì r K 0 p x` ¦ % 3 % 3 Ü ¼ 9, 1.274 MeV \ -t _ \ -t ì r K
0 p x É r % i r > Ã ºÖ ¦ s ì r K 0 p x ° ú כ` ¦ ½ ¨ t 3 l wÙ þ ¡ .
1.173 MeV ü < 1.332 MeV_ \ -t H y y 6.6 %ü < 5.1
% _ \ -t ì r K 0 p x` ¦ y y % 3 % 3 .
F
g s ¸× ¼\ ¦ s 6 x K ] j ô Ç CsI (Tl) Ø ¦ l _ â Ä º
137
Cs _ 0.662 MeV_ \ -t \ @ /K 7.5 %_ \ -t ì r K
0 p x` ¦ % 3 % 3 . ¢ ¸ô Ç
22Na _ 0.511 MeV \ -t \ " f H 8.7 % _ \ -t ì r K 0 p x` ¦ % 3 % 3 Ü ¼ 9, 1.274 MeV \ -t \
@
/K " f H 4.9 %_ \ -t ì r K 0 p x` ¦ % 3 ` ¦ Ã º e % 3 .
6
0Co \ 1.173 MeVü < 1.332 MeV_ \ -t H y y 6.2
% ü < 4.8 %_ \ -t ì r K 0 p x` ¦ y y % 3 % 3 . CsI (Tl)$ 3 F g
^
é ß & ñ õ F g s ¸× ¼\ ¦ s 6 x ô Ç Ø ¦ l _ â Ä º_ y
\ -t Û ¼& 7 à Ô! 3 ` ¦ Fig. 4 \ Ð% i .
y
\ -t \ @ /ô Ç CsI (Tl) Ø ¦ l [ þ t _ \ -t ì r K
0 p x _ Õ ªA á Ô Fig. 5\ " f ^ ¦ Ã º e 1 p w s z ´o B H F g s ¸
×
¼\ ¦ 6 x Ù þ ¡` ¦ M : © Ä ºÃ ºô Ç \ -t ì r K 0 p x` ¦ % 3 ` ¦ Ã
º e % 3 Ü ¼ 9 Õ ª 6 £ § É r multialkali F g 7 £ x C ' a, Õ ªo ¦ bialkaliF g 7 £ x C ' a` ¦ 6 xÙ þ ¡` ¦ â Ä º_ í H " f Ð z ¤
.
s
Qô Ç õ H Fig. 6 \ è ß $ 3 F g ^ [ þ t _ F g ´ n uÖ ¦ (light yield) õ F g 7 £ x C ' a[ þ t _ F g y ¸ (photosensitiv- ity) _ : £ ¤$ í ` ¦ : x K ì r$ 3 | ¨ c à º e . { 9 & ñ ô Ç : r ¸_ ¸|
\
" f ^ ¦ M : CsI (Tl)$ 3 F g ^ _ ~ ½ ÓØ ¦y n C{ (emission spec-
trum) H 420 ∼ 800 nm \ ` 5 g e Ü ¼ 9 þ j@ /~ ½ ÓØ ¦ © É r
540 nm s ¦ F g ´ n uÖ ¦ É r 65,000 photons/MeV s . s
\
@ /K " f bialkali F g 7 £ x C ' a _ F g y ¸ H 300 ∼ 700 nm % ò % i \ ( 4 Re Ü ¼ 9 350 nm\ " f þ j@ / F g y ¸\ ¦ ° ú
H . ô Ǽ # multialkali F g 7 £ x C ' a _ â Ä º H F g y ¸ H 300 ∼ 900 nm \ ( 4 Re Ü ¼ 9 420 nm\ " f þ j@ /_ F g y ¸
\
¦ ° ú H כ ` ¦ ^ ¦ Ã º e . " f bialkali F g 7 £ x C ' a
Ð H multialkali F g 7 £ x C ' a s 8 ´ ú § É r CsI (Tl) $ 3 F
g ^ \ " f µ 1 ÏÒ q t H F g [ þ t` ¦ F g Ð Ë ¨# QÅ Ò 9 s H
² D G Ø ¦ l _ \ -t ì r K 0 p x _ ¾ Ó © ` ¦ 4 R ¸> ) a כ Ü
¼ Ð K $ 3 ) a .
¢
¸ô Ç F g s ¸× ¼_ â Ä º F g y ¸ H 320 ∼ 1060 nm% ò
%
i \ 5 g" f ( 4 Re Ü ¼ 9 © s 7 £ x < Ê\ + þ A& h Ü
¼ Ð 7 £ x H : £ ¤$ í ` ¦ ° ú H כ ` ¦ ^ ¦ Ã º e . " f CsI (Tl)$ 3 F g ^ _ þ j@ / ~ ½ ÓØ ¦ © \ " f F g y ¸ multialkali F
g 7 £ x C ' a Ð 8¹ ¡ ¤ ß ¼l M :ë H \ É r # Q " F g 7
£
x C ' a Ð ¸ Ä ºÃ ºô Ç \ -t ì r K 0 p x` ¦ t H כ Ü ¼ Ð
«
Ñ ) a . í H Ã º CsI & ñ \ thallium (Tl)` ¦ Ö ¸$ í ] j Ð Å Ò{ 9 Ù þ
¡` ¦ â Ä º CsI (Tl) & ñ _ þ j@ / ~ ½ ÓØ ¦ © õ F g ´ n uÖ ¦ s ß
¼> 7 £ x ÷ &% 3 6 £ §` ¦ · ú Ã º e .
s
ü < ° ú s $ 3 F g Ø ¦ l _ \ -t ì r K 0 p x É r $ 3 F g ^ _ ~ ½ Ó Ø
¦y n C{ (emission spectrum) F g 7 £ x C ' a ¢ ¸ H F g
Fig. 3. Energy calibration curve of detectors.
Fig. 4. Gamma-ray energy spectrum of CsI (Tl) photo- diode detector.
s
¸× ¼_ F g y ¸ (photosensitivity)ü < þ j@ / ~ ½ ÓØ ¦ © % ò
%
i \ " f \ O ¸ ú { 9 u H \ _ > r ô Ç .
` O
Û ¼\ l # H F g _ Ã º 7 £ x Ø ¦ l _ ì rF g :
£ ¤$ í É r ¾ Ó © ÷ &l M :ë H \ $ 3 F g ^ \ & h ] X ô Ç Ö ¸$ í ] j\ ¦ : x K
F g ´ n uÖ ¦ _ 7 £ x r v ¦, $ 3 F g ^ _ þ j@ /~ ½ ÓØ ¦ © õ F
g 7 £ x C ' a _ þ j ¦ F g y ¸ % ò % i ` ¦ { 9 u r v H כ s $ 3 F g
Ø ¦ l ] j \ " f H B Ä º × æ כ ¹ . s Qô Ç o\ ¦ ¸ ú s 6
x & h ] X ô Ç F g 7 £ x C ' a _ & ñ ` ¦ : x K Ø ¦ l _ y
ì rF g: £ ¤$ í ` ¦ ¾ Ó © r ~ ´ Ã º e 6 £ §` ¦ · ú Ã º e % 3 .
IV. + s Ç Â ] Ø
CsI (Tl) é ß & ñ ` ¦ z ´+ « >z ´\ " f Bridgmané ß & ñ $ í © Ð
\
¦ s 6 x # $ í © r õ $ 3 F g Ø ¦ l \ & h 6 x s 0 p x
Fig. 5. Energy resolutions of CsI (Tl) detectors as a function of energy.
Fig. 6. The photosensitivity is shown for bialkali PMT,
multialkali PMT and silicon pin photodiode by a dotted
curve. The light yield of CsI and CsI (Tl) crystals is also
shown in arbitrary unit by a solid curve [1,2,3,4].
ô
Ç $ 3 F g ^ é ß & ñ ` ¦ % 3 ` ¦ Ã º e 6 £ §` ¦ S X ½ + É Ã º e % 3 .
¹
¢
¤ î ß Ü ¼ Ð % i ` ¦ M : ¸ È Ò" î $ í s a % ~ ¤Ü ¼ 9 X- r ] X
ì r$ 3 ` ¦ ô Ç õ (411) ` ¦ Å Ò Ü ¼ Ð ¦ (321) õ (521) ` ¦ ° ú ¦ e H é ß í H{ 9 ~ ½ Ó_ & ñ ½ ¨ ¸\ ¦ ° ú ¦ e % 3
. CsI (Tl)é ß & ñ É r ç ß _ ¸K $ í ` ¦ ° ú H X < ³ ð / B N r
\ s Qô Ç $ í | 9 ` ¦ s 6 x ] j\ ¦ 6 x t · ú § ¦
¸ Ó ü t \ ] X É r 7 á x s Ð ~ 1 > ³ ð ` ¦ È Ò" î > % o ½ + É Ã º e
6 £ §` ¦ · ú Ã º e % 3 .
CsI (Tl) é ß & ñ ` ¦ bialkali F g 7 £ x C ' a, multialkali F
g 7 £ x C ' a Õ ªo ¦ F g s ¸× ¼\ ¦ 6 x # Ø ¦ l \ ¦ ]
j # \ -t ì r K 0 p x` ¦ 7 £ ¤& ñ ô Ç õ , F g s ¸× ¼
multialkali F g 7 £ x C ' a s bialkali F g 7 £ x C ' a` ¦
6 x H â Ä º Ð ¸ © \ -t ì r K 0 p x s Ä ºÃ ºô Ç כ Ü
¼ Ð z ¤ .
F
g s ¸× ¼\ ¦ s 6 x # ] j ) a CsI (Tl) Ø ¦ l _ â Ä
º Ø ¦ l _ E Z O 7 £ x; ¤ l 1 p x _ r н ¨$ í \ " f µ 1 ÏÒ q t H ¸ ú 6
£
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Characteristics of CsI (Tl) Scintillation Detectors for Gamma-Ray Spectroscopy
Soo-Il Kwon
∗Department of Physics, Kyonggi University, Suwon 443-760 (Received 13 January 2006)
CsI (Tl) crystals were grown by using a Bridgman growing system, and scintillation detectors were fabricated to measure the spectroscopic characteristics of gamma rays. The size of the crystal was 10 mm in diameter and 10 mm long with a 1000-ppm activator density. After the fabrication of the radiation detector with this single crystal and a bialkali photomultiplier (PMT), a multialkali PMT, or a photodiode, the energy resolutions of CsI (Tl) detectors have been measured using
137Cs,
22
Na, and
60Co gamma rays. For 0.662-MeV
137Cs, the energy resolutions of the CsI (Tl) detectors were 8.5 %, 7.7 %, and 7.5 % with a bialkali PMT, multialkali PMT, and a photodiode, respectirely.
PACS numbers: 29
Keywords: Bridgman growing system, CsI (Tl) scintillation detector, PMTs, Photodiode, Energy resolution
∗
