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Tests of scintillators. CsI, CsI(Na), BGO, NaI(Tl). CsI(Tl). CsI(Na). 15 x 15 mm. 9 x 9 mm. 170 mm. Full absorption. CsI(Na) scintillator with 2 PMT readout. Measurement without collimation 137 Cs, 661 keV. Energy of PMT 2 (big window). Energy of PMT 1 (small window). Ratio (position). - PowerPoint PPT Presentation
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Tests of scintillators
CsI, CsI(Na), BGO, NaI(Tl)
CsI(Tl)
CsI(Na)
170 mm
15 x 15 mm9 x 9 mm
Energy of PMT 1 (small window)
Ene
rgy
of P
MT
2 (
big
win
dow
)
CsI(Na) scintillator with 2 PMT readout
Full absorption
Measurement without collimation 137Cs, 661 keV
Energy of PMT 1 (small window)
Ene
rgy
of P
MT
2 (
big
win
dow
)
CsI(Na) measured with a collimated source
Sum (e
nerg
y)
Ratio (position)
Energy spectrum (sum of 2 PMT’s energies)
Sum of 2 PMTs energies
Energy resolution 9.6% at 661 keVConstant for the position of the interaction
Position resolution (ratio of the PMT’s energies)
Light division between 2 PMTs
15 cm
10 cm
5 cm
Position resolution
0 2 4 6 8 10 12 14 160.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1 Y =0.29835-0.00312 X+0.0029 X2
light
div
isio
n be
twee
n P
MT
s
position in scintillator, cm
Position resolution
0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.00
2
4
6
8
10
12
14
16
18po
sitio
n in
sci
ntill
ator
, cm
light division between PMTs
Position resolution 1.5 – 3 cm
0.0 0.2 0.4 0.6 0.8 1.00
1
2
3
4
5ab
sorp
tion
dist
ance
, cm
energy, MeV
CsI
Ge
Mean absorption distance
Readout with one PMT
1000 1500 2000 2500 3000 3500 4000 4500 50000
100
200
300
400
coun
ts
energy of one PMT
5 cm
10 cm15 cm
CsI, pure
Energy resolution
Resolution 17 – 19 %
Sum energy
Position resolution
Light division between 2 PMTs
15 cm
10 cm
5 cm
Position resolution
2 4 6 8 10 12 14 16 180.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0 Y =0.32407+0.16521 Xlig
ht d
ivis
ion
betw
een
PM
Ts
position, cm
Position resolution
0.5 1.0 1.5 2.0 2.5 3.0 3.5
2
4
6
8
10
12
14
16
18
20
posi
tion,
cm
light division between PMTs
Position resolution 2 – 8 cm
BGO
Energy of PMT 1 (small window)
Ene
rgy
of P
MT
2 (
big
win
dow
)
BGO scintillator with 2 PMT readoutScintillator was illuminated by Cs137 source (661 keV) without a collimator
Strong nonuniformity of light yieldalong the crystal distance
BGO collimated measurement
Full absorption
BGO collimated measurement
Full absorption
1)Light yield is strongly non uniform along the crystal distance
2)Light separates always in the same proportion between left and right sides
3)Energy resolution ≈18% (big window) ÷ 24% (small window)
BGO results
CsI(Tl)
7% at 661 keV
2.5 cm2.5 cm
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