concept of the scanning table in strasbourg
DESCRIPTION
Concept of the scanning table in Strasbourg. François DIDIERJEAN Tatjana FAUL, Fabrice STEHLIN Strasbourg. AGATA week. 8 - 11 July 2008 Uppsala, Sweden. X-Y scanning table of Strasbourg. detector fixed position - PowerPoint PPT PresentationTRANSCRIPT
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Concept of the scanning table in
Strasbourg
François DIDIERJEAN
Tatjana FAUL, Fabrice STEHLIN
StrasbourgAGATA week. 8 - 11 July 2008
Uppsala, Sweden
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X-Y scanning table of Strasbourg
detector fixed position
radioactive source and collimator X - Y moving
to improve the device to access to the Z information
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Scheme of the scanning table of Liverpool
BGO
Pb collimator
slites 1.5 m
m
Z
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Po
siti
on
sen
siti
ve
scin
till
ato
r d
etec
tor
Objectives : 1. use a unique position sensitive detector
2. increase the number of slites
662
keV
288 keV
to find the minimal distance between 2 slites to disentangle 2 diffused
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electronics
GSO scintillator
5 cm x 5 cm x 2 mm
PM, Hamamatsu
8 x 8 pixels Pb collimator
241Am
Validation tests of the concept
the experimental setup :
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0
10
20
30
40
50
0 5 10 15 20 25
position réelle (mm)
po
siti
on
mes
uré
e (m
m)
Validation test of the GSO-PM block
241Am
Real position (mm)
Mea
sure
d p
osi
tio
n (
mm
)
linear variation except for the last 5 mm saturation due to the border effect
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241Am
Variation of the slite-to-slite distance
2, 3, 4
, 5, 6
mm
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0
5000
10000
15000
20000
25000
30000
35000
0 5 10 15 20 25 30 35 40 45 50
0
5000
10000
15000
20000
25000
30000
35000
40000
0 5 10 15 20 25 30 35 40 45 50
0
5000
10000
15000
20000
25000
30000
0 5 10 15 20 25 30 35 40 45 50
Variation of the slite-to-slite distance
Measured position (mm)
3 mm / 21 % overlapp
4 mm / 12 % overlapp
5 mm / 4 % overlapp
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Proposed scheme of the Strasbourg scanning table
(collimator thickness 4 mm, slites 1.5 mm)
16 slites 1.5 m
m
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GEANT 4 simulations
scintillators
1 cm x 5 cm x 3 mmBGO or LaBr3 or LSO
10000 -rays of 288 keV
to determine the best scintillator detector type
to see the effect of the scattering
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BGO scintillator (1cm)
8195
764
171
174
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GSO scintillator (1cm)
7214
1233
253
297
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LaBr3 scintillator (1cm)
2912
2499
330
282
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LaBr3 scintillator (2 cm)
4378
3396
645
632
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Conclusions.
The Choice of the scintillator should be BGO which presents the smaller spot size composed of Compton scattering interaction points.
To do list :
Geant simulation calculations to determine the optimal dimension of the scintillator (in particular the thickness).
validation test with radioactive source (288 keV rays) to decide the use of
* a large scintillator coupled to segmented PM.
* a set of thin scintillators coupled each one to a PM via optical fibers.