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JAEA
-Research
JAEA-Research
2008-115
− J-PARC/MLF 生命物質構造解析装置「iBIX」のためのコンパクト型検出器の開発 −
波長シフトファイバを用いた高検出効率、高位置分解能型2次元シンチレータ中性子検出器の
開発研究
中村 龍也 片桐 政樹 細谷 孝明* 美留町 厚海老根 守澄 曽山 和彦 Erik Schooneveld* Nigel Rhodes*
Tatsuya NAKAMURA, Masaki KATAGIRI, Takaaki HOSOYA*, Atsushi BIRUMACHI*Masumi EBINE, Kazuhiko SOYAMA, Erik Schooneveld* and Nigel Rhodes*
J-PARC センター
J-PARC Center
March 2009
Japan Atomic Energy Agency 日本原子力研究開発機構
JAEA
-Research 2008-115
波長シフトファイバを用いた高検出効率、高位置分解能型2次元シンチレータ中性子検出器の開発研究 ─ J-PARC/M
LF
生命物質構造解析装置「iBIX
」のためのコンパクト型検出器の開発
─
日本原子力研究開発機構
Development of Two-dimensional Scintillator Neutron Detector
using Wavelength-shifting Fibres
- Development of a Compact Detector for iBIX Instrument in J-PARC/MLF -
1
JAEA-Research 2008-115
2
- J-PARC/MLF iBIX -
J-PARC
*1 + +
Erik Schooneveld*2 Nigel Rhodes*2
(2008 12 19 )
J-PARC/MLF
2
13.3 x 13.3 cm2 69
ISIS 2
------------------------------------------------------------------------------------------------------------------------
J-PARC 319-1195 2-4+
*1
*2 Rutherford Appleton Laboratory, ISIS facility
��
JAEA-Research 2008-115
2
JAEA-Research 2008-115
Development of Two-dimensional Scintillator Neutron Detector
using Wavelength-shifting Fibres
- Development of a Compact Detector for iBIX Instrument in J-PARC/MLF -
Tatsuya NAKAMURA, Masaki KATAGIRI, Takaaki HOSOYA*1, Atsushi BIRUMACHI+,
Masumi EBINE+, Kazuhiko SOYAMA, Erik Schooneveld*2, and Nigel Rhodes*2
Materials and Life Science Division, J-PARC Center,
Japan Atomic Energy Agency
Tokai-mura, Naka-gun, Ibaraki-ken
(Received December 19, 2008)
A compact two-dimensional neutron detector was developed for iBIX instrument in the
J-PARC/MLF. The specifications required for the detector were a spatial resolution of less
than 1 mm, a detector efficiency of more than 50% for thermal neutrons, a gamma sensitivity
of less than 10-6, detector coverage of around 16 x 16 cm2 with least dead area,
compactness, modularity, and a pulse pair resolution of less than 2 s. The detector
components including new scintillator material, wavelength-shifting fibres, photomultipliers,
amplifier/discriminator electronics, signal processing electronics, time of flight data
acquisition module, were studied in detail and optimized for the purpose. The compact
prototype detector that has a neutron sensitive area of 13.3 x 13.3 cm2 was made and
feasibility of the detector was demonstrated successfully in the experiments at the ISIS
pulsed neutron source.
Keywords: Neutron Detector, Scintillator, Two-dimensional Detector, Wavelength-shifting
Fibre
------------------------------------------------------------------------------------------------------------------------ + Engineering Services Department, Nuclear Science Research Centre, Tokai Research and
Development Center *1 Ibaraki University, Department of Biomolecular Functional Engineering *2 Rutherford Appleton Laboratory, ISIS facility
����
JAEA-Research 2008-115
JAEA-Research 2008-115
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3
1. 1
2. WLSF 2 1
2.1 1
2.2 2
2.3 3
3. 4
3.1 ZnS/10B2O3 4
3.2 6
3.3 8
3.4 / 10
3.5 11
3.6 ToF 12
4. 12
5. ISIS 12
5.1 13
5.2 ToF 13
5.3 13
6. 14
14
14
����
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4
Contents
1. Introduction 1
2. Two-dimensional WLSF-type scintillator neutron detector 1
2.1 Principle of neutron detection 1
2.2 Detector specifications required for iBIX instrument 2
2.3 Detector design 3
3. Development of detector components for a iBIX detector 4
3.1 ZnS/10B2O3 scintillator 4
3.2 Evaluation of a wavelength-shifting fibre 6
3.3 Multianode photomultiplier 8
3.4 Amplifier/discriminator circuit module for photon counting method 10
3.5 Digital signal processing and encoding electronics 11
3.6 Time of flight data acquisition circuit module 12
4. A prototype 2-d detector system 12
5. Detector performance test at ISIS pulsed neutron source 12
5.1 Spatial resolution 13
5.2 Time of flight measurements 13
5.3 Neutron diffraction measurements 13
6. Conclusion 14
Acknowledgements 14
References 14
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1.
2008 5 J-PARC/ (Materials and Life science Facility,
MLF)
JRR3 2
ISIS
MLF 23
1)
2 2
(> 50%@1A) (< 1 mm) (> 16 x 16 cm2)
(> 70%) (< 2 s) ToF
1 100
50
2
10 15
(Wavelength-shifting fibre, WLSF)
WLSF
2
16 19
20
2. WLSF 2
2.1WLSF 1996
D.P. Hutchingson2)
3,4,5)
WLSF
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6) WLSF
WLSF
7) 8) 9)
1 ZnS/6LiF WLSFZnS/6LiF 6Li(n, )T
ZnS (4.78 MeV)( 450 nm)
WLSF WLSF
(Photomultiplier, PMT)2 2
X Y 256 WLSFWLSF 90
PMT ( )/ /
2.2
1) (> 50% for thermal neutrons)
2) (< 1 mm )
3) (< 10-7)
4) (> 160 mm x 160 mm)
5) (< 30%)
6)
7) (< 2 s)
8) Time of Flight (ToF)
1 x 1 x 1 mm3
10-100 Å
( MeV
)
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1 mm
1
ToF
2 s
WLSF 2 1 mm
ISIS SXD 35%(1.8 Å )10)
40.7%11)
50%
ISIS 10-6
12) ( )
10-6
20~30%
PMT
2
WLSF 2
2.3WLSF
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2
1) 6Li 10B ZnS
2) WLSF 1 ZnS/10B2O3
WLSF
3) WLSF 90WLSF 90
PMT WLSF
WLSF
4)
/ PMT
5)
Field Programmable Gate Array (FPGA)
3.
3.1 ZnS/10B2O3
6LiF6Li 4 10B
6Li 10B6Li + n 3H + + 4.78 MeV, 940 barn for thermal neutrons, 10B + n 7Li*+ + 2.792 MeV, (6%)
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7Li*+ + 2.31 MeV, (94%) 3840 barn for thermal neutrons, 10B Q
(1)10B 6Li
7Li 4.2 m 2.3 m13) 6LiF 6.1 m 33.0 m
13) ZnS
Q 4.78 MeV10B
10B2O314) ZnS
ZnS:Ag H310BO3 1
600 ZnS H310BO31.5 : 1 JAEA ZnS/10B2O3 1
JAEA (50 x 50 mm2)
ZnS/10B2O3 ZnS
PMT15) PMT
3 Am-Be ISIS ZnS/6LiF16) (AST 0.4 mm) ZnS/10B2O3
ZnS/10B2O3ZnS/10B2O3 0.3 mm ISIS ZnS/6LiF
0.1 mm
ZnS/10B2O3 ISIS ZnS/6LiF
ZnS/10B2O3 6Li
ISIS ZnS/6LiF
ZnS/10B2O3 ISIS ZnS/6LiF
ZnS/10B2O3
0.17 ~ 0.5 mm ZnS/10B2O32 140 mm x 140 mm ZnS/10B2O3 17)
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(2)J-PARC (BL03)
0.5~8 Å
( )
ZnS/10B2O3 0.2 mm 0.3 mm 2
WLSF (64 X 64
) 4 Am-Be
JAEA ZnS/10B2O3 0.3 mm
0.2 mm 20~30%
ISIS 1~5 Å
0.2 mm
WLSF
0.4 mm
3.2(1)
WLSF PMT
WLSF
10 1 2
100 ppm
4
3.4~7% /
WLSF ZnS /WLSF WLSF /PMT
5
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BCF-91A (a)
Y11 (c) ZnS (450 nm) BCF-92 (b)
BCF-92 Y11 BCF-92 ZnS18) Y11 (BCF91A) BCF- 92
( )
0.5 mm
(2) WLSF 1
WLSF
WLSF
Y11 ( 0.5 mm)
50 160 ppm 6
100~160 ppm
100~160 ppm
WLSF 160 ppm
(3)7 WLS 90
0.5 mm Y11 5~1000 mm LED
8
20 mm
10 mm 5 mm
80%
Y11 WLSF 90 1
9 11
90 73
10
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30%
3.3512 PMT PMT 1 mm
1 30 mm x 30 mm x 45 mm( )
64 PMT PMT(H7546) 8
PMT 107 16
PMT(H8711) 19) 32
3 H8711 H7546 H7546 1
2 x 2 mm2 20 PMT
1 mm 1.5%20) PMT
107 PMT
(1) PMTH7546 PMT -950 V 2 x 106 20)
PMT
12 3
12 2.4 : 2.4 : 2.4 : 1 : 1 : : 1 : 1.2
PMT PMT
ZnS 10
1 WLSF (64 ) H7546
H8711( ) H7546
H8711 H7546 H8711
PMT
PMT
H7546 PMT
(2) (UBA) PMT2007 10
PMT(Ultra
Bialkali photomultiplier, UBA-PMT) 11 21)
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WLSF 500 nm 16% 20% 1.3
UBA-PMT 2
(3)UBA H8711MOD(16
PMT) UBA
H8711MOD
4 x 4 mm2 H7546 4 2
mm WLSF 11 H7546 (20%) 11
WLSF WLSF LED
12 PMT 6
UBA BA-PMT 1.3~3.1%
0.1% %
PMT
UBA-PMT BA-PMT 1.2~1.8
PMT 3% BA-PMT
UBA-PMT
(4)UBA-PMT BA-PMT BA
UBA-PMT 2 -800 V 0.03 0.07
nA 1.4 4.8 nA UBA-PMT BA-PMT
UBA-PMT
PMT
X,Y
UBA-PMT PMT
13 1 WLSF (64 ) PMT BA-PMT
UBA-PMT
UBA-PMT BA-PMT
2 PMT (
) 104 cps/cm2
13 x 13 cm2 10-2 cps
2 UBA-PMT
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(5)UBA BA-PMT 14
UBA-PMT BA-PMT 1.3
PMT
3.4 /PMT 1
PMT
mV ns 1
512
/
/
(1)16
PMT ( >100MHz)
10~40 WLSF 1 64
PMT(H7546) 252Cf
15 40
60 ( 600 MHz)
32 / ( 4 )
IC(THS3201 LMH6703) 2
/
16 40 mV
PMT -950V
(2) 32 /
(512 )
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IC
AD8001
220 MHz 4 32 /
7 (5 W/ 1 80 W/16 )
100 mm X 160 mm 17 /
30 mV
16 /
16 / 5
3.5
ToF
X Y 256 Low Voltage Differential Signaling (LVDS)
FPGA
FPGA 100 MHz 5 ns PMT
1 FPGA
1~4
ZnS
( )
( 18) X Y
PMT
2 FPGA
ToF
LVDS 19
1 X Y 8 ToF 12
DAQ ( 100 )
DAQ
6 30 cm x
15 cm x 25 cm ( )
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3.6 ToFToF ToF
ToF J-PARC T0
ToF 7 VME
1 1 FPGA 2GB (1GB X2) DRAM 16 MB SDRAM
FPGA
256 ch X 256 ch 4096
26 bit
T0 VME
4.
WLSF 2
820 2 1 m
J-PARC/MLF
2
30
177 cm2 13.3 cm X 13.3 cm
1 mm
69
: 10-6 (60Co )
16 cm X 16 cm X 30 cm
5 kg
5. ISIS
WLSF 2
ISIS
2
ROTAX 22) 15.74 m
0.6~5.2 Å 106
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n/s/cm2
5.11 mm Cd
PMT-850 / 40 mV
1 21 (a)
ToF (b) 1( 1 s ) (a)
21 (b)
2 mm 1 mm
5.2 ToFToF
ToF 21(a) ToF 22
1 1.5 2 4 s
ToF ( 2 s23))
ISIS 1.5~1.8 Å ToF
5.32 Ni ( 6
mm) 9 ROTAX 2
2 90 (detector 1) 45 (detector 2)
65, 140 mm 23 ToF
1
24 ToF 2 ToF( )
Ni ToF
25
ToF
Ni ToF 2
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6.
J-PARC/MLF 2
2
ISIS
2
JRR-3 CHOP
J-PARC
1) J-PARC/MLF BL03: < http://j-parc.jp/MatLife/ja/instrumentation/bl03/bl03.html>
2) D.P. Hutchinson, et al., Proc. SPIE 3769 (1999) p.88.
3) A. Gorin, et al., Nucl. Instrum. and Meth. A 479 (2002) p.456.
4) K. Sakai, et al., Nucl. Instrum. and Meth. A 529 (2004) p.301.
5) M. Katagiri et al., Nucl. Instrum. and Meth. A 529 (2004) p.325.
6) for example, SAINT-GOBAIN, Optical Scintillating Fibers catalogue.
7) A. Menzione, Proc. 2nd Int. Conf. on Calorimetry in High Energy Physics, Capri, 1991
(World Scientific, Singapore, 1992) p.131.
8) ATLAS TileCal, E. Mazzoni, Nucl. Instrum. and Meth. A 409 (1998) p.601.
9) K. Kuroda, et al., Nucl. Instrum. and Meth. A 430 (1999) p.311.
10) N.J.Rhodes, et al., Nucl. Instrum. and Meth. A 392 (1997) p.315.
11) M. Katagiri, et al., Nucl. Instrum. and Meth. A 529 (2004) p.274.
12) N.J.Rhodes, Private communication
13) Calculation with SRIM code, < http://www.srim.org/ >
14) T. Kojima et al., Nucl. Instrum. and Meth. A 529 (2004) p.325.
JAEA-Research 2008-115
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15) T. Nakamura et al., IEEE NSS 2008, to be published in Conference Record.
16) Applied Scintillation Technologies : < http://www.appscintech.com/>
17) N. Tsutsui, presented at 1st International Symposium on Pulsed Neutron and Muon
Sciences (IPS08), Mito, Ibaraki, Japan, 5 – 7 March 2008
18) M. Katagiri , Japanese Patent pending
19) Hamamatsu photonics, Multianode photomultiplier tube assembly H8711 catalogue, P2.
20) Hamamatsu photonics, Multianode photomultiplier tube assembly H7546 catalogue, P2.
21) Hamamatsu photonics, Ultra Bialkali photomultiplier catalogue, P11.
22) ISIS ROTAX < http://www.isis.rl.ac.uk/excitations/rotax/ >
23) T. Hosoya, et al., presented at 1st International Symposium on Pulsed Neutron and
Muon Sciences (IPS08), Mito, Ibaraki, Japan, 5 – 7 March 2008, to be published in NIMA.
JAEA-Research 2008-115
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Fig. 1: A schematic view of a typical neutron detector using a ZnS/6LiF scintillator and wavelength-shifting fibres.
Fig. 2: A schematic view of a two-dimensional neutron detector system using a neutron-sensitive scintillator and wavelength-shifting fibres. This system comprised of 256 fibres in both axis.
NeutronsZnS/6LiFscintillator
WLSF
Scintillation light
Reemitted light
NeutronsZnS/6LiFscintillator
WLSF
Scintillation light
Reemitted light
WLS fibers for Y axis
ZnS-type ScintillatorNeutrons
64 ch PMT x 4
Photon counting signal for Y axis
Scintillator
32 ch amp./discri. x 8
WLS fibers for X axis
Photon counting signal for X axis
64 ch PMT x 4
32 ch amp./discri. x 8
Image signal processing module
WLS fibers for Y axis
ZnS-type ScintillatorNeutrons
64 ch PMT x 4
Photon counting signal for Y axis
ScintillatorScintillator
32 ch amp./discri. x 8
WLS fibers for X axis
Photon counting signal for X axis
64 ch PMT x 4
32 ch amp./discri. x 8
Image signal processing module
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Photo 1: A ZnS:Ag/10B2O3 scintillator made in house (50 mm x 50 mm).
Fig. 3: Pulse height spectra of a developed ZnS:Ag/10B2O3 and a standard ZnS/6LiF scintillator manufactured by AST Co. The scintillators were installed in an ENGIN-X type light reflector grid to collect scintillation light efficiently from the both sides of the scintillator15).
0
200
400
600
800
1000
0 50 100 150 200
Pulse height, ch
Cou
nts
/ 500
s
.
ZnS/LiF
ZnS/B_2O_3
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Photo 2: Large size ZnS:Ag/10B2O3 scintillators manufactured by Chichibufuji Co. The size of the scintillators measured 14 cm x 14 cm. The thickness of the scintillator was 0.175 mm (left) and 0.375 mm (right).
Fig. 4: Neutron counts measured with a 2-d test detector equipped with a 0.2 or 0.3 mm-thick ZnS/10B2O3 scintillator.
0
100
200
50 70 90 110 130 150 170Threshold voltage, mV
Neu
tron
coun
ts in
cps
0.2 mm0.3 mm
Scintillator area : 32 x 32 mm2
ZnS/10B2O3 scintillator
Scintillator thickness
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(b) BCF-92
0.0
0.2
0.4
0.6
0.8
1.0
1.2
300 400 500 600 700Wavelength, Å
Rel
ativ
e in
tens
ity, a
.u.
. Absorption
Emission
ZnS scintillation light
PMTsensitivity
Fig. 5: Light absorption/reemission spectra of a ZnS/6LiF scintillator, WLSF and a photocathode sensitivities of a bialkali PMT.
(a) BCF-91A
0.0
0.2
0.4
0.6
0.8
1.0
1.2
300 400 500 600 700Wavelength, Å
Rel
ativ
e in
tens
ity, a
.u.
. Absorption
Emission
ZnS scintillation light
PMTsensitivity
(c) Y11
0.0
0.2
0.4
0.6
0.8
1.0
1.2
300 400 500 600 700Wavelength, Å
Rel
ativ
e in
tens
ity, a
.u.
.
Absorption
Emission
ZnS scintillation light
PMTsensitivity
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Fig.6: Light output of a Y11 WLSF of front and back fibres in a 2-d detector as a function of dye content. The Y11 fibres had square-shape with a side length of 0.5 mm.
Fig. 7: A schematic view of a scintillator/fibre head in a 2-d detector.
Wavelength shift ing fibe rsfor Y-axis readout
64 ch Multi-anodePhotomultiplier
Wave length shifting fibe rsfor X-axis readout
Fiber part bent in 90 degree
ZnS:Ag/ B2O3scintillator sheet
Neutrons ZnS:Ag/ B2O3scintillator sheet
Wavelength shift ing fibe rsfor Y-axis readoutWavelength shift ing fibe rsfor Y-axis readout
64 ch Multi-anodePhotomultiplier64 ch Multi-anodePhotomultiplier
Wave length shifting fibe rsfor X-axis readoutWave length shifting fibe rsfor X-axis readout
Fiber part bent in 90 degreeFiber part bent in 90 degree
ZnS:Ag/ B2O3scintillator sheetZnS:Ag/ B2O3scintillator sheet
NeutronsNeutrons ZnS:Ag/ B2O3scintillator sheetZnS:Ag/ B2O3scintillator sheet
0
0.2
0.4
0.6
0.8
0 100 200 300 400
Dye content in a 1/2-mm square fibre, ppm
Ligh
t out
put (
a.u.
)
I_f, simulationI_b, simulationexp. dataexp. dataexp. dataexp. data
Y11, Kuraray1/2-mm square fibres
front fibres
back fibres
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Fig. 8: Light transmission of round-shaped Y11 fibres as a function of bending radius. A diameter of a fibre was 0.5 mm. Four of Y11 fibres with multiclad were tested.
Fig. 9: Light transmission of square-shaped Y11 fibres with 90-degree bending.
0
1
2
3
4
5
6
0.62 0.66 0.7 0.74 0.78
Sam
ples
Transmissivity
0.6
0.7
0.8
0.9
1.0
1.1
0 5 10 15 20 25 30
Bending radius, mm
Nor
mal
ized
ligh
t out
put
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Photo 3: Multianode photomultipliers, H8711 (16 ch.) and H7546 (64 ch.), manufactured by Hamamatsu Co.
Fig. 10: Neutron counts measured with a 1-d WLSF test detector equipped with a H8711 or H7546 PMTs.
H8711
H7546
H8711
H7546
0
100
200
300
400
500
600
800 850 900 950 1000 1050High voltage, V
Neu
tron
cou
nts,
cps
H7546 with modified resistive chain
H8711 (16 ch, standard)
PMT
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Fig. 11: A quantum efficiency of an ultra bialkali PMT manufactured by Hamamatsu Co21).
Fig. 12: Light cross talk between pixels on a PMT window in a bialkali (BA) PMT (a) and ultra bialkali (UBA) PMT (b). The light cross talk was defined as a ratio of a signal height relative to a signal in a center pixel (light incident pixel).
0.12.00.2
1.41001.3
0.42.20.3
0.12.00.2
1.41001.3
0.42.20.3
0.12.40.4
2.61001.4
0.33.10.4
0.12.40.4
2.61001.4
0.33.10.4
(a) BA-PM T (b) UBA-PM T
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Fig. 13: Background counts measured with a 1-d WLSF test detector with a BA or UBA PMT.
Fig. 14: Neutron counts measured with a 2-d WLSF test detector with a BA or UBA PMT.
1.E-05
1.E-04
1.E-03
50 100 150 200 250
Threshold voltage, mV
Back
grou
nd c
ount
s (1
/s/c
m^2
)
BA-PMTUBA-PMT
0
50
100
150
200
250
0 50 100 150 200
Threshold voltage, mV
Neu
tron
coun
ts, c
ps
UBA-PMT
BA-PMT
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Fig. 15: Neutron counts measured with a 2-d WLSF test detector with a preliminary amplifier board. The gain of the amplifier was variable from 10 to 40.
Photo 4: 32 channel amplifier/discriminator boards. A test board (left) and a prototype board (right).
0
1
2
3
4
5
6
7
8
0 10 20 30 40 50 60 70 80
x10 no14
x20 no20
x30 no15
x40 no11
Cou
ntin
g ra
te, c
ps
Discrimination level, mV
18 cm 16 cm
12 c
m 10 cm
18 cm 16 cm
12 c
m 10 cm
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Fig. 16: Neutron counts measured with a 2-d WLSF test detector equipped with a 32-channel test amplifier/discriminator board.
Fig. 17: Pulse height spectrum of photons measured a prototype 32-channel amplifier/discriminator board.
0
20
40
60
80
100
0 0.1 0.2
Cou
nts
Peak voltage, V
AD8001Gain : x100
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Photo 5: A prototype mini power crate for amplifier/discriminator boards.
Fig. 18: A pattern matching method employed in a signal processing and encoder module to determine a position of an incident neutron.
(a) F ront view (b) Rear view
20 cm
18cm
15 cm
(a) F ront view (b) Rear view
20 cm
18cm
15 cm
(b) Rear view
20 cm
18cm
15 cm
Finding position
One
Two
Three
Four
A number oflit fibres
Determined position
Two of three
Three of four
Three of four
A number oflit fibres
Determined position
Finding position
One
Two
Three
Four
A number oflit fibres
Determined position
One
Two
Three
Four
A number oflit fibres
Determined position
Two of three
Three of four
Three of four
A number oflit fibres
Determined position
Two of three
Three of four
Three of four
A number oflit fibres
Determined position
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Photo 6: A signal processing and encoder circuit module.
Fig. 19: A data flow and data bit structure of the signal processing and encoder module.
Condition Parallel dataoutput
Analysisstatus
4bit4bitline
To Data readout module
Condition Parallel dataoutput
Analysisstatus
4bit4bitline
To Data readout module
LVDS output connector(To TOF data acquisition module)
(a) F ront view (b) Rear view
30 cm
16 LVDS input connectors(From Amp. & discriminator)
25cm
15cm
LVDS output connector(To TOF data acquisition module)LVDS output connector(To TOF data acquisition module)
(a) F ront view (b) Rear view
30 cm
16 LVDS input connectors(From Amp. & discriminator)
25cm
15cm
30 cm
16 LVDS input connectors(From Amp. & discriminator)
25cm
15cm
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Photo 7: A time of flight data acquisition circuit module
Photo 8: A prototype detector. A front view (a) and a rear view (b).
1 GB DRAM x 2 FPGA
16 M B SDRAM
1 GB DRAM x 2 FPGA
16 M B SDRAM
(a) F ront view (b) Rear view(a) F ront view (b) Rear view
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Fig. 20: A prototype 2-d WLSF detector system. A block diagram (a) and detector system (b).
Fig. 21: A collimated neutron beam measured with a prototype detector summed over whole time of flight. A 2-d image (a) and a sliced spectrum at the peak (b).
LVDS signal cable10 m
1m
1 2 3
6 5 4
A. High position resolution neutron imaging detector
Main computersystem
VME Power Supply
ETHER-NET
LVDS Cable(~10 m)
DataAcqui-sitionmodule
CPUModule
or(SiTCP)
Signal processingmodule with FPGA
2 x 256 ch.amplifier &discriminator
Scintillator
Detector
WLS photon readout pack
B4C light fiber block
64 ch read out circuit
64 ch Multianode PMT
B. TOF data acquisition system
A. High position resolution neutron imaging detector
Main computersystem
VME Power Supply
ETHER-NET
LVDS Cable(~10 m)
DataAcqui-sitionmodule
CPUModule
or(SiTCP)
Signal processingmodule with FPGA
2 x 256 ch.amplifier &discriminator
Scintillator
Detector
WLS photon readout pack
B4C light fiber block
64 ch read out circuit
64 ch Multianode PMT
B. TOF data acquisition system
LVDS signal cable10 m
1m
1 2 3
6 5 4
A. High position resolution neutron imaging detector
Main computersystem
VME Power Supply
ETHER-NET
LVDS Cable(~10 m)
DataAcqui-sitionmodule
CPUModule
or(SiTCP)
Signal processingmodule with FPGA
2 x 256 ch.amplifier &discriminator
Scintillator
Detector
WLS photon readout pack
B4C light fiber block
64 ch read out circuit
64 ch Multianode PMT
B. TOF data acquisition system
A. High position resolution neutron imaging detector
Main computersystem
VME Power Supply
ETHER-NET
LVDS Cable(~10 m)
DataAcqui-sitionmodule
CPUModule
or(SiTCP)
Signal processingmodule with FPGA
2 x 256 ch.amplifier &discriminator
Scintillator
Detector
WLS photon readout pack
B4C light fiber block
64 ch read out circuit
64 ch Multianode PMT
B. TOF data acquisition system
(a) 2-d image (b) 1-d spectrum
0
1000
2000
3000
4000
0 5 10 15 20 25Channel
Cou
nts,
a.u
.
DataGaussian fit
FWHM = 2.0 mm
(a) 2-d image (b) 1-d spectrum
0
1000
2000
3000
4000
0 5 10 15 20 25Channel
Cou
nts,
a.u
.
DataGaussian fit
FWHM = 2.0 mm
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Fig. 22: Time of flight spectra in the area of neutron count peak.
Photo. 9: Experimental setup in the ROTAX port at ISIS pulsed neutron source. Two prototype 2-d WLSF detectors were set up at the angle positions of 45 and 90 degree.
1
10
100
1000
0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000
Coun
t
Time of flight [us]
ISIS ROTAX, Direct beam with slit, 2008-3-12
1.0-us 2-4P coinc1.5-us 2-4P coinc2.0-us 2-4P coinc4.0-us 2-4P coinc
1
10
100
1000
0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000
Coun
t
Time of flight [us]
ISIS ROTAX, Direct beam with slit, 2008-3-12
1.0-us 2-4P coinc1.5-us 2-4P coinc2.0-us 2-4P coinc4.0-us 2-4P coinc
Detector 1Detector 2
Ni rod
Detector 1
Detector 2
neutron Detector 1Detector 2
Ni rod
Detector 1Detector 2
Ni rod
Detector 1
Detector 2
neutron
Detector 1
Detector 2
neutron
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Fig. 24: Scatter plot of neutron diffraction from a Ni rod sample.
Fig. 23: Diffraction images of Ni rod measured with a detector 1 and detector 2 at fixed time of flight.
(a) Detector 1 (b) Detector 2(a) Detector 1 (b) Detector 2
40
140
2
Wavelength (ToF)
40
140
2
Wavelength (ToF)
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Fig. 25: Time of flight spectra after time focusing correction.
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