計測システム研究会
@J-PARC
J-PARC/MLFにおける
2次元ガス検出器及び
シンチレータ検出器の開発
J-PARCセンター 物質生命科学ディビジョン
坂佐井 馨
MLFビームラインにおける検出器の現状
He-3 detectors
(commercially available)
Scintillator detectors
He-3 PSD
2-d compact
scintillator detector
using WLSF
BL01, BL02, BL08, BL09, BL11, BL12
BL14, BL15, BL16, BL17, BL20, BL21
Effective area:
128 x 128 mm2
1-d large area
scintillator detector
35 cm
Optical fiber
BL03
BL19
35 cm
MWPC
BL17
Multi-wire
proportional counter
BL16, BL17
RPMT
2-d large area
scintillator detector
using WLSF
BL18
Outline
 シンチレーション検出器の開発
- 1次元シンチレーション検出器
- 2次元シンチレーション検出器
 2次元ガス検出器の開発
- マルチワイヤ型検出器
MLFにおけるシンチレーション検出器
BL19(Takumi) Residual stress diffractometer
(2007 – 2009)
Linear scintillation detector
BL18(Senju)
Single crystal diffractometer
(2010 - 2013)
BL03(iBIX)
Bio-single crystal diffractometer
( 2007 – 2008, 2011 - )
2-D detector using WLSF
2-D detector using WLSF
Outline
 シンチレーション検出器の開発
- 1次元シンチレーション検出器
- 2次元シンチレーション検出器
2次元ガス検出器の開発
- マルチワイヤ型検出器
BL19における1次元シンチレーション検出器
Developed under collaboration with ISIS, RAL
Neutron
Sample
Number of detectors: 10
Specifications of Detectors
Detectors
The detector should have
 Sensitive area: 1000 mm x 200 mm
 Position resolution: 3mm
 360 pixels / detector
 Detection efficiency: >50%@1Å
 Gamma sensitivity: <[email protected]
(each 5 installed at 2q=90 degree position)
TAKUMI: Engineering Materials Diffractometer for Residual Stress Analysis
BL19における1次元シンチレーション検出器
Scintillation Detector using ZnS/LiF
805mm
1370mm
217mm
Neutrons
Senstive Area
（1m×20cm）
Detector size without PMT：805×1370×217mm
Detector size with PMT: 805×～2000×217mm
Sensitive area：1m×20cm
Radius curvature：R=2m
weight：～120kg（without PMT）
weight：～180kg（with PMT）
Number of PMT：48/detector
Number of Pixels: 360
Resolution：3mm
BL19検出器のヘッドの構造
Scintillator & grids
Venetian Head
 Detection of scintillation light
from both sides of scintillator
 Increase of detection efficiency
using scintillators tilted to neutron
direction(Effective thickness increased)
Scintillators
(ZnS/6LiF)
Neutrons
Reflectors
resolution
： 3mm
Neutron
Scintillators
(ZnS/6LiF)
Reflectors
Fibers
Scintillators
B4C Block
PMT & DAQ
6Li
+ n→3H + a+ 4.8 MeV
The scintillation light
was collected with
optical fibers and sent
to PMT and Data
acquisition system
BL19検出器の性能
Gamma sensitivity
Uniformity measured with PE rod
No.3
1400
1200
1000
800
600
400
200
0
-4
10
5.5%@std.dev
0
50
100
150
200
250
300
350
Counts/100s
No.4
1400
1200
1000
800
600
400
200
0
Gamma sensitivity
Detector 1
Detector 2
-5
10
-6
10
-7
10
-8
10
50
100
150
200
channel number
250
300
150
200
250
300
350
Threshold level (-mV)
4.7%@std.dev
0
100
350
Gamma sensitivity <10-6
with a 60Co source
(at discri. level of 250mV)
BL19TAKUMI検出器
• 3mm position resolution
• Detection efficiency: >50%@1Å
• Gamma sensitivity: <[email protected]
• 3×196mm detector element
• 360ch/detector
• Total 10 detector
• Total 3600 elements
• 2.0m2 active area
• 75°<2q＜105°
Total 10 detectors were
installed and have been in
service for several years
Outline
シンチレーション検出器の開発
- 1次元シンチレーション検出器
- 2次元シンチレーション検出器
2次元ガス検出器の開発
- マルチワイヤ型検出器
BL03における2次元シンチレーション検出器
• iBIX : Single crystal diffractometer for bio-molecular crystallography
• A first WLS-fiber-based scintillator detector developed at the J-PARC.
Specifications required to detector
Detection efficiency : > 50% (1.8Å)
Spatial resolution : < 1 mm
Gamma sensitivity : < 10-6
Packing density : ～70%
Compact
Prototype detector (in 2008)
256 x 256 ch
imaging detector
with WLS readout
Signal processing
module with FPGAs
High speed amplifier
discriminator module
iBIX検出器のヘッド構造
iBIX structure
Conventional structure
neutron
WLS fibres
neutrons
Ｙ
Ｘ
Neutron-sensitive scintillator
Single Scintillator screen
(1) Developed a ZnS/10B2O3 scintillator
and double the number of screens
Double scintillator screens
 High detection efficiency
(2) Packed ½-mm diameter WLS fiber ribbons  High spatial resolution
iBIX検出器の位置分解能
Edge Spread function:
1.4
exprimental data
fitted cumulative distribution function
Relative intensity
1.2
without Gd mask
1
Fitting parameters
A = 0.5 → 0.4483
B = 0.1 → 0.09343
μ = 50 → 50.41
σ = 0.5 → 0.5082
0.8
255
0.6
Y
0.4
Gd mask
with Gd mask
0.2
0
0
X
0
0
20
40
60
Spatial resolution (FWHM)
Position (x axis) [mm]
= SQRT(2log2) σ
~ 2.3548 σ
= 1.19 [mm], including beam divergence
80
255
100
BL18(Senju)の2次元シンチレータ検出器
* SENJU : A time-of-flight Laue single crystal diffractometer
* A large area position-sensitive scintillator detector
using WLS fiber technology
Specifications
required to detector
Spatial resolution : ~4 mm
Detection area : ~30 x 30 cm2
Detection efficiency : >40%@1.8Å
Gamma-ray sensitivity : < 10-6
Detector head
Signal processing
& Encoder electronics
DAQ
electronics
T. Nakamura, et al. NIMA686(2012)64.
BL18検出器のヘッド構造
In the design, to increase a detector coverage at an affordable cost
the WLS fibers are placed at a regular pitch of 4 mm.
③ Clear fibers
①
WLS
fibers
neutron
②ZnS/10B2O3
scintillators
Key Designs
Scintillator (front)
(1) WLS fiber placed at a 4-mm pitch  Large area
(2) Two scintillator screens  Detection efficiency
(3) Bend clear fiber backward Minimize dead area
BL18検出器の性能
Collimator
Collimator
Count
stability over time
Det12-01(SCDD01_DS-01)
1.2
Image plate
1
1.2
SCD detector
relative counts
0.6
0.4
Spatial resolution : 4 mm
1.0
0.9
0.8
Detectors were stable
after >400 days
Earthquake
0.7
0.6
0.2
0.5
0
0
20
25
30
35
100
40
200
300
elapsed time, days
400
500
position. mm
Detector efficiency of 37+2 detectors
Gamma sensitivity
vs Detection efficiency of 30 detectors
60
production date: 2010.10
2013.1
50
Detection efficiency
～40%@1.8Å
Gamma-ray sensitivity
～[email protected]
detection efficiency, %
intensity, a.u.
1.1
Pencil beam
( ~3 mm in width, 4 Å)
0.8
40
30
20
Mass production technique is acceptable.
10
0
1
3
5
7
9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39
detector number
波長シフトファイバを用いたシンチレーション検出器
BL03(iBIX)
BL18(SENJU )
300 x 300 mm
信号処理&
データ収集系
High spatial resolution detector
pixel size : 0.5 x 0.5 mm
detective area : 133 x 133 mm2
detector efficiency: ~50% for 1.8Å
gamma sensitivity: ~1 x 10-6
Total 30 detectors were installed
and in service now
Large area detector
pixel size : 4 x 4 mm
detective area : 256 x 256 mm2
detector efficiency: ~40% for 1.8 Å
gamma sensitivity: ~ 3 x 10-6
Total 37 detectors were installed
and in service now
Outline
シンチレーション検出器の開発
- 1次元シンチレーション検出器
- 2次元シンチレーション検出器
 2次元ガス検出器の開発
- マルチワイヤ型検出器
BL17におけるマルチワイヤ型検出器
Sharaku: Polarized Neutron
Reflectometer
35 cm
Optical fiber
35 cm
MWPC system
Installed in MLF/BL17
Pressure vessel withstanding up to 8 atm
Multi-wire type detector element
Wire pitch: 1 mm
Sensitive area: 128 x 128 mm2
ASD-ASIC for multi-channel signal processing
Individual line readout
Optical signal transmission
Effective area:
128 x 128 mm2
開発したMWPCの性能評価
Irradiation experiments were
performed
using Cf-252
at KUR/CN3
at J-PARC/MLF BL17
MWPC
MWPC
Performances of MWPC
 Counting uniformity
 Position resolution
103
 Output Linearity
102
Measured by developed detector
■ Reactor monitor
●
With Cf-252
1.2x10
X projection
1.8 mm FWHM
100
100
10-1
10-1
10-2
10-2
10-3
10-3
10-4
104
4
1D uniformity
X: 3.5%
Y: 4.6%
200
4
2x10
20
25
30
Position (mm)
35
40
Counts (cps)
Standard deviation
1st. cathode: 3.8%
2nd. cathode: 4.6%
4
6x10
4
15
10-6
1000
500
Elapsed time (s)
Good linearity
103
4x10
0
10
10-5
105
8x10
600
0
5
5
400
At KUR
10-4
1x10
Counts
Measured signal (counts)
800
101
10-5
-500
beam size: 0.3 x 0.3 mm2
1000
101
101
20
40
60
80
Position (mm)
100
> 5 decades!
100
0
0
102
120
10-1
10-5
10-4
10-3
10-2
10-1
Reactor Power (MW)
100
101
Reactor power (MW)
Measured counts (kcps)
102
Summary
計測システム研究会
@J-PARC
まとめ
 中性子検出器は中性子散乱実験等において、非常に重要な役
割を果たしており、このため、我々はJ-PARC/MLFにおいて、様々
な中性子検出器を開発してきた。
シンチレーション検出器に関しては,
 BL19に対しては、大型の1次元検出器を開発した。BL03及び
BL18に対しては波長シフトファイバを用いた2次元検出器を開発
した。これらの検出器は共用開始後順調に稼働している。
ガス検出器に関しては、
 BL17において、マルチワイヤ型検出器（MWPC）を開発した。位
置分解能や一様性等のMWPCの性能をKUR等で確認した。