実験報告書様式（一般利用課題・成果公開利用）（ ※本報告書は英語で記述してください。ただし、産業利用課題として採択されている方は日本語で記述していただいても結構です。 ）MLF Experimental Report
課題番号 Project No.

提出日 Date of Report
8 Aug., 2017
装置責任者 Name of responsible person
Tatsuya Nakamura

2014B0241
実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Development of neutron detectors

BL 10実験責任者名 Name of principal investigator

実施日 Date of Experiment

Tatsuya Nakamura

2014 12/16-17, 12/21-22

所属 Affiliation

2015 4/15-16

Japan Atomic Energy Agency, J-PARC center2016 6/16-6/18

試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.
In foil, Au foil

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results. If you failed to conduct experiment as planned, please describe reasons.
Three types of scintillation neuron detectors have been developed in house aiming for applications in theJ-PARC MLF. The detector performances were evaluated by using a pulsed neutron beam in the BL10. Our
ideas implemented in the detectors have all functioned successfully. The experimental results obtained within
the available beam terms are summarized below.
(1) A time-of-flight neutron imager using a ZnS scintillator/wavelength-shifting fiber with a fiber optic taper
We aimed at developing a 100-m spatial resolution neutron detector in a cost effective way, by combing adeveloped wavelength-shifting (WLS) fiber technology with a fiber optic taper (FOT). The key idea is tomeasure neutron transmission image with a fine diameter fiber (100 m) after expanding the scintillation
image with a FOT device. The detector comprises a thin scintillation screen (100 m), WLS fiber, and FOT(image expanding rate of three). The detector exhibited a spatial resolution of about 60 m. Moreover asuperior gamma-ray sensitivity of 10-8 was achieved. The detector measured transmission images of Au/Infoils successfully, demonstrating a good temporal resolution. Although the detector had limited count ratecapability (<20 kcps), we demonstrated one of the solutions to provide a 100-m resolution detector.
effective, robust, easy to use the detector

12. 実験方法及び結果（つづき） Experimental method and results (continued)(2) A large area position-sensitive scintillation neutron detector as an alternative to 3He PSDs
In order to develop a detector technology that can be alternative to 3He PSDs a large area neutron detector
has been produced by using scintillator/WLS fiber technology. The detector structure is somehow similar to“conventional” SENJU detector. Two key technologies have been developed for this detector. First thing is tocollect scintillation light from both sides of the WLS fiber. It increased the collected light by a factor of 1.8.
Second technology is to develop a spring-driven fiber pulling jig. This mechanical device keeps the fibers in aproper position with an appropriate tension. We produced the detectors that has a size of 32×32 cm2 and 64
×64 cm2. Those detectors exhibited a similar detection efficiency to that of SENJU detector, demonstrating

detection efficiency relative tosenju

the feasibility of the large area detector with the developed detector technologies.

5 mm pitch

Potting into together
Light intensity x1.84

1.9A

1.2
1.0
0.8
0.6
0.4
0.2
0.0
Det64

Det32

Senju

(3) A 2.5-mm spatial resolution two-dimensional detector for jBIX instrument in the J-PARC MLF
A first prototype detector which is dedicated to a planned protein single crystal neutron diffractometer in
MLF was developed. The detector performances are evaluated by using a collimated beam (1×1 mm2) in
BL10. The detecting head structure is similar to that in SENJU. The detector is designed compact, lightweight,
and modular in order to fit several tens detectors in a space-limited blockhouse. The detector has a size of 38×38×46 cm3 and it weighted 20 kg. The 128 WLS fibers placed in a regular gap of 2.5 mm for both in x and ydirections. The detector exhibited a spatial resolution of 2.5 mm and a superior position linearity (The deviationfrom the linear fit is less than 0.2% ). A count uniformity measured with flood irradiation with moderated
neutrons was 13% (= sigma/average), which is acceptable to jBIX.
Amp/disci 信号処理部
DSP/Encoder
アンプ部

350300250
1400200

1200150100010050

y = 0.9983x-0.3145

Count per bin

position
Measured
測定位置(mm)(mm)

Detectorhead
検出ヘッド部

800
600
400
200

00

100

200

ビーム移動距離(mm)Beamposition (mm)

2300

01000

2000

3000

4000
Count

5000

6000