実験報告書様式（一般利用課題・成果公開利用）

MLF Experimental Report

2016/1/15
装置責任者 Name of responsible person

課題番号 Project No.

Yosuke Toh (BL04),

2014BU0410

Kenichi Oikawa (BL10)

実験課題名 Title of experiment
Measurement

提出日 Date of Reportofleakage

neutronbrightness

from

装置名 Name of Instrument/（BL No.）

para-hydrogen coupled moderators for ESS moderator

BL04 ANNRI

development

BL10 NOBORU
実施日 Date of Experiment

実験責任者名 Name of principal investigator

2015/4/10 – 2015/4/11(BL10)

Masahide Harada

2015/4/11 – 2015/4/12(BL04)

所属 Affiliation
JAEA

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.
None

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.

The nGEM detector [1], which was a gaseous ionization chamber using boron films, prepared for the neutron
imaging experiment at BL22, was used for the measurement. Two measurements were done at BL10 for thedecoupled moderator and at BL04 for the coupled moderator. At BL10, the detector was located at 13 m anda tiny collimator (3.1 x 3.1 mm) in the rotary collimator at 8.0 m was used. At BL04, the detector was locatedat 28.5 m and a pinhole Cd plate with a hole of 3 mm in diameter was placed at 21.5 m.
Figure 1 shows the neutron spatial brightness around 5 meV from the decoupled moderator (BL10). The
figure on the left shows the measurement result and the one on the right depicts the simulation. Thesimulation was done by PHITS [2] calculation with the engineering model of JSNS [3]. It was found that thedistributions of the two sets of data were very similar with the highest intensities at the center. Also, an
aluminum tube in the moderator was observed (the two vertical lines near the center).

12. 実験方法及び結果（つづき） Experimental method and results (continued)
Figure 2 shows the neutron spatial brightness around 5 meV from the coupled moderator (BL04). In thesame way as in Fig.1, the figure on the left shows the measurement result and the one on the right depicts thesimulation. It was found that the distributions of the two sets of data were very similar and the highest
intensities were observed near the target (upper side) and far from it (lower side).
The particular spatial brightness from the coupled moderator is of great interest to us and it is very
important to measure these data for the moderator in a high-power spallation neutron source. These results
validated the JSNS neutronic design. And they would be also very helpful for the ESS design.

Figure 1: Neutron spatial distribution from the de-coupled moderator (BL10)
Left: measurement; right: simulation

Figure 2: Neutron spatial distribution from the coupled moderator (BL04)
Left: measurement; right: simulation
Acknowledgement
The authors thank to the staffs of BL04 and BL10 for very helpful supports.
Reference[1] S. Uno et al, Physica Procedia, 26, 142 (2012)[2] T. Sato, J. Nucl. Sci. Technol. 50, 913 (2013)[3] M. Harada, et al., Prog. Nucl. Sci. Technol., 2, 872 (2011).

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