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

提出日 Date of Report

課題番号 Project No.

装置責任者 Name of responsible person

2012A0084

Kenichi Oikawa

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Neutron beam focusing with high performance supermirrors on

NOBORU/BL10

precisely figured surfaces

実施日 Date of Experiment

実験責任者名 Name of principal investigator2012/04/16-2012/04/20

Dai Yamazaki

2012/05/18-2012/05/22

所属 Affiliation

2012/06/13-2012/06/17

J-PARC Center, 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.
chemical formula: Cd
size: 10W x 10H x 1T mm3
The sample was not brought into MLF in the experiment but was equipped in MLF for beam-line shielding.

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 Experimental setup is illustrated and photographed in Fig.1.

Figure1: Experimental Setup.
12. 実験方法及び結果（つづき） Experimental method and results (continued)
The focusing geometry is based on an ellipsoid whose focal length is 1050+1050 mm. Neutron beam wastransversally narrowed by a slit at the first focal spot, reflected by a focusing mirror at 1050mm from both of
the focal points, and then transversally focused into the detector surface at the second focal point. The beam
was collimated vertically with a couple of slits: one is the slit at the first focal point and the other is placed justin front of the second focal spot. The beam-line was deflected by a flat supermirror (m=3) in order to get awayfrom direct beam which includes high-energy neutrons and gamma-rays.
A 2-dimensional profile of the transversally-focused and vertically-collimated beam is shown in Fig.2. The
profile was observed with a scintillation detector (RPMT). The focused beam size looks broadened due to thespatial resolution of the area detector although design value is 1 x 1 mm2.
Figure 2. Profile of the transversally-focused and verticallycollimated beam observed with a scintillation area detector.

A prompt-gamma activation analysis (PGAA) was performed using the intense and small beam. A cadmium
plate of 10W x 10H x 1T mm3 was placed at the second focal point and prompt-gamma-rays from the cadmium
plate were measured with a germanium detector. It should be noted that the germanium detector was notshielded at all in the measurement.
Figure 3 compares the spectrum of the prompt-gamma-rays and backgrounds. The measurement time was2000 seconds for prompt-gamma-rays and 600 seconds for background. Prompt-gamma rays from cadmium(558 keV) were clearly observed, which suggests neutron beam focusing should be very useful to PGAA on
small samples as large as 1 x 1 mm2 or smaller.
Figure 3. Prompt-Gamma-Ray measurement. Spectrumof prompt-gamma-ray from a cadmium plate of 10W x 10H
x 1T mm3 which was irradiated by the small beamtransversally focused vertically collimated into 1x1mm2.

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