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弘中 浩太; Lee, J.; 小泉 光生; 伊藤 史哲*; 堀 順一*; 寺田 和司*; 佐野 忠史*
Nuclear Instruments and Methods in Physics Research A, 1054, p.168467_1 - 168467_5, 2023/09
被引用回数：0 パーセンタイル：0.02(Instruments & Instrumentation)We propose neutron resonance fission neutron analysis (NRFNA), an active nondestructive assay (NDA) technique, to improve the capability to identify and quantify a small amount of fissile material in a sample. NRFNA uses pulsed neutrons to induce fission reactions in the sample. Fission neutrons are detected by a neutron-gamma pulse shape discrimination (PSD) scintillation detector with time-of-flight (TOF) technique. The obtained nuclide-specific resonance peaks in the neutron energy spectrum provide information to identify and quantify a fissile material in the sample. The possibility of using PSD for NRFNA was confirmed through a test experiment using a natural uranium sample. We successfully observed the resonance peaks from 
U(n,f) reaction and showed that NRFNA would be useful for measuring a small amount of fissile material in a sample.
Grazzi, F.*; Cialdai, C.*; Manetti, M.*; Massi, M.*; Morigi, M. P.*; Bettuzzi, M.*; Brancaccio, R.*; Albertin, F.*; 篠原 武尚; 甲斐 哲也; et al.
Rendiconti Lincei. Scienze Fisiche e Naturali, 32(3), p.463 - 477, 2021/09
被引用回数：3 パーセンタイル：21.07(Multidisciplinary Sciences)In this paper, we have studied an additively manufactured metallic component, intended for ultra-high vacuum application, the exit-snout of the MACHINA transportable proton accelerator beam-line. Metal additive manufacturing components can exhibit heterogeneous and anisotropic microstructures. Two non-destructive imaging techniques, X-ray computed tomography and Neutron Tomography, were employed to examine its microstructure. They unveiled the presence of porosity and channels, the size and composition of grains and intergranular precipitates, and the general behavior of the spatial distribution of the solidification lines. While X-ray computed tomography evidenced qualitative details about the surface roughness and internal defects, neutron tomography showed excellent ability in imaging the spatial density distribution within the component. The anisotropy of the density was attributed to the material building orientation during the 3D printing process. Density variations suggest the possibility of defect pathways, which could affect high vacuum performances. In addition, these results highlight the importance of considering building orientation in the design for additive manufacturing for UHV applications.
土屋 晴文; 北谷 文人; 藤 暢輔; Paradela, C.*; Heyse, J.*; Kopecky, S.*; Schillebeeckx, P.*
Proceedings of INMM 59th Annual Meeting (Internet), 6 Pages, 2018/07
In fields of nuclear safeguards and nuclear security, non-destructive assay (NDA) techniques are needed in order to quantify special nuclear materials (SNMs) in nuclear fuels. Among those techniques, active NDA ones would be preferable to passive ones. One candidate of active NDA techniques is neutron resonance transmission analysis (NRTA). In fact, experiments done at GELINA have shown that NRTA has high potential enough to quantify SNMs in complex materials. Currently, such a NRTA system requires a large electron accelerator facility to generate intense neutron sources. In other words, it is very difficult to perform NRTA at various facilities that need to measure SNMs. Thus, downsizing a NRTA system would be one solution of its difficulty. In order to realize a compact NRTA system, we develop a prototype with a D-T neutron generator that has a pulse width of 10 
s. For this aim, numerical calculations to optimize the compact NRTA system were done. In addition, NRTA measurements with simulated fuel pins were made at neutron time-of-flight facilities such as GELINA. In this presentation, we present results of the numerical calculations and the experimental results. On the basis of those results we discuss a future prospect of a compact NRTA system that would be applicable to SNM quantification. This research was implemented under the subsidiary for nuclear security promotion of MEXT.
中西 友子*; 岡野 健*; 唐鎌 勇*; 石原 猛*; 松林 政仁
Holzforschung, 52(6), p.673 - 676, 1998/00
4種類の杉の胸の高さから1cm厚の小口材を採取し、乾燥過程における水分の像を得るために熱中性子ラジオグラフィ撮影を行った。水分量の変化は撮影後の画像から画像解析により求めた。その結果、初期の水分分布には3種類あり、第一は、心材と辺材の間に位置する白線帯を除き一様に水分が分布しているもの、第二は、白線帯における水分分布は類似しているものの、水分が低下している領域が辺材方向に伸びているものであり、第三は、辺材部と心材部の水分量が各々高低となっているものである。心材部における水分含量が高い場合には、乾燥過程において心材部の水分量が残存する傾向が示された。
田村 則
Radiochem.Radioanal.Lett., 18(3), p.135 - 142, 1974/03
非破壊中性子放射化分析により、石炭およびベリリウム中の微量元素を多元素同時定量する方法を確立した。試料と同時に照射した標準コバルトを使って中性子束を決定し、各元素量は核データの文献値を使って放射化計算式から求める。この方法による定量値を他の方法で得られた分析値と比較して、本法による定量の正確さを吟味した。その結果、日常分析として十分満足できる正確さで定量できることがわかった。
