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岩本 ちひろ*; 高村 正人*; 上野 孝太*; 片岡 美波*; 栗原 諒*; 徐 平光; 大竹 淑恵*
ISIJ International, 62(5), p.1013 - 1022, 2022/05
被引用回数：2 パーセンタイル：21.00(Metallurgy & Metallurgical Engineering)Neutron diffraction is a powerful non-destructive method for evaluating the microscopic structure and internal stress of metal plates as a bulk average. Precise neutron diffraction measurements with a high intensity neutron beam have already been carried out at large-scale neutron facilities. However, it is not easy to provide users with enough experimental opportunities. We are working on upgrading the neutron diffractometer with techniques of time-of-flight to enable stress measurements at RIKEN accelerator-driven compact neutron source (RANS). To improve neutron diffraction resolution, delayed neutrons, which expand neutron beam pulse width, should be suppressed. However, it is difficult to separate the delayed neutrons experimentally. In this study, a new analysis method has been proposed to deconvolute the diffraction peak from the delayed neutron component. Moreover, a new collimator system, called decoupled collimator system, has been developed to reduce the number of delayed neutrons. The diffraction patterns from a powder sample of pure body-centered cubic iron were measured with the decoupled collimator and the diffraction peak of {211} reflection was analyzed by the new analysis method using a model function of a single exponential decay function convoluted with a Gaussian function. By this method, the decoupled collimator system has been confirmed to achieve a smaller measurement limit of lattice strain 
than a small-aperture polyethylene collimator system and a non-collimator system. The currently available was 6.7
10
, this means that the internal stress up to 130 MPa can be well evaluated for steel materials with a Young's modulus of 200 GPa at RANS.
徐 平光; 高村 正人*; 岩本 ちひろ*; 箱山 智之*; 大竹 淑恵*; 鈴木 裕士
Isotope News, (774), p.7 - 10, 2021/04
近年、地球温暖化対策として、自動車などの軽量化に求められている中、高張力鋼板の成形性向上は重要な開発課題となっている。破断まで優れた伸び特性を持たせた高張力鋼板の開発には、オーステナイト組織の相分率と各構成相の集合組織を正しく制御することは極めて重要である。透過能に優れた中性子回折法は、鋼材内部の結晶情報をバルク平均で得られる特徴を持つことから、相分率と集合組織を測定する上で有力な手段である。しかし、現状では中性子回折測定が可能な中性子源は、研究用原子炉や大型加速器施設などの大型実験施設に限られ、これらは共用施設のため利用者が頻繁に測定する機会を得ることは困難である。そこで、理化学研究所では、大学や企業の研究室、工場などの現場で手軽に使える小型中性子源として「理研小型加速器中性子源RANS」を構築し、日本原子力研究開発機構と協力しながら鋼材特性の分析技術に関する一連の研究開発を進めてきた。本解説論文では、大型実験施設と比べるとビーム強度の低い小型加速器中性子源を用いて実施した、中性子回折法による相分率と集合組織測定に関する共同研究成果と、今後の展望を紹介する。
Pb近藤 壮雄*; 宇都宮 弘章*; Goriely, S.*; 岩本 ちひろ*; 秋宗 秀俊*; 山形 民穂*; 豊川 弘之*; 原田 秀郎; 北谷 文人; Lui, Y.-W.*; et al.
Nuclear Data Sheets, 119, p.310 - 313, 2014/05
被引用回数：2 パーセンタイル：18.54(Physics, Nuclear)Using linearly-polarized laser-Compton scattering 
-rays, partial E1 and M1 photoneutron cross sections along with total cross sections were determined for Pb at four energies near threshold by measuring anisotropies in photoneutron emission. Separately, total photoneutron cross sections were measured for Pb with a high-efficiency 4
neutron detector. The partial cross section measurement provides direct evidence for the presence of pygmy dipole resonance (PDR) in Pb near the neutron threshold. The strength of PDR amounts to 0.32% - 0.42% of the Thomas-Reiche-Kuhn sum rule. Several 
units of B(M1)
strength were observed in Pb just above neutron threshold, which correspond to M1 cross sections less than 10% of the total photoneutron cross sections.
,n) and (n,)reactions宇都宮 弘章*; Goriely, S.*; 近藤 壮雄*; 岩本 ちひろ*; 秋宗 秀俊*; 山県 民穂*; 豊川 弘之*; 原田 秀郎; 北谷 文人; Lui, Y.-W.*; et al.
Physical Review C, 88(1), p.015805_1 - 015805_6, 2013/07
被引用回数：80 パーセンタイル：96.69(Physics, Nuclear)Photoneutron cross sections were measured for 
Mo,
Mo,
Mo, 
Mo,
Mo, and 
Mo near the neutron threshold with quasi-monochromatic laser-Compton scattering -rays. The photoneutron data were analyzed with the Skyrme Hartree-Fock-Bogoliubov (HFB) plus quasiparticle random phase approximation (QRPA) model and the axially-symmetric-deformed Gogny HFB plus QRPA model of E1 -ray strength. Combining the -ray strength function constrained by the present photoneutron data with either the nuclear resonance fluorescence data or the updated Oslo data to supplement the data below the neutron threshold, a thorough analysis of the reverse (n,) cross sections is made whenever measurements are available. The Oslo data and the corresponding uncertainties are updated based on the latest results of the s-wave neutron spacing and the average radiative width determined in particular for Mo.
-ray strength function method; A Way from photoneutron emission to radiative neutron capture宇都宮 弘章*; 秋宗 秀俊*; 山県 民穂*; 岩本 ちひろ*; Goriely, S.*; Daoutidis, I.*; 豊川 弘之*; 原田 秀郎; 北谷 文人; 岩本 信之; et al.
Proceedings of 14th International Symposium on Capture -Ray Spectroscopy and Related Topics, p.505 - 514, 2013/05
Radiative neutron capture cross section are of direct relevance for the synthesis of heavy elements referred to as the s-process and the r-process in nuclear astrophysics and constitute basic data in the field of nuclear engineering. The surrogate reaction technique is in active use to indirectly determine radiative neutron capture cross sections for unstable nuclei. We have devised an indirect method alternative to the surrogate reaction technique on the basis of the -ray strength function (-SF), a nuclear statistical quantity that interconnects photoneutron emission and radiative neutron capture in Hauser-Feshbach model calculation. The primary strength of the -SF is low-energy E1 strength in the tail of GDR. We outline the -SF method and show application of the method to Zr, Pd and Sn isotopes. In the application of the -SF method, it is important to use -SF, which incorporates extra strengths of PDR and/or M1 resonance emerging around neutron threshold.
近藤 壮雄*; 宇都宮 弘章*; Goriely, S.*; Daoutidis, I.*; 岩本 ちひろ*; 秋宗 秀俊*; 岡本 明之*; 山県 民穂*; 鎌田 正輝*; 伊藤 修*; et al.
Physical Review C, 86(1), p.014316_1 - 014316_7, 2012/07
被引用回数：40 パーセンタイル：86.72(Physics, Nuclear)レーザ逆コンプトン線と高検出効率4型中性子検出器を用いて、
Pbの中性子閾値近傍における全光核反応断面積を測定した。また、直線偏光させた線と中性子放出角の非等方性を測定することにより、Pbに対する
1及び
1励起による部分光核反応断面積を導出した。この結果、中性子閾値近傍においては1励起が支配的であることなど線強度関数に関する実験的知見を得た。
今泉 友見; 宮内 優; 伊藤 正泰; 綿引 俊介; 永田 寛; 花川 裕規; 那珂 通裕; 川又 一夫; 山浦 高幸; 井手 広史; et al.
JAEA-Technology 2011-031, 123 Pages, 2012/01
JAEA-Technology-2011-031.pdf:16.08MB
世界の試験研究炉は、老朽化に伴う廃炉により減少しているが、その一方でアジア諸国においては、原子力発電の導入計画が相次いでいる。このようなアジア諸国では、原子力発電所を建設した後の運転管理ができる技術者の育成が課題となっていると同時に、自国における原子力技術を高めるため、軽水炉の長期化対策,科学技術の向上,産業利用及び原子力人材育成のための試験研究炉の必要性が高まっている。このような背景から、照射試験炉センターにおいては、今後、発電用原子炉を導入する国に向け、各種照射利用や教育訓練に用いる試験研究炉の基本概念検討を開始した。設計活動を通じた本検討は、照射試験炉センターにおける試験研究炉の設計に必要な計算コードなどの環境の整備及び人材育成に貢献するとともに、本概念検討に共同研究として参加する原子力関連会社の試験研究炉にかかわる技術力の維持,向上にも貢献することが期待される。本報告は、平成22年度に設置された「照射試験炉センター汎用小型試験研究炉WG(ワーキンググループ)」と原子力関連会社が行った平成22年7月
平成23年6月までの試験研究炉の概念検討結果について取りまとめたものである。
Sn and the -ray strength function method宇都宮 弘章*; Goriely, S.*; 鎌田 正輝*; 秋宗 秀俊*; 近藤 壮雄*; 伊藤 修*; 岩本 ちひろ*; 山県 民穂*; 豊川 弘之*; Lui, Y.-W.*; et al.
Physical Review C, 84(5), p.055805_1 - 055805_6, 2011/11
被引用回数：45 パーセンタイル：89.79(Physics, Nuclear)
Sn, 
Sn, 
Sn, 
Sn、及び
Snに対し、中性子閾値近傍の光核反応断面積を準単色レーザ逆コンプトン光を用いて測定した。得られた測定データと既存の中性子捕獲データを、ピグミー共鳴を電磁双極子励起モードに組み込んだ計算コードにより系統的に解析した。本手法、いわゆる、線強度関数法を適用することにより、放射性核種
Sn及び
Snの中性子捕獲断面積を導出した。
SF method宇都宮 弘章*; Goriely, S.*; 秋宗 秀俊*; 山形 民穂*; 近藤 壮雄*; 岩本 ちひろ*; 岡本 明之*; 原田 秀郎; 北谷 文人; 後神 進史*; et al.
AIP Conference Proceedings 1377, p.255 - 259, 2011/10
被引用回数：0 パーセンタイル：0.00(Astronomy & Astrophysics)The -ray strength function (SF) interconnects radiative neutron capture and photoneutron emission as a common ingredient in the statistical model. Outlined here is an indirect method of determining radiative neutron-capture cross sections for unstable nuclei based on the -ray strength function. Application examples of the SF method are demonstrated.
SF method to palladium宇都宮 弘章*; Goriely, S.*; Arteaga, D. P.*; Daoutidis, I.*; 秋宗 秀俊*; 山県 民穂*; 近藤 壮雄*; 岩本 ちひろ*; 鎌田 正輝*; 伊藤 修*; et al.
AIP Conference Proceedings 1377, p.450 - 452, 2011/10
被引用回数：0 パーセンタイル：0.00(Astronomy & Astrophysics)Photoneutron cross sections were measured for 
Pd, 
Pd, and 
Pd with laser-Compton scattering -ray beams in an application of the SF method to a radioactive nucleus 
Pd. We present radiative neutron cross sections for Pd [6.510
y] obtained with the SF method.
Zr near threshold宇都宮 弘章*; Goriely, S.*; 秋宗 秀俊*; 山形 民穂*; 近藤 壮雄*; 岩本 ちひろ*; 伊藤 修*; 鎌田 正輝*; 井尾 雅則*; 楠瀬 幸一*; et al.
AIP Conference Proceedings 1377, p.447 - 449, 2010/10
被引用回数：0 パーセンタイル：0.00(Astronomy & Astrophysics)Photoneutron cross sections for Zr near neutron threshold were examined with a photon difference technique using laser Compton scattering -ray beams. The cross section decreasing in the vicinity of neutron threshold exhibited a steep rise within 150 keV above the threshold. We draw attention to a possible relation of this striking behavior to the 3P valence neutron resonance known in neutron capture in the mass region A 
90.
高村 正人*; 岩本 ちひろ*; 徐 平光; 角田 龍之介*; 栗原 諒*; 箱山 智之*; 池田 義雅*; 鈴木 裕士; 大竹 淑恵*
no journal, ,
High strength steels are becoming more and more important in automotive body structures for good weight reduction, providing further requirement in the balance between strength and formability. Numerical models in forming simulations taking into account the texture evolution may accurately analyze macroscopic plastic behavior, through referring to local surface texture measurement using Electron backscatter diffraction or X-ray diffraction. In contrast, neutron diffraction may measure the microstructure factors including bulk-averaged texture, enable to more deeply understand the mechanisms of deformation behavior. Such neutron diffraction studies usually require large-scale experimental facilities like a reactor and a large accelerator, so meet certain difficulty in the instrumental accessibility. To solve these problems, Riken Accelerator-driven Compact Neutron Source (RANS) has been developed. On-site evaluation of microstructural factors enables us to analyze metal deformation processes more efficiently. Authors have recently succeeded in accurately measuring the texture evolution of an IF steel and also in determining the retained austenite volume fraction of multi-phase steels, by optimizing the beam condition and layout of collimators, samples, detectors, etc. These results show the possibility of practical use of an in-house compact neutron source in laboratories of universities, research institutes and industrial firms.
徐 平光; 岩本 ちひろ*; 高村 正人*; 大竹 淑恵*; 栗原 諒*; 上野 孝太*; 片岡 美波*; 山本 和喜; Harjo, S.; 菖蒲 敬久
no journal, ,
Neutron diffraction can collect sample-volume averaged diffraction patterns due to the excellent penetrability and the coarse beam spot, valuable for investigating bulk microstructure changes of polycrystalline materials. In recent years, several neutron instruments in Japan have been employed for precise bulk texture evaluation. The engineering materials diffractometer attached with large sample stage and precise radial collimators at J-PARC has realized a reliably combined Rietveld texture evaluation, simultaneously providing crystallographic textures and other profile-analysis-related material parameters such as crystal structures, stress tensors. The RANS compact neutron source has enabled reliable bulk texture evaluation of steel materials through reasonably using a high stereographic angle resolution and a large sample-gauge volume. As a feed-back from the texture measurement technique based on RANS compact neutron source, recently, weak diffraction patterns step-by-step collected in very short time from RESA neutron diffractometer at JRR-3 have been utilized to realize the precise texture evaluation of various polycrystalline materials, 
, a standard rock material, and different steel materials.
徐 平光; 山本 和喜; 岩本 ちひろ*; 高村 正人*
no journal, ,
While the bulk crystallographic textures are usually evaluated through the relative difference in neutron diffraction intensities of polycrystal materials from various sample orientations, an irregular sample geometric shape (different from a sphere and a cube) has an evident effect on the stereographic orientation distribution of neutron diffraction intensities due to the change in locally diffracted gauge volume and the neutron penetration path, which disturbs the quantitative calculation of real preferred orientation of materials and leads to clear uncertainty in nondestructive bulk texture measurements of finished or semi-finished products. Here, the stereographic diffraction intensity distributions of several high strength low alloy steel samples with same microstructure and texture but in various shapes and sizes were measured using RESA angle dispersive neutron diffraction. By referring to the classic neutron attenuation correction theory, the absorption correction reliability was examined to enable that the relevant intensity ratios among the rolling direction, the normal direction, the transverse direction, etc. are almost consistent with the corresponding data from a referred cubic sample. In the poster session, the recalculated bulk textures using the intensity-corrected diffraction profiles of different shaped samples will be given out to make a further comparison and discussion.
山本 和喜; 徐 平光; 岩本 ちひろ*; 高村 正人*; 大竹 淑恵*; 菖蒲 敬久
no journal, ,
構造材の材料開発においては、材料の遅れ破壊,疲労破壊及び腐食の原因となる残留応力の低減並びに損傷破断の防止が求められており、これらのオンサイト評価が極めて重要とされている。こうしたことから、理研では小型加速器中性子源(RANS)を用いた回折計を開発しており、オンサイト評価を想定した中性子回折実験の材料開発及び工法開発の適用性を調査している。小型中性子源には測定精度の向上、測定時間の短縮等さまざまな課題があり、これまで実験的に最適な条件を模索してきたが、2021年度より中性子輸送シミュレーションによる評価を開始したところである。PHITS及びMVPを用いてMcStas用の線源コンポーネントを開発した。このコンポーネントを用いて2019年に実施したFe材の回折実験の再現を試みたところ、そのシミュレーション結果は実験で得られた回折線の特徴をよく捉えたものであった。今後、本手法を向上させ、小型加速器中性子源のオンサイト評価に係る課題解決のツールとして利用したい。
徐 平光; 山本 和喜; Harjo, S.; 菖蒲 敬久; 岩本 ちひろ*; 高村 正人*; 大竹 淑恵*; 小貫 祐介*; 佐藤 成男*; Liss, K.-D.*
no journal, ,
Texture as crystallographic preferred orientation of polycrystalline materials has attracted broad attention due to its important effects on mechanical and physical characteristics. Within both metals and ceramics, widespread applications of texture involve capabilities and simulations in sheet forming, additive manufacturing, while rocks and minerals also demonstrate such feature due to forming processes within the earth. Neutron diffraction can collect high statistical diffractograms due to an excellent penetration and a coarse beam spot, valuable for bulk investigations of microstructural changes and a characteristic response from polycrystalline materials. However, the available neutron instruments are quite limited in the world. We have developed various neutron texture measurement techniques using RESA at JRR-3, TAKUMI and iMATERIA at J-PARC, WOMBAT at ANSTO, and RANS at RIKEN, and obtained the following consensus: for a steady neutron source, the utilization of large area curved detectors together with multiple wavelengths texture analysis technique enables rapid and high precision angle dispersive neutron diffraction measurement; for a pulsed neutron source, the utilization of an optimized detector optical system with proper stereographic angle resolution (2
) and instrumental resolution (d/d) is much more valuable for improving the reliability of the time-of-flight neutron diffraction measurement, enabling the orientation feature of tiny amounts of a second phase in a round robin textured limestone sample has been recognized satisfactorily. For a compact neutron source, the selective usage of a high signal-to-noise ratio as well as the wavelength ranges of the time-of-flight neutron diffraction patterns obtained from an in-house texture measurement are effective to reduce the diffraction uncertainty during Rietveld texture analysis, improving instrumental accessibility for on-site applications.
岩本 ちひろ*; 栗原 諒*; 高村 正人*; 高橋 進*; 鈴木 康介*; 徐 平光; 大竹 淑恵*
no journal, ,
中性子回折測定は、鉄鋼材料に溶接加工や鍛造加工を施した際に発生する残留応力を非破壊かつ定量的に測定できる最適な手法である。小型中性子源による中性子回折測定の実現は、このような測定のものづくり現場でのオンサイト測定を可能にし、材料加工研究開発のさらなる加速要望に応えるために必須である。一方で、中性子回折による応力測定には、回折線ピークの微小なシフトを測定するために高い回折線測定分解能が必要である。回折線分解能向上のためには、チョッパー機構やポイズンモデレータなどの短パルス化デバイス導入が一般的である。しかしながら、これらのデバイスは、ビーム強度の低下に直結し、かつ追加遮蔽導入によるシステムの大型化にもつながるため、中性子ビーム強度の低い小型中性子源の現場導入を前提とした開発には不向きである。本研究では、線源より下流側で中性子ビームの長パルス化を引き起こす"遅延中性子"に着目し、中性子ビーム強度と回折線測定分解能の間のトレードオフの関係を打開するための2つの開発を行なった。ひとつは、遅延中性子の発生を防ぐ非結合型コリメータシステムの開発、もうひとつは遅延中性子による長パルス化の影響を分離できる新しい回折線フィッティング関数を導入した解析法である。理化学研究所の小型加速器中性子源RANSのビームラインで、これらの手法を取り入れて、S45C試料に応力を付加させた既知応力サンプルからの中性子回折線を測定した。その結果500MPaの圧縮応力を格子ひずみから同定することに成功した。
岩本 ちひろ*; 栗原 諒*; 高村 正人*; 高橋 進*; 鈴木 康介*; 徐 平光; 大竹 淑恵*
no journal, ,
Neutron diffraction is a powerful non-destructive method for evaluating the microscopic structure and internal stress of metal as a bulk average. To implement on-site stress measurements via the neutron diffraction at laboratories and factories frequently and even daily, we are working on improving the method of the neutron diffraction measurement and analysis with techniques of time-of-flight to at RIKEN accelerator-driven compact neutron source (RANS). In this study, we have proposed two methods to improve the determination resolution of the diffraction peak position by focusing on delayed neutrons due to scattering from devices such as reflector surrounding the moderator and the polyethylene collimator. First, an analysis method has been proposed to deconvolute original diffraction peak from the delayed neutron component by defining a model function describing the delayed neutron shape. Second, a new collimator system, called decouple collimator, to reduce the number of delayed neutrons has been developed. In this presentation, we will show following two results: First, the performances of these new methods were evaluated to measure diffraction patterns from a powder sample of pure body-centered cubic iron with the decouple collomator, and to analyze the diffraction peak of {211} reflection by the new analysis method using a model function of a single exponential decay function convoluted with a Gaussian function. The diffracted neutron yield increased by a factor of 2 comapred with a traditional small-apperture polyethylene collimator system while the diffraction peak was successfully separated clearly from the delayed neutron component. Second, a trial stress measurement of a carbon steel specimen applied to as-known compressive stress was performed. At present, the applied stress can be measured with an error of up to 200 MPa for the specimen with applied stress of 500 MPa.
徐 平光; Wang, Y. W.*; Su, Y. H.; 岩本 ちひろ*; Wang, H. H.*; 浜 孝之*; 柴山 由樹; 土川 雄介; Parker, J. D.*; 甲斐 哲也; et al.
no journal, ,
For achieving the carbon neutralization through reducing the greenhouse gas emission, the liquefied natural gas (LNG) has been widely employed as the fuel for electric power plants. As economical cryogenic steel for LNG transport and storage, high-Mn steels have been paid much attention for a high possibility to replace expensive high-Ni martensite steels and high Ni-Cr austenite steels. Its superior cryogenic toughness is thought mostly due to the high thermal stability of austenite even at the LNG storage temperature and the evident mechanical twining effect during the cryogenic deformation. Since four-point bending deformation may induce elastoplastic strain and texture gradient distribution valuable to investigate the twinning effect, it is highly expected to carry out the in-situ/ex-situ cryogenic bending deformation experiment for clarifying the shear-induced twinning mechanism. As a preliminary research, cold-bent samples of high-Mn austenite thick steel plates at room temperature were employed to evaluate the twinning-induced shear band microstructure and confirm the 2D mapping of texture gradient distribution using time-of-flight (TOF) Bragg-edge transmission imaging. Comparably, the quantitative change in triaxial strains and crystallographic texture characteristics at five different regions along the bend radius was evaluated for reference using the angle-dispersive neutron diffraction. The conventional electron backscattering diffraction (EBSD) was employed to provide the direct morphologic information of gradient microstructure of cold-bent high-Mn steel plates. The RADEN neutron transmission profiles obtained from the inner surface layer to the 1/2 thickness layer of cold bent sample show an very interesting preferred orientation charactersitics, quite similar with the density distributions of corresponding orienations of complete pole figures obtained from RESA.
徐 平光; 岩本 ちひろ*; 山本 和喜; 諸岡 聡; 高村 正人*; Wu, S.*; 大竹 淑恵*; 菖蒲 敬久
no journal, ,
Considering the large potential applications of neutron diffraction techniques, close cooperation has been carried out to realize the rapid development of various neutron instruments, involving in the steady-state reactor neutron source at Japan Research Reactor No.3 (JRR-3), the large spallation neutron source at J-PARC, the compact neutron source at RANS. Based on the experience of developing the TAKUMI time-of-flight texture measurement technique at J-PARC neutron facility, the high stereographic angle resolution has been utilized to the panel division of the RANS neutron position-sensitive detector to realize the bulk texture evaluation of IF steel using a compact neutron source. Furthermore, the angle dispersive neutron diffractograms from all sample orientations during the RESA neutron diffraction experiment at JRR-3 neutron facility have been employed to carry out the Rietveld texture analysis simultaneously and to realize the reliable texture evaluations of complex crystal structure materials. Nondestructive stress measurement contributes significantly to the design and manufacture of mechanical structures aimed at high performance, high reliability, and long life, and improves the reliability and structure integrity of a wide range of machinery and structures, including machine gears, high-speed train axles, automobile and rocket engines, infrastructure structures, and welded structures simulating power plants, etc. Our recent neutron transport simulation about RANS has already reproduced the measured compact neutron diffractograms of BCC Fe powder at various stereographic orientations, suggesting the future simulation work will be highly valuable to optimize the related technical conditions of RANS neutron instruments for compact stress measurements.
