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大塚 直彦*; Devi, V.*; 岩本 修
Applied Radiation and Isotopes, 225, p.111903_1 - 111903_18, 2025/11
被引用回数：0We developed a set of EXFOR utility codes (ForEXy) to process the information of the experimental nuclear reaction data stored in the EXFOR library. We designed a new JSON format (J4) for the EXFOR library, and developed a code converting the information in an EXFOR file to a J4 file (X4TOJ4) and another code converting it to an EXFOR file (J4TOX4) as a core part of this new code package. We also developed some other codes for management of the EXFOR storage, bibliography and dictionary. As an application of the new code package, we constructed covariance matrices for the fast neutron induced fission cross sections of neptunium-237 in the EXFOR library by using the new codes, and applied them to evaluation of the cross section between 100 keV and 200 MeV.
鎌田 創*; 平尾 好弘*; 須山 賢也; 岩本 修
日本原子力学会誌ATOMO
, 67(4), p.238 - 242, 2025/04
2024年3月に開催された日本原子力学会2024年春の年会において、「遮蔽解析手法のV&V検討」研究専門委員会と放射線工学部会が「遮蔽解析のV&Vガイドライン策定に向けて」という合同セッションを開催した。会場では、3年間の委員会活動の概要報告が行われ、その後、V&V初期作業についてデータ開発、コード開発・許認可、国産データ・コード普及と維持の観点からそれぞれ講演いただいた。最後に、総合討論を通じて放射線遮蔽解析手法のV&V手順策定を進めるための情報交換が行われた。
大塚 直彦*; 多田 健一; Cabellos, O.*; 岩本 修
Annals of Nuclear Energy, 212, p.110977_1 - 110977_9, 2025/03
被引用回数：2 パーセンタイル：0.00(Nuclear Science & Technology)ロスアラモス国立研究所のLANCEにて測定された新しい
測定値を考慮して、3keVから1MeVの範囲のU-233の中性子捕獲断面積を評価した。得られた捕獲断面積は、JENDL-5の捕獲断面積よりも系統的に小さく、20keV付近では50%近く減少することとなった。新しく評価された断面積の妥当性を確認するため、ISCBEPハンドブックから選択された166の臨界実験を対象に、U-233の中性子捕獲断面積について、JENDL-5のデータを新たに評価した値に置き換えた上で、モンテカルロ中性子輸送計算を実行した。その結果、新しく評価された捕獲断面積の採用により、JENDL-5のU-233を用いた場合に比べてカイ2乗値がわずかに改善することが分かった。
岩本 修
日本原子力学会誌ATOMO, 67(2), p.103 - 107, 2025/02
核データライブラリは原子炉や加速器などの放射線が関わるシミュレーション計算の基盤となるものであり、現在の研究開発において不可欠な基盤データである。JENDLは日本で開発が進められてきた評価済核データライブラリであり、高速炉開発から始まる原子力を始めとする研究開発を支えてきた。2021年に公開した最新のJENDL-5は様々な放射線利用に対応するものであり、これまでのJENDLの集大成ともいえる充実したデータとなっている。多くの利用を通して今後のイノベーション創出へつながることを期待する。
岩本 修
JAEA-Conf 2024-002, p.41 - 46, 2024/11
The latest Japanese Evaluated Nuclear Data Library, JENDL-5, was released in 2021. JENDL-5 was developed with the amin of providing nuclear data to a wide range of application fields. JENDL-5 includes nuclear reaction data not only of neutron but also of proton, deuteron, alpha-particle, and photon. JENDL-5 also provides the data of thermal neutron scattering, fission product yields, and nuclear decay. These data were stored in separate sub-libraries; JENDL-5 consists of 11 sub-libraries. Regarding the neutron reaction data, the energy region was extended up to 200 MeV for 73 % of storing 795 target nuclei. The number of nuclei increased almost double of that of the previous version JENDL-4.0, covering most of the nuclei with the half-lives longer than 1 day. The revision of the data covered a wide range of nuclei from light to heavy ones reflecting the latest experimental data. The charged particle and photon induced reaction data were based on the data of the JENDL special purpose files released so far with revisions. JENDL-5 is expected to be applicable for large parts of computer simulations for radiations. For future, the covariance data in JENDL-5, whose updates and coverage are limited, will increase. Those data would be used to estimate reliability and uncertainties in the computer simulations originated from the nuclear data. The number of target nuclei of charged particle reaction data will also increase to satisfy future needs of wide area.
U(
) evaluated with the CCONE code system湊 太志*; 岩本 修
Physical Review C, 110(5), p.054311_1 - 054311_14, 2024/11
被引用回数：0 パーセンタイル：0.00(Physics, Nuclear)A calculation system with CCONE code is newly developed to estimate not only independent and cumulative fission fragment yields but also prompt fission neutron, prompt fission gamma, decay heats, and delayed neutrons simultaneously. This system enables us to study a correlation between various fission observables. To determine lots of parameters in this system efficiently, a Gaussian process and a least square fitting are adopted We tested the calculation system through a thermal neutron-induced fission on U. In this paper, we demonstrate the performance of the parameter search method and show that experimental fission fragment yield data and other observables resulting from fission are reproduced well by the new calculation system.
岩本 修; 岩本 信之; 多田 健一; 片渕 竜也*
核データニュース(インターネット), (139), p.1 - 7, 2024/10
OECD/NEA/NSCが主催するWPEC(Working Party on International Nuclear Data Evaluation Co-operation)の第36回会合、傘下の専門家グループ(EG)及びサブグループ(SG)会合が2024年5月13日から18日にNEA本部とオンラインのハイブリッド形式で開催された。日本からは岩本(修)が現地で参加し、岩本(信之)、多田、片渕がオンラインで参加した。核データの測定や評価及びEGやSGの活動報告、新SGの提案がなされた。これらの概要については報告する。
遠藤 駿典; 安部 亮太*; 藤岡 宏之*; 猪野 隆*; 岩本 修; 岩本 信之; 河村 しほり*; 木村 敦; 北口 雅暁*; 小林 龍珠*; et al.
European Physical Journal A, 60(8), p.166_1 - 166_10, 2024/08
被引用回数：2 パーセンタイル：74.11(Physics, Nuclear)Measurements of 
-ray circular polarization emitted from neutron capture reactions provide valuable information for nuclear physics studies. The spin and parity of excited states can be determined by measuring the circular polarization from polarized neutron capture reactions. Furthermore, the -ray circular polarization in a neutron capture resonance is crucial for studying the enhancement effect of parity nonconservation in compound nuclei. The -ray circular polarization can be measured using a polarimeter based on magnetic Compton scattering. A polarimeter was constructed, and its performance indicators were evaluated using a circularly polarized -ray beam. Furthermore, as a demonstration, the -ray circular polarization was measured in 
S(n,)
S reactions with polarized neutrons.
I and 
I using the NaI(Tl) spectrometer of the ANNRI beamline at J-PARCRovira Leveroni, G.; 木村 敦; 中村 詔司; 遠藤 駿典; 岩本 修; 岩本 信之; 藤 暢輔; 瀬川 麻里子; 前田 亮; 片渕 竜也*
European Physical Journal A, 60(5), p.120_1 - 120_14, 2024/05
被引用回数：0 パーセンタイル：0.00(Physics, Nuclear)The neutron capture cross section of I and I were measured from the thermal to the keV energy region with the NaI(Tl) spectrometer of the Accurate Neutron-Nucleus Reaction Measurement Instrument beamline in the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex. The neutron capture yield was determined by means of the total energy detection principle with the pulse-height weighting technique. The present cross section results for I were normalized using the saturated resonance method with a thick-enough 
Au and provide good agreement with JENDL-5 from thermal to about 500 keV. A resonance analysis with the REFIT code was performed and the resonance parameters for I below 310 eV are presented in this work. In the case of I, the three largest resonances of I were employed for the cross section normalization. The present results for I are the first experimental data for the neutron region between thermal and 20 eV. The present data display a different energy dependence than that in the JENDL-5 and JEFF-3.3 and much similar to that in ENDF/B-VIII.0. Notwithstanding, good agreement was found at the thermal region between the present measurement of 31.6 
1.3 b and both evaluated and most experimental data.
中山 梓介; 岩本 修; 木村 敦
EPJ Web of Conferences, 294, p.07001_1 - 07001_6, 2024/04
溶融塩炉などの革新型原子炉の減速材として黒鉛の利用が考えられている。減速材による熱中性子の散乱は炉心設計に大きな影響を与える。革新型原子炉の開発に貢献するため、原子炉級黒鉛の熱中性子散乱則の評価を行った。格子振動に起因する非弾性散乱成分は、第一原理シミュレーションから求めたフォノン状態密度に基づいて評価した。シミュレーションは理想的な結晶黒鉛に対して行った。結晶構造に起因する干渉性弾性散乱成分は、J-PARC/MLF施設で実施された中性子透過実験および散乱実験に基づいて評価した。中性子透過実験との比較においては、空孔などの結晶よりも大きな構造に起因する中性子小角散乱の定量が重要であることがわかった。以上の方法に基づいて、原子炉級黒鉛の熱中性子散乱則データを評価した。
Am neutron capture cross section measurement using the NaI(Tl) spectrometer of the ANNRI beamline of J-PARCRovira Leveroni, G.; 木村 敦; 中村 詔司; 遠藤 駿典; 岩本 修; 岩本 信之; 片渕 竜也*; 児玉 有*; 中野 秀仁*; 佐藤 八起*
Journal of Nuclear Science and Technology, 61(4), p.459 - 477, 2024/04
被引用回数：1 パーセンタイル：23.64(Nuclear Science & Technology)The neutron capture cross-section of Am was measured from 10 meV to about 1 MeV using the NaI(Tl) spectrometer of the Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) beamline in the Materials and Life Science (MLF) facility of the Japan Proton Accelerator Research Complex (J-PARC). The total energy detection principle was applied in conjunction with the pulse-height weighting technique to derive the neutron capture yield. The present cross-section results were normalized using a Au sample measurement by applying the saturated resonance method. The thermal cross section was measured to be 708 22 b, in agreement within uncertainties to the present evaluation in JENDL-5 of 709 b. Moreover, the results of a shape resonance analysis of the resolved resonance region are also provided in the present dissertation.
Ta遠藤 駿典; 木村 敦; 中村 詔司; 岩本 修; 岩本 信之; Rovira Leveroni, G.; 藤 暢輔; 瀬川 麻里子; 前田 亮
Nuclear Science and Engineering, 198(4), p.786 - 803, 2024/04
被引用回数：1 パーセンタイル：23.64(Nuclear Science & Technology)The neutron transmission ratio and capture yield for Ta were measured in J-PARC MLF ANNRI to improve the accuracy of resonance parameters. The total cross section was determined from the transmission ratio in the energy range from 0.2 to 150 eV. The capture cross section was obtained from the capture yield using the pulse height weighting technique (PHWT) in the energy range from thermal to 150 eV. The obtained transmission ratio and capture cross-section were fitted by the resonance analysis code, REFIT, and the resonance parameters were determined below 150 eV. It was also discussed the correlations caused by fitting based on statistical uncertainty and correlations for systematic uncertainty based on sample thickness in the transmission measurements.
I and I using ANNRI at MLF/J-PARCRovira Leveroni, G.; 木村 敦; 中村 詔司; 遠藤 駿典; 岩本 修; 岩本 信之; 藤 暢輔; 瀬川 麻里子; 前田 亮; 片渕 竜也*
JAEA-Conf 2023-001, p.74 - 79, 2024/02
Measurements to measure the neutron capture cross section of I and I were performed in the Accurate Neutron Nucleus Reaction Measurement Instrument (ANNRI) at the Materials and Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). The time-of-flight (TOF) methodology was employed to determine the neutron capture cross section from thermal to about 100 keV. The results from I were used to normalize the I cross section. Preliminary results of a resonance analysis below 100 eV for I are also presented.
奥山 莉子*; 大塚 直彦*; 千葉 豪*; 岩本 修
Journal of Nuclear Science and Technology, 61(1), p.57 - 67, 2024/01
被引用回数：2 パーセンタイル：23.64(Nuclear Science & Technology)The 
Pu neutron-induced fission cross section was evaluated from 100 keV to 200 MeV. The experimental Pu and U fission cross sections and their ratios in the EXFOR library were reviewed and analysed by the least-squares method. Additional simultaneous evaluation was performed by including the experimental database of the 
U and 
Pu fission cross sections and their ratios developed for JENDL-5 evaluation. The evaluated Pu fission cross section was verified against the cross section measured in the californium-252 spontaneous fission neutron field and criticalities of small-sized LANL fast systems. The newly evaluated fission cross section is systematically lower than the JENDL-4.0 cross section and demonstrates better performance.
La and evaluation of resonance parameters遠藤 駿典; 河村 しほり*; 奥平 琢也*; 吉川 大幹*; Rovira Leveroni, G.; 木村 敦; 中村 詔司; 岩本 修; 岩本 信之
European Physical Journal A, 59(12), p.288_1 - 288_12, 2023/12
被引用回数：2 パーセンタイル：43.87(Physics, Nuclear)ランタン(La)-139の断面積と共鳴パラメータは、原子力分野への応用や基礎核物理の研究にとって重要である。本論文では、大強度陽子加速器施設(J-PARC)のANNRIにてLaの中性子全断面積と捕獲断面積を測定した。Negative共鳴を含む4つの共鳴の共鳴パラメータを、共鳴解析コードREFITを用いて求めた。その結果いくつかの共鳴パラメータにおいて、評価済み核データライブラリとの不一致が見られた。さらに全断面積を再現するために、スピン依存する散乱半径もフィットした。得られた散乱半径は、評価済み核データライブラリで記録されたものよりも大きいことがわかった。
岩本 修; 岩本 信之; 木村 敦; 多田 健一; 横山 賢治
核データニュース(インターネット), (136), 6 Pages, 2023/10
OECD/NEA/NSC主催のWPEC(Working Party on International Nuclear Data Evaluation Co-operation)の本会合及び関連するサブグループ(SG)、専門家グループ(EG)会合が、2023年5月15日
5月17日の日程で、NEA本部とWebでのハイブリッド形式によって実施された。日本からは2名(岩本(修)、多田)が対面で、その他がオンラインで参加した。日本を含め、米国や欧州、中国、IAEA、NEAから出席があり、対面でのWPEC本会合への参加は30名程度であった。以下に、核データ測定、評価及びEG、SGの活動状況について報告する。
Gd and 
Gd in the thermal energy region with the Li-glass detectors and NaI(Tl) spectrometer installed in J-PARC
MLFANNRI木村 敦; 中村 詔司; 遠藤 駿典; Rovira Leveroni, G.; 岩本 修; 岩本 信之; 原田 秀郎; 片渕 竜也*; 寺田 和司*; 堀 順一*; et al.
Journal of Nuclear Science and Technology, 60(6), p.678 - 696, 2023/06
被引用回数：2 パーセンタイル：28.39(Nuclear Science & Technology)Neutron total and capture cross-section measurements of Gd and Gd were performed in the ANNRI at the MLF of the J-PARC. The neutron total cross sections were determined in the energy region from 5 to 100 meV. At the thermal neutron energy, the total cross sections were obtained to be 59.41.7 and 251.94.6 kilobarn for Gd and Gd, respectively. The neutron capture cross sections were determined in the energy region from 3.5 to 100 meV with an innovative method by taking the ratio of the detected capture event rate between thin and thick samples. At the thermal energy, the capture cross sections were obtained as 59.02.5 and 247.43.9 kilobarn for Gd and Gd, respectively. The present total and capture cross sections agree well within the standard deviations. The results for Gd were found to be consistent with the values in JENDL-4.0 and the experimental data given by Mastromarco et al. and Leinweber et al. within one standard deviation. Moreover, the present results for Gd agreed with the evaluated data in JENDL-4.0 and the experimental data by M
ller et al. within one standard deviation and agreed with the data by Mastromarco et al. within 1.4 standard deviations. However, they disagree (11% larger) with the experimental result by Leinweber et al.
Rovira Leveroni, G.; 木村 敦; 中村 詔司; 遠藤 駿典; 岩本 修; 岩本 信之; 片渕 竜也*; 児玉 有*; 中野 秀仁*; 堀 順一*; et al.
EPJ Web of Conferences, 284, p.06007_1 - 06007_4, 2023/05
被引用回数：0 パーセンタイル：0.00(Nuclear Science & Technology)A neutron filtering system has been installed at the ANNRI beamline in order to bypass the doublet structure of the incident neutron beam in the keV region. Thick cylindrical slabs of 
Fe, Si and Cr which share the characteristic of a sharp minimum in the neutron total cross section, were separately introduced in an intermediate stage of the beamline, before the NaI(Tl) spectrometer experimental area. The filtered neutron beams were analyzed by means of both neutron capture and transmission experiments. Moreover, further information about the neutron energy distribution within the filtered peaks was derived through the use of Monte-Carlo simulations with the PHITS code. The characteristics of the filtered neutron beams for Fe, i and Cr are presented together with Au standard experimental results to assess the performance of the neutron filtering system in neutron capture cross section experiments.
大塚 直彦*; 岩本 修
EPJ Web of Conferences, 284, p.08011_1 - 08011_4, 2023/05
被引用回数：4 パーセンタイル：91.39(Nuclear Science & Technology)The fast neutron fission cross sections of 
U and Pu were evaluated for the JENDL-5 library up to 200 MeV. The experimental fission cross sections and their ratios in the EXFOR library were reviewed with the source articles. Additionally, Poenitz's data compiled in his GMA database were reviewed. We found about 
0 datasets are archived with the uncertainty information sufficient for covariance matrix construction and converted them from EXFOR to an experimental database with their covariance matrices. When the uncertainty information in the source article is missing in the EXFOR entry, we updated the EXFOR entry. We minimized corrections to the experimental database to make our evaluation becomes traceable. The least-squares fitting was performed to the logarithms of the cross sections and their rations in the experimental database by using the simultaneous least-squares fitting code SOK. The best precisions of the group-wise cross sections were achieved around 2 to 3 MeV, where the external uncertainties are 1% (
U), 1.5% (
U, 
Pu) or 2.5% (Pu). Well documented experimental fission cross sections are desired for U between 100 and 300 keV and Pu in the whole energy range since the numbers of the usable experimental datasets are limited and it makes the uncertainties in our evaluation relatively high. The evaluated cross sections were also validated against the spectrum averaged fission cross sections measured under the 
Cf and - neutron fields, and we found the newly evaluated cross sections are consistent with the experimental spectrum averaged cross sections well except for 
U fission cross sections measured in the Cf neutron fields, which is underestimated by the newly evaluated cross sections as well as those in many other data libraries.
岩本 修; 岩本 信之; 国枝 賢; 湊 太志; 中山 梓介; 木村 敦; 中村 詔司; 遠藤 駿典; 長家 康展; 多田 健一; et al.
EPJ Web of Conferences, 284, p.14001_1 - 14001_7, 2023/05
被引用回数：2 パーセンタイル：84.55(Nuclear Science & Technology)Japanese Evaluated Nuclear Data Library version 5 (JENDL-5) was released in 2021. JENDL-5 is intended to extend its generality from JENDL-4.0 by covering a wide variety of nuclear data for applications not only to nuclear design and decommissioning, but also to radiation-related fields. Overview of JENDL-5 and a future plan for the next of JENDL-5 are presented. JENDL-5 includes up-to-date neutron reaction cross sections incorporating other various types of data such as newly evaluated nuclear decay, fission yield, and thermal neutron scattering law. The neutron induced reaction cross sections especially on minor actinides in the resonance regions are improved by the experimental data measured at ANNRI. The extensive benchmark analyses on neutron nuclear data were made and the performance of JENDL-5 was confirmed by benchmark tests of ICSBEP and IRPhEP as well as fast reactors, radiation shielding calculations, and so on. So far, several JENDL special-purpose files have been developed for various applications. The data cover neutron, charged particles, and photon induced reactions. As the neutron induced reaction files, two special purpose files of JENDL/AD-2017 and JENDL/ImPACT-2018 were released to meet needs of nuclear backend applications including activation evaluation for nuclear facilities and nuclear transmutations of high-level radioactive wastes of long-lived fission products, respectively. Furthermore, the photon, proton and deuteron data were released as JENDL/PD-2016.1, JENDL-4.0/HE and JENDL/DEU-2020, respectively, for accelerator applications. With updating the data, they were incorporated in JENDL-5 as sub-libraries for facilitation of usability of JENDL. As the next step of JENDL-5, provision of the proper and sufficient covariance will be a major challenge, where cross correlations across different reactions or data-types may play a significant role in connection with data assimilation for various applications.
