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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：35.75(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 59.4
1.7 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.
片渕 竜也*; 岩本 修; 堀 順一*; 木村 敦; 岩本 信之; 中村 詔司; Rovira Leveroni, G.; 遠藤 駿典; 芝原 雄司*; 寺田 和司*; et al.
EPJ Web of Conferences, 281, p.00014_1 - 00014_4, 2023/03
Long-lived minor actinides (MA) in nuclear waste from nuclear power plants are a long-standing issue to continue nuclear energy production. To solve the issue, researchers have suggested nuclear transmutation, in which long-lived radionuclides are transmuted into stable or shorter-life nuclides via neutron-induced nuclear reactions. Development of nuclear transmutation systems as an accelerator-driven system requires accurate neutron nuclear reaction data. The present research project entitled "Study on accuracy improvement of fast-neutron capture reaction data of long-lived MAs for development of nuclear transmutation systems" have been conducted as a joint collaboration, including Tokyo Tech, Japan Atomic Energy Agency and Kyoto University. This project focuses on the neutron capture reaction of MAs, especially 
Np, 
Am and 
Am, in the fast neutron energy region. The final goal of this project is to improve the accuracies of the neutron capture cross sections of Np, Am and Am employing a high-intensity neutron beam from a spallation source of the Japan Proton Accelerator Research Complex (J-PARC) that reduces uncertainties of measurement. To achieve the goal, a neutron beam filter system in J-PARC, sample characteristic assay, and theoretical reaction model study were developed. In this contribution, the overview and results of the project will be presented.
中野 秀仁*; 片渕 竜也*; Rovira Leveroni, G.; 児玉 有*; 寺田 和司*; 木村 敦; 中村 詔司; 遠藤 駿典
Journal of Nuclear Science and Technology, 59(12), p.1499 - 1506, 2022/12
被引用回数：2 パーセンタイル：35.75(Nuclear Science & Technology)A neutron monitoring detection system was developed for neutron capture cross section measurement using a spallation neutron source. A combination of a plastic scintillator and a thin 
LiF foil was adopted for the detector. The detector system was tested to study the feasibility of the system. Neutron irradiation experiments were conducted with the Accurate Neutron-Nucleus Reaction Measurement Instrument in the Materials and Life Science facility of the Japan Proton Accelerator Research Complex. A neutron time-of-flight spectrum was successfully measured without significant count loss or detector paralysis. The statistical uncertainty reached 0.7% at neutron energies around 6 meV.
Au with a Cr-filtered neutron beam at the ANNRI beamline of MLF/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*; et al.
Journal of Nuclear Science and Technology, 59(5), p.647 - 655, 2022/05
被引用回数：1 パーセンタイル：11.62(Nuclear Science & Technology)Cr-filtered keV-neutron experiments were performed in 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) to measure the neutron capture cross-section of Au. The energy range of the neutron filtering system at ANNRI was extended through the use of 15 cm of 
Cr as filter material to tailor quasi-monochromatic neutron peaks with averaged neutron energies of 133.4 and 45.0 keV. The performance of the Cr filter assembly was evaluated by means of experimental capture and transmission analyses, together with the use of Monte-Carlo simulations. The present Au neutron capture cross-section results provide agreement within uncertainties with the JENDL-4.0 standard evaluated library and the IAEA standard data library further demonstrating the capabilities of the neutron filtering system at ANNRI.
Rovira Leveroni, G.; 岩本 修; 木村 敦; 中村 詔司; 岩本 信之; 遠藤 駿典; 片渕 竜也*; 寺田 和司*; 児玉 有*; 中野 秀仁*; et al.
JAEA-Conf 2021-001, p.156 - 161, 2022/03
A neutron filtering system has been designed in order to bypass the double-timed structure of the beam. Filter materials were introduced into the rotary collimator of the ANNRI beamline in order to produce quasi-monoenergetic neutron filtered beams. Filter assemblies consisting of Fe with a thickness of 20 cm, and Si with thicknesses of 20 cm and 30 cm of Si were used separately to produce filtered neutron peaks with energies of 24 keV (Fe) and of 54 and 144 (Si). In this study, the characteristics and performance of the neutron filtering system at ANNRI using Fe and Si determined from both measurements and simulations are presented. The incident neutron flux was tested and analyzed by means of transmission and capture experiments. Moreover, simulations using the PHITS code were performed in order to determine the energy distribution of the integrated filtered peaks and assess the reliability of experimental results. Finally, preliminary results of the capture cross section of Au at the filtered energies of 24, 54 and 144 keV are also presented using the NaI(Tl) spectrometer alongside the neutron filtering system.
児玉 有*; 片渕 竜也*; Rovira Leveroni, G.; 中野 秀仁*; 寺田 和司*; 木村 敦; 中村 詔司; 遠藤 駿典
JAEA-Conf 2021-001, p.162 - 165, 2022/03
Precise nuclear data for neutron-induced reactions are necessary for the design of nuclear transmutation systems. Nevertheless, current uncertainties of nuclear data for minor actinide (MA) does not achieve requirements for the design of transmutation facilities. The determination of an incident neutron flux for measurements of neutron capture cross section is one of the main causes that affect the final uncertainty of the cross section results. In the present work, we suggest a new method to reduce systematic uncertainties of capture cross section measurements. The method employs change of the self-shielding effect with sample rotation angle. In capture cross section measurements in ANNRI, a boron sample is placed to determine the incident neutron spectrum by counting 478 keV 
-ray from the 
reaction. In this method, the boron sample is tilted with respect to the neutron beam direction, thereby changing the effective area. This results in change of the shapes of time-of-flight (TOF) spectrum of 478 keV -ray from the reaction with the tilted angle. Comparing the difference of the TOF spectra at different angles and assuming the 1/v energy dependence of cross section of the reaction, the area density of the boron sample can be determined without using the sample mass and area. Theoretical and experimental studies on the new method are ongoing. Calculation using Monte Carlo simulation code PHITS were carried out to study the feasibility of the present method. Test experiments using a sample rotation system at ANNRI were also performed.
中野 秀仁*; 片渕 竜也*; Rovira Leveroni, G.*; 児玉 有*; 寺田 和司*; 木村 敦; 中村 詔司; 遠藤 駿典
JAEA-Conf 2021-001, p.166 - 170, 2022/03
In neutron capture cross section measurement, monitoring the number of the incident neutrons is necessary. However, in measurement with J-PARC/ANNRI, direct neutron monitoring system has not been employed. Conventional neutron detectors cannot be used as a beam monitor at ANNRI because of two reasons, high counting rate environment and gamma-flash. In general, a semiconductor detector or an inorganic scintillator, which is adopted for a neutron detector, has relatively longer response time and is unsuitable for beam monitoring at ANNRI. Therefore, a combination of a thin plastic scintillator and a LiF foil was selected as a detection system, whose fast response enabled detecting neutrons at a high counting rate. Low gamma ray sensitivity of a thin plastic scintillator allows measuring fast TOF region without count loss or detector paralysis. The geometry of the LiF foil, the plastic scintillator, and photomultiplier tube (PMT) was designed. The optimal thickness of the LiF foil was determined with simulation codes, SRIM and PHITS. The detector system was tested under the high neutron irradiation condition at J-PARC /ANNRI. A neutron TOF spectrum was successfully measured without significant count loss or detector paralysis. A neutron energy spectrum was driven from difference of TOF spectrum with and without LiF. The neutron spectrum was compared with a past neutron spectrum and good agreement was obtained. Statistic error was 0.68 
at 6.0 meV even though measurement times in this study were short.
Am around 23.5 keV児玉 有*; 片渕 竜也*; Rovira Leveroni, G.; 木村 敦; 中村 詔司; 遠藤 駿典; 岩本 信之; 岩本 修; 堀 順一*; 芝原 雄司*; et al.
Journal of Nuclear Science and Technology, 58(11), p.1159 - 1164, 2021/11
被引用回数：4 パーセンタイル：45.28(Nuclear Science & Technology)The neutron capture cross section of Am was measured with a pulsed neutron beam from a spallation neutron source of the Japan Proton Accelerator Research Complex. A Fe neutron beam filter was used to make the incident neutron beam mono-energetic around 23.5 keV. The neutron capture -rays were detected with a NaI(Tl) detector. The pulse height weighting technique was employed to derive the neutron capture cross section from the pulse height spectrum. The cross section was determined relative to the capture cross section of Au of JENDL-4.0. The neutron capture cross section of Am was determined with a smaller uncertainty than previous measurements. The previous measurements and the JENDL-4.0 cross sections were found to be lower than the present result.
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*; 寺田 和司*; 児玉 有*; 中野 秀仁*; et al.
Nuclear Instruments and Methods in Physics Research A, 1003, p.165318_1 - 165318_10, 2021/07
被引用回数：5 パーセンタイル：56.17(Instruments & Instrumentation)A neutron filtering system has been introduced in the Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) beamline in the Material and Life Science (MLF) building of the Japan Proton Accelerator Research Complex (J-PARC) in order to produce quasi-monoenergetic neutron beams. The filtered neutron spectrum by the filter assemblies was analyzed by means of capture and transmission measurements and also by Monte Carlo simulations using PHITS. The characteristics of the filtered neutron beam are discussed alongside its viability in future applications for neutron cross-section measurements in the fast neutron region.
Y片渕 竜也*; 藤 暢輔; 水本 元治*; 齋藤 辰宏*; 寺田 和司*; 木村 敦; 中村 詔司; Huang, M.*; Rovira Leveroni, G.; 井頭 政之*
European Physical Journal A, 57(1), p.4_1 - 4_4, 2021/01
被引用回数：4 パーセンタイル：48.14(Physics, Nuclear)A new neutron resonance of Y was found in time-of-flight (TOF) neutron capture experiments using a pulsed neutron beam from a spallation neutron source of the Japan Proton Accelerator Research Complex. The observed resonance energy was 19.7 eV that is much lower than the lowest energy (2.60 keV) of the previous reported resonances. In addition to the TOF measurement, nuclide identification of the resonance was made by prompt -ray analysis. Neutron capture -rays from Y were clearly observed only on the resonance. Resonance analysis was applied to the experimental results and the resonance parameters of the new resonance are given.
片渕 竜也*; 堀 順一*; 岩本 信之; 岩本 修; 木村 敦; 中村 詔司; 芝原 雄司*; 寺田 和司*; 登坂 健一*; 遠藤 駿典; et al.
JAEA-Conf 2020-001, p.5 - 9, 2020/12
A research project entitled "Study on accuracy improvement of fast-neutron capture reaction data of long-lived MAs for development of nuclear transmutation systems" has been ongoing since 2017. The project aims at improving accuracy of neutron capture cross sections of long-lived minor actinides (MAs; Np and 
Am) in the fast neutron energy region which are very important for development of nuclear transmutation systems. In order to improve the capture reaction data of MAs, measurements using an intense pulsed neutron beam from a spallation neutron source of J-PARC are planned. The project consists of four parts: (1) development of neutron beam filter system, (2) cross section measurement, (3) sample characteristic assay, and (4) theoretical study. The filter system is designed to solve a double bunch issue in J-PARC. The sample characteristic assay lowers systematic uncertainties originating the samples. In the theoretical study, a nuclear reaction model is applied to analyzing cross sections and -ray spectra measured in experiments. The outline of the project and the current progress will be presented.
片渕 竜也*; 岩本 修; 堀 順一*; 木村 敦; 岩本 信之; 中村 詔司; 芝原 雄司*; 寺田 和司*; Rovira, G.*; 松浦 翔太*
EPJ Web of Conferences, 239, p.01044_1 - 01044_4, 2020/09
被引用回数：2 パーセンタイル：82.33(Nuclear Science & Technology)In 2017, a research project entitled "Study on accuracy improvement of fast-neutron capture reaction data of long-lived MAs for development of nuclear transmutation systems" started as a joint collaboration, including Tokyo Tech, Japan Atomic Energy Agency and Kyoto University. This project focuses on neutron capture reaction of MAs, especially Np, Am and Am, in the fast neutron energy region. The final goal of this project is to improve the neutron capture cross sections of Np, Am and Am employing a high-intensity neutron beam from a spallation source of the Japan Proton Accelerator Research Complex (J-PARC) that reduces uncertainties of measurement. In this contribution, the overview of the project and the current progress will be presented.
NpRovira, G.*; 片渕 竜也*; 登坂 健一*; 松浦 翔太*; 寺田 和司*; 岩本 修; 木村 敦; 中村 詔司; 岩本 信之; 瀬川 麻里子; et al.
Journal of Nuclear Science and Technology, 57(1), p.24 - 39, 2020/01
被引用回数：12 パーセンタイル：78.39(Nuclear Science & Technology)The neutron capture cross-section of Np has been measured in the neutron energy region of 10 meV to 500 eV. A neutron time-of-flight method was employed using the NaI(Tl) spectrometer in the ANNRI beam-line at the Japanese Proton Accelerator Re-search Complex (J-PARC). The experimental capture yield was derived using the pulse-height weighting technique and an energy dependent cross-section was obtained relative to the incident neutron spectrum derived from a 
B(n, 
)
Li reaction yield. The absolute cross-section was determined by normalizing the results to JENDL-4.0 cross-section data at the first resonance of Np. The thermal cross-section was measured to be 177.6 3.8 b. The resolved resonance region was analyzed with the REFIT code.
片渕 竜也*; 岩本 修; 堀 順一*; 岩本 信之; 木村 敦; 中村 詔司; 芝原 雄司*; 寺田 和司*
JAEA-Conf 2019-001, p.193 - 197, 2019/11
A research project entitled "Study on improvement of neutron capture reaction data accuracies of long-lived minor actinides in fast neutron energy region for development of nuclear transmutation systems" started in 2017. The project aims at improving accuracies of neutron capture cross section of long-lived minor actinides (Np, Am, Am) in the fast neutron energy region which are very important for development of nuclear transmutation systems. In order to improve the capture reaction data of MA, measurement using an intense pulsed neutron beam from a spallation neutron source of the Japan Proton Accelerator Research Complex (J-PARC) is planned. The neutron beam filter is designed to solve the so-called double bunch issue of a neutron beam in J-PARC. This allows for measuring neutron capture cross sections using the high-intensity neutron beam of J-PARC. The outline of the project and the current progress will be presented.
Am neutron capture and total cross sections with ANNRI at J-PARC木村 敦; 中村 詔司; 寺田 和司*; 中尾 太郎*; 水山 一仁*; 岩本 信之; 岩本 修; 原田 秀郎; 片渕 竜也*; 井頭 政之*; et al.
Journal of Nuclear Science and Technology, 56(6), p.479 - 492, 2019/06
被引用回数：15 パーセンタイル：81.98(Nuclear Science & Technology)Neutron total and capture cross sections of Am have been measured in Accurate Neutron Nucleus Reaction measurement Instrument at Materials and Life Science Experimental Facility of Japan Proton Accelerator Research Complex with a neutron TOF method. The neutron capture cross section in the energy region from 10 meV to 100 eV was determined using an array of Ge detectors. Three samples with different activities were used for measurements of the capture cross section. The neutron total cross section in the energy region from 4 meV to 100 eV was measured using Li-glass detectors. Derived cross-section value at neutron energy of 0.0253 eV is 87.75.4 b for the capture cross section and 10111 b for the total cross section.
Am with ANNRI at J-PARC寺田 和司*; 木村 敦; 中尾 太郎*; 中村 詔司; 水山 一仁*; 岩本 信之; 岩本 修; 原田 秀郎; 片渕 竜也*; 井頭 政之*; et al.
Journal of Nuclear Science and Technology, 55(10), p.1198 - 1211, 2018/10
被引用回数：18 パーセンタイル：85.04(Nuclear Science & Technology)Neutron total and capture cross sections of Am have been measured with a new data acquisition system and a new neutron transmission measurement system installed in Accurate Neutron Nucleus Reaction measurement Instrument (ANNRI) at Materials and Life Science Experimental Facility (MLF) of Japan Proton Accelerator Research Complex (J-PARC). The neutron total cross sections of Am were determined by using a neutron time-of-flight method in the neutron energy region from 4 meV to 2 eV. The thermal total cross section of Am was derived with an uncertainty of 2.9%. A pulse-height weighting technique was applied to determine neutron capture yields of Am. The neutron capture cross sections were determined by the time-of-flight method in the neutron energy region from the thermal to 100 eV, and the thermal capture cross section was obtained with an uncertainty of 4.1%. The evaluation data of JENDL-4.0 and JEFF-3.2 were compared with the present results.
原田 秀郎; 岩本 修; 岩本 信之; 木村 敦; 寺田 和司; 中尾 太郎; 中村 詔司; 水山 一仁; 井頭 政之*; 片渕 竜也*; et al.
EPJ Web of Conferences, 146, p.11001_1 - 11001_6, 2017/09
被引用回数：2 パーセンタイル：76.20(Nuclear Science & Technology)A nuclear data project entitled Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides (AIMAC) is being performed in Japan. The objective of the project is to improve accuracy of neutron nuclear data for minor actinides and some fission products, which is required for developing innovative nuclear system transmuting these nuclei. Following research items have been conducted to achieve the objective: (1) Measurements of thermal neutron capture cross-sections by activation methods, (2) High-precision quantifications of shielded sample amounts used for TOF measurement, (3) Resonance parameter determinations at J-PARC/ANNRI and KURRI/LINAC, (4) Extension of capture cross sections to high energy neutrons at J-PARC/ANNRI, (5) High quality evaluation based on iterative communication with experimenters. The achievement of the project is presented.
中尾 太郎; 寺田 和司; 木村 敦; 中村 詔司; 岩本 修; 原田 秀郎; 片渕 竜也*; 井頭 政之*; 堀 順一*
EPJ Web of Conferences, 146, p.03021_1 - 03021_4, 2017/09
被引用回数：7 パーセンタイル：95.73(Nuclear Science & Technology)J-PARC物質・生命科学実験施設ANNRIビームラインのデータ収集系更新作業が行われた。MLFのビームパワーは2008年に比較して2015年には20倍以上となり、ビーム量の増大によりビームラインユーザーはより高統計の実験データを取得できるようになった。ビームパワー増大に対応するため、ANNRIにおけるGe検出器アレイのデータ収集システムが更新された。データ収集システムは同時に、中性子全断面積測定のために整備されているLi glass検出器の信号取得のためにも用いられる予定である。コミッショニング実験が0.1mm厚の金サンプルを用いてJ-PARCの500kW陽子ビームを用いて行われた。捕獲断面積および全断面積測定両方について飛行時間法の適用性が試験された。Ge検出器アレイについて、ADCおよびTDCの非線形性、エネルギー分解能、多チャンネルコインシデンスおよび不感時間の性能が測定された。Ge検出器の不感時間は従来のデータ収集システムに比較して、少しのエネルギー分解能劣化を許容すれば1/4になっていた。
-ray emission probabilities寺田 和司; 中村 詔司; 木村 敦; 中尾 太郎; 原田 秀郎; 片渕 竜也*; 井頭 政之*; 堀 順一*
JAEA-Conf 2016-004, p.21 - 25, 2016/09
マイナーアクチニドの中性子捕獲断面積の高精度化のためには、系統誤差に係ってくるサンプル量を高精度で決定することが重要である。原子力システム研究開発事業「マイナーアクチニドの中性子核データ精度向上に係る研究開発」の一環として、Am, 
Np及び
Paの線放出率の高精度測定を実施した。試料の放射能はアルファ線測定によって決定し、試料から放出される線をプレナ型Ge検出器で測定した。Ge検出器の検出効率は、標準線源の測定とPHITSを用いた線のモンテカルロシミュレーションを組み合わせて決定した。最終的に、これらの核種の線放出率を2%以内の精度で得ることができた。
中尾 太郎; 中村 詔司; 寺田 和司; 木村 敦; 原田 秀郎; 井頭 政之*; 片渕 竜也*; 堀 順一*
JAEA-Conf 2015-003, p.303 - 306, 2016/03
中性子捕獲の断面積測定には測定試料の絶対量が必要であるが、入手する試料は必ずしも絶対量が精度よく決定されていない。そのため、試料の絶対量を非破壊で、高精度に決定する必要がある。本発表では原子力システム研究開発事業「マイナーアクチニドの中性子核データ精度向上に係る研究開発」の一環として、中性子捕獲断面積高精度決定のために、測定試料となるマイナーアクチニドの絶対量を非破壊で測定しうる放出熱測定の計画について、特にRI特有の放射線遮蔽問題の観点から報告する。また、Am 線標準線源を用いたベンチマークテスト測定の結果も併せて報告する。
