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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*
Annals of Nuclear Energy, 225, p.111688_1 - 111688_18, 2026/01
The neutron total and capture cross sections of
Er were measured at the Accurate Neutron-Nucleus Reaction Measurement Instrument beamline in the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex. For the neutron total cross-section measurements, Li-glass detectors were employed to derive the neutron transmission ratio of three
Er transmission samples with thicknesses of 1 mm, 0.175 mm and 0.05 mm. The neutron capture cross-section was determined from measurements of 0.025-mm-thick
Er samples with NaI(Tl) and Ge spectrometers in separate experiments, since they offer complementary capabilities. Moreover, the capture cross-section of
Er was derived below 1 eV, since it accounted for over 95% of the capture events in
Er. Finally, the resolved resonance region up to 65 eV was analyzed using the REFIT code. The resonance parameters of 20
Er resonances, together with one resonance for each
Er and
Er were determined in a least-square fit using a combination of both capture data and the transmission data from the thicker 1 mm and 0.175 mm samples. T
Hf(n,
)
Hf reaction measurement河村 しほり*; 遠藤 駿典; 岩本 修; 岩本 信之; 木村 敦; 北口 雅暁*; 中村 詔司; 奥平 琢也*; Rovira Leveroni, G.; 清水 裕彦*; et al.
EPJ Web of Conferences, 329, p.05002_1 - 05002_3, 2025/06
共鳴の全角運動量は低エネルギー核反応において重要なパラメータの一つである。実験から共鳴のJを推定する方法はいくつか提案されているが、本研究ではWetzelとThomasによって提案された、共鳴のガンマ線スペクトルにおいて、適切に選ばれた2つの低エネルギーガンマ線の強度比を比較する方法に着目した。この方法は、HuizengaとVandenboschによって提案されたスピンメモリー効果(SME)に基づいている。SMEとは、カスケード遷移において多くの中間励起準位が存在しても、初期の共鳴状態のスピン情報が残ることを意味する。強度比に現れるSMEの強さは、強度比の差から定量的に評価することができる。過去の測定結果から、原子番号Zがマジックナンバー(Z=50)付近でSMEが大きくなることが示唆されている。本研究ではZ=50から離れた元素である天然のHf(Z=72)を用いて、J-PARC・MLF・ANNRIにおいて中性子捕獲反応測定を行った。SMEの強さは、共鳴からの低エネルギー
線の強度比から決定された。その結果、Hf(Z=72)で観測されたSMEはTa(Z=73)よりも非常に大きいことがわかった。
-rays emitted from
S(n,
)
S reaction with polarized neutrons遠藤 駿典; 藤岡 宏之*; 井出 郁央*; 飯沼 昌隆*; 岩本 信之; 岩本 修; 亀田 健斗*; 河村 しほり*; 木村 敦; 北口 雅暁*; et al.
EPJ Web of Conferences, 329, p.05003_1 - 05003_3, 2025/06
共鳴の全角運動量は核データにおいて重要なパラメータの一つであるが、その測定は困難な場合が多く、測定で決定されていないことが多い。本研究では共鳴の全角運動量を偏極中性子照射により発生したガンマ線の円偏光度の測定により決定する手法の確立を目指している。円偏光どの測定を行うためのガンマ線ポラリメータを開発し、J-PARC・MLF・ANNRIに設置し、偏極中性子入射による
S(n,
)
S反応における5.4MeVガンマ線の円偏光度の測定を行った。この5.4MeVのガンマ線は50%円偏光していることが知られており、このガンマ線を用いてポラリメータの円偏光度への感度であるAnalyzing Powerを決定することが目的である。測定の結果1%程度の差が確認され、ANNRIにて初めて円偏光度の測定に成功した。
I neutron capture cross-section in the keV neutron regionRovira Leveroni, G.; 木村 敦; 中村 詔司; 遠藤 駿典; 岩本 修; 岩本 信之; 片渕 竜也*
Journal of Nuclear Science and Technology, 12 Pages, 2025/00
被引用回数:0 パーセンタイル:0.00The
I neutron capture cross-section was measured at 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 obtain accurate results in the keV neutron region, the recently developed neutron filtering technique was employed with a 20-cm-thick
Si filter to tailor the incident neutron flux into quasi-monoenergetic neutron peaks with averaged neutron energies of 51.5 and 127.7 keV and, at the same time, hugely increase the signal-to-noise ratio. The present cross-section results were determined form the capture yield ratio of
I to that of
Au and using the evaluated nuclear data from JENDL-5 as reference. The
I neutron capture cross section was found to be 0.278
0.034 b at 51.5 keV and 0.141
0.015 b 127.7 keV, validating the JENDL-5 and JEFF-3.3 evaluations, as well as the results from Noguere et al., in contrast to the larger evaluations of JENDL-4.0 and ENDF/B-VIII.1 and the data from Macklin et al.
Er at ANNRIRovira Leveroni, G.; 木村 敦; 中村 詔司; 遠藤 駿典; 岩本 修; 岩本 信之; 片渕 竜也*
JAEA-Conf 2024-002, p.127 - 132, 2024/11
Measurements to measure the total and neutron capture cross section of
Er 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). In this study, the preliminary results for the
Er neutron total and capture cross sections measured with Li-glass, Ge and NaI(Tl) detectors are presented and compared.
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:3 パーセンタイル:67.20(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:2 パーセンタイル:54.52(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.
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:2 パーセンタイル:33.46(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:16.48(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.
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:34.66(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。
Gd and
Gd in the thermal energy region with the Li-glass detectors and NaI(Tl) spectrometer installed in J-PARC
MLF
ANNRI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:3 パーセンタイル:45.16(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 251.9
4.6 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 59.0
2.5 and 247.4
3.9 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.
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:81.71(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.
Am neutron capture cross section in the keV region using Si and Fe-filtered neutron beamsRovira 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*
Journal of Nuclear Science and Technology, 60(5), p.489 - 499, 2023/05
被引用回数:4 パーセンタイル:45.16(Nuclear Science & Technology)The neutron capture cross-section of
Am was measured in the keV neutron range using the recently implemented neutron filtering system 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). Filter arrays consisting of 20 cm of
Fe and
Si were employed in separate measurements to provide filtered neutron beams with averaged neutron energies of 23.5 (Fe), 51.5 and 127.7 (Si) keV. The present
Am results were obtained relative to the
Au neutron capture yield by applying the total energy detection principle together with the pulse-height weighting technique. The
Am neutron capture cross section was determined as 2.72
0.29 b at 23.5 keV, 2.14
0.26 b at 51.5 keV and 1.32
0.10 b at 127.7 keV with total uncertainties in the range of 8 to 12
, much lower in comparison to the latest time-of-flight experimental data available.
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.
遠藤 駿典; 木村 敦; 中村 詔司; 岩本 修; 岩本 信之; Rovira Leveroni, G.
EPJ Web of Conferences, 281, p.00012_1 - 00012_5, 2023/03
In resonance analysis, experimental uncertainties affect the accuracy of resonance parameters. A resonance analysis code REFIT can consider the statistical uncertainty of the experimental data in evaluation of the resonance parameter uncertainty. On the other hand, since the systematic uncertainties of the sample thickness and normalization, which is proportional to the cross-section, are not independent at each measurement point, they must be treated differently from the statistical uncertainty. However, their treatment has not been discussed in detail so far. In this study, we evaluated the effect of the systematic uncertainties of experimental data on deduced resonance parameters by varying sample-thickness values used for the REFIT code. Covariance of resonance parameters ascribed to systematic uncertainties were evaluated from the neutron transmission data of natural zinc measured at the J-PARC MLF ANNRI. We will introduce this evaluation method and discuss the feature of obtained correlations.
Ta(n,
)
Ta reaction河村 しほり*; 遠藤 駿典; 岩本 修; 岩本 信之; 木村 敦; 北口 雅暁*; 中村 詔司; 奥平 琢也*; Rovira Leveroni, G.; 清水 裕彦*; et al.
JAEA-Conf 2023-001, p.115 - 120, 2023/02
複合核共鳴における全角運動量は、核データを構成する1つの重要なパラメータである。しかしながら直接的な測定は、核編極標的を用いる必要があるなど難しい場合が多く、核データとして整備された値はランダムに割り振られた推定値であることが多い。本研究では共鳴から放出される複数のガンマ線のうち、2つの低エネルギーガンマ線の強度比を取る手法を用いて、実験結果に基づき
Taの共鳴の全角運動量を推定した。実験はJ-PARC・MLF・ANNRIにて、Ge検出器を用いて行った。本発表では実験・解析の詳細および既存の核データの値や先行研究との比較について報告を行う。
Am neutron capture cross section measurement and resonance analysisRovira 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*
JAEA-Conf 2022-001, p.91 - 96, 2022/11
Neutron capture cross section measurements 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 in a non-filter condition experiment to determine the neutron capture cross section from thermal to about 100 eV. Moreover, experiments were performed using the neutron filtering system to determine the neutron capture cross section at the energy of 23.5 keV using Fe as filter material. In this study, the preliminary results of the
Am neutron capture cross section from 10 meV to about 100 eV determined in TOF experiments and at 23.5 keV from Fe filter experiments are presented. In the TOF experiments, the
Am neutron capture cross section was normalized by means of the saturated resonance method using a Au sample with a mass of 1.5 g. In addition, for the Fe filter experiments, the capture cross section of
Am at the energy of 23.5 keV was determined relative to the
Au yield obtained from a measurement using the same Au sample. Moreover, early-stage results of a resonance analysis of the
Am capture resonances are also presented.
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:2 パーセンタイル:17.30(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.