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Rossi, F.; Lee, J.; 吉見 優希*; 弘中 浩太; 芝 知宙; 寺田 和司*; 堀 順一*
KURNS Progress Report 2025, P. 97, 2026/06
The ISCN of the JAEA is developing a combined neutron resonance analysis (NRA) system aims to identify and quantify fissile material in an unknown sample. Neutron resonance transmission analysis (NRTA) and neutron resonance capture analysis (NRCA) are used together with the proposed neutron resonance fission neutron analysis (NRFNA). Using a pulsed neutron beam with the neutron time-of-flight (TOF) technique, prompt capture gamma rays and fast fission neutrons from fissile nuclides are measured at the sample location with plastic scintillators able to perform n/g pulse shape discrimination (PSD). In this paper, we report a demonstration experiment for highly enriched uranium samples performed at KURNS-LINAC. This work is supported by MEXT under the subsidy for the "promotion for strengthening nuclear security and the like".
system社本 真一*; 安井 幸夫*; 吉澤 香奈子*; 野田 幸男*; 高橋 美和子*; 大貫 惇睦*; 芳賀 芳範; 石角 元志*; 山内 宏樹; Huang, T.-C.*; et al.
Physical Review B, 113(23), p.235126_1 - 235126_7, 2026/06
被引用回数：0
-Mn shows a large Sommerfeld constant 
of 70 mJ,
,Mn
,,K
, which is one of the largest values in 3-electron systems. Although the origin has been attributed to the fluctuating magnetic moment, there are no material-dependent systematic studies in the 3-electron systems except for doped -Mn. The ordered -Mn structure compounds Mn
TX (T = Co, Rh, Ir; X = Si, Ge) also exhibit the enhancement. We have studied the enhancement in MnTX system. The enhancement has been often accompanied with magnetic short-range order. The mechanism of the magnetic short-range order is discussed based on the phase diagrams of MnTX system. The phase diagrams are categorized in two groups. One group of MnCoSi and MnRhSi exhibits the magnetic short-range order above the N
el temperature, whereas the others do not. The two groups can be separated by the spin-orbit coupling value, regardless of the cubic lattice parameter.
Glazyrin, K.*; Spektor, K.*; Bykov, M.*; Carvalho, P. H. B.*; Dong, W.*; K
rmann, F.*; 佐野 亜沙美; 服部 高典; Beyer, D. C.*; Sahlberg, M.*; et al.
Nature Communications (Internet), 17, p.2622_1 - 2622_10, 2026/03
被引用回数：2 パーセンタイル：83.76(Multidisciplinary Sciences)高エントロピー材料の研究は様々な科学分野に貢献し、応用面で興味深い特性を次々と明らかにしている。本研究では、高温高圧下におけるX線・中性子飛行時間法実験および第一原理計算により、カンター合金(CoCrFeNiMn)の水素抵抗性を調査した。我々は、カンター合金組成に基づく面心立方(fcc)型水素化物の形成を報告する。さらに、水素含有量の推定を含むその特性評価を提供する。これらの知見は、高エントロピー合金および高エントロピー水素化物の複雑な化学に関する知見の蓄積に貢献するものである。
Rossi, F.; Lee, J.; 吉見 優希*; 芝 知宙; 寺田 和司*; 堀 順一*
第46回日本核物質管理学会年次大会会議論文集(インターネット), 4 Pages, 2025/12
The Japan Atomic Energy Agency is developing a non-destructive system to detect fissile nuclear materials within a sample combining resonance analysis from prompt fission neutrons, capture gamma-rays, and transmitted neutrons. The detection setup includes an array of plastic scintillators at the sample and a downstream 
Li scintillator. Recent improvements focus on better neutron/gamma discrimination using advanced EJ-276D plastic scintillators and optimized pulse shape discrimination analysis. Tests were conducted at the Kyoto University time-of-flight facility with natural and enriched uranium samples. This paper presents the latest design updates and experimental results from the system's development. This work is supported by MEXT under the subsidy for the "promotion for strengthening nuclear security and the like".
Rossi, F.; Lee, J.; 吉見 優希*; 弘中 浩太; 小泉 光生; 芝 知宙; 寺田 和司*; 堀 順一*
ESARDA Bulletin, (67), p.59 - 67, 2025/12
ISCN is developing an advanced neutron resonance analysis system for the identification and quantification of fissile materials. This system integrates three complementary techniques: NRTA, NRCA, and NRFNA, enabling simultaneous detection and improving sensitivity for fissile material identification. To evaluate the system's performance, we conducted a series of experiments using natural uranium samples with a thickness from 1.5 to 6.0 mm enclosed in a 2 cm thick box made of lead. The results show that even if the presence of lead generates significant background noise due to neutron scattering and reflection, a clear identification of 
U signatures is possible. These findings highlight the system's versatility and effectiveness in shielding scenarios, offering a promising tool for nuclear security and nonproliferation applications. By enabling concurrent measurements, the system improves accuracy and provides an innovative method for enhancing regulatory and safeguard efforts in the nuclear industry. This work is supported by MEXT under the subsidy for the "promotion for strengthening nuclear security and the like".
/graphene/yttrium iron garnet quadruple heterostructuresChoi, J. W.*; 吉川 貴史; Lee, S.-K.*; 他13名*
Journal of Materials Chemistry A, 13(32), p.26690 - 26699, 2025/08
被引用回数：1 パーセンタイル：0.00(Chemistry, Physical)Strong spin-orbit coupling (SOC) materials and graphene have recently emerged as promising interfacial layers for tailoring spin transport in normal metal/ferromagnet heterostructures. However, spin-to-charge conversion in Pt/two-dimensional (2D) layer/graphene/yttrium iron garnet (YIG) heterostructures remains experimentally unexplored. This study investigates the effects of monolayer graphene and its interfacial coupling with a non-magnetic 2D transition metal dichalcogenide (TMDC) with relatively strong SOC on the longitudinal spin Seebeck effect (LSSE) in Pt/TiSe (or ZrSe)/graphene/YIG quadruple heterostructures. Interfacial SOC between TMDC and graphene is demonstrated to induce an additional spin-to-charge conversion channel in the Pt layer, generating a charge current opposite in direction to the conventional inverse spin Hall effect-induced current from YIG and thereby leading to a net suppression of the LSSE signal. Thus, the study highlights the potential of non-magnetic TMDC interlayers for modulating spin transport, offering new design pathways for spintronic devices.
ders band-assisted high uniform ductility in ultrastrong ferrous medium-entropy alloy via hierarchical microstructureKwon, H.*; Lee, J. H.*; Zargaran, A.*; Harjo, S.; Gong, W.; Wang, J.*; Gu, G. H.*; Lee, B.-J.*; Bae, J. W.*; Kim, H. S.*
International Journal of Plasticity, 190, p.104378_1 - 104378_18, 2025/07
被引用回数：11 パーセンタイル：95.64(Engineering, Mechanical)In this work, we harness a hierarchical microstructure to simultaneously tailor strengthening and deformation mechanisms in a Co
Cr
Fe
Ni
Mo
(at%) ferrous medium-entropy alloy (MEA). A simple thermomechanical process (cold rolling and 90 s annealing) produces ultrafine recrystallized grains, non-recrystallized grains with substructures, and intragranular nanoprecipitates. This structure, with high dislocation density and fine grains, yields a high strength of 
1.60 GPa but can risk premature fracture. To overcome this, Lders deformation, enabled by ultrafine grain boundaries and stress-induced martensitic transformation at pre-existing nucleation sites, is employed. Stable Lders band propagation delays strain hardening and enables large uniform ductility. As a result, a tensile strength of 1.84 GPa and uniform elongation of 20% are achieved, matching the best tensile properties among reported multi-principal element alloys.
Kim, Y. S.*; Kang, T.*; Hong, S.-K.*; Brechtl, J.*; Lebyodkin, M.*; Cheng, Y.-H.*; Huang, E.-W.*; Liaw, P. K.*; Harjo, S.; Gong, W.; et al.
Acta Materialia, 292, p.120970_1 - 120970_16, 2025/06
被引用回数：14 パーセンタイル：95.77(Materials Science, Multidisciplinary)Metallic materials can exhibit low-temperature serrated deformation (LTSD) at cryogenic temperatures, potentially causing sudden failures. Understanding LTSD is thus crucial for ensuring material reliability in such environments. LTSD has been explained by two main mechanisms: (i) dislocation-based mechanical instability and (ii) thermomechanical instability, but each has limitations when considered alone. To address this, we propose a new LTSD mechanism, a thermally induced dislocation dynamics model, based on cryogenic experimental evidence. This model accounts for dislocation avalanches and localized heating, leading to hierarchical dislocation networks and transitions in deformation modes. A modified deformation-mechanism map for SS316L is also presented. Our findings highlight the rate-dependent nature of LTSD and negative strain-rate sensitivity, including the first observation of links between small stress fluctuations and large serrations.
neutron imaging and diffraction analysis revealing spatial lithiation phase evolution in an ultra-thick graphite electrodeStrobl, M.*; Baur, M. E.*; Samothrakitis, S.*; Malamud, F.*; Zhang, X.*; Tung, P. K. M.*; Schmidt, S.*; Woracek, R.*; Lee, J.*; 鬼柳 亮嗣; et al.
Advanced Energy Materials, 15(20), p.2405238_1 - 2405238_9, 2025/05
被引用回数：9 パーセンタイル：91.57(Chemistry, Physical)Energy-efficient, safe, and reliable Li-ion batteries (LIBs) are required for a wide range of applications. The introduction of ultra-thick graphite anodes, desired for high energy densities, meets limitations in internal electrode transport properties, leading to detrimental consequences. Yet, there is a lack of experimental tools capable of providing a complete view of local processes. Here, a multi-modal measurement approach is introduced, enabling quantitative spatio-temporal observations of Li concentrations and intercalation phases in ultra-thick graphite electrodes. Neutron imaging and diffraction concurrently provide correlated multiscale information from the scale of the cell down to the crystallographic scale. In particular, the evolving formation of the solid electrolyte interphase (SEI), observation of gradients in total lithium content, as well as in the formation of ordered Li
C
phases and trapped lithium are mapped throughout the first charge-discharge cycle of the cell. Different lithiation stages co-exist during charging and discharging; delayed lithiation and delithiation processes are observed in central regions of the electrode, while the SEI formation, potential plating, and dead lithium are predominantly found closer to the interface with the separator. The study emphasizes the potential to investigate Li-ion diffusion and the kinetics of lithiation phase formation in thick electrodes.
Kim, M.*; Lee, C.*; 杉田 裕; Kim, J.-S.*; Jeon, M.-K.*
Geomechanics for Energy and the Environment, 41, p.100628_1 - 100628_9, 2025/03
被引用回数：2 パーセンタイル：57.80(Energy & Fuels)この研究では、DECOVALEX-2023プロジェクトの一環として幌延の地下研究施設で実施された実規模大の人工バリア試験の数値解析を使用して、非等温二相流のモデリングに対する主要変数の選択の影響を調査した。検証済みの数値モデルを使用して、人工バリアシステム内の不均質多孔質媒体の熱-水連成挙動を解析した。支配方程式を離散化する際の2つの異なる主要変数スキームを比較したところ、結果に大きな違いがあることが明らかになった。
Rajeev, H. S.*; Hu, X.*; Chen, W.-L.*; Zhang, D.*; Chen, T.*; 古府 麻衣子*; 梶本 亮一; 中村 充孝; Chen, A. Z.*; Johnson, G. C.*; et al.
Journal of the Physical Society of Japan, 94(3), p.034602_1 - 034602_14, 2025/03
被引用回数：2 パーセンタイル：41.22(Physics, Multidisciplinary)Two-dimensional hybrid organic-inorganic perovskites (HOIPs) have emerged as promising materials for light-emitting diode applications. In this study, by using time-of-flight neutron spectroscopy we identified and quantitatively separated the lattice vibrational and molecular rotational dynamics of two perovskites, butylammonium lead iodide (BA)
PbI and phenethyl-ammonium lead iodide (PEA)PbI. By examining the corresponding temperature dependence, we found that the lattice vibrations, as evidenced by neutron spectra, are consistent with the lattice dynamics obtained from Raman scattering. We revealed that the rotational dynamics of organic molecules in these materials tend to suppress their photoluminescence quantum yield (PLQY) while the vibrational dynamics did not show predominant correlations with the same. Additionally, we observed photoluminescence emission peak splitting for both systems, which becomes prominent above certain critical temperatures where the suppression of PLQY begins. This study suggests that the rotational motions of polarized molecules may lead to a reduction in exciton binding energy or the breaking of degeneracy in exciton binding energy levels, enhancing non-radiative recombination rates, and consequently reducing photoluminescence yield. These findings offer a deeper understanding of fundamental interactions in 2D HOIPs and could guide the design of more efficient light-emitting materials for advanced technological applications.
Lee, J.; Rossi, F.; 児玉 有; 弘中 浩太; 小泉 光生; 佐野 忠史*; 松尾 泰典*; 堀 順一*
Annals of Nuclear Energy, 211, p.111017_1 - 111017_7, 2025/02
被引用回数：1 パーセンタイル：20.46(Nuclear Science & Technology)Silica glass has been used as a base and host material in vitrified radioactive waste and lithium glass scintillator for neutron detection because of its superb transparency, high heat resistance, and excellent chemical inertness. Therefore, an accurate total cross section of the silica glass is important to evaluate the criticality safety for the vitrified wastes and to understand the neutron response for lithium glass scintillators accurately. In the present study, to provide the accurate total cross section in the thermal and epithermal energy range, the neutron transmission measurements were carried out by a pulsed neutron beam with the time-of-flight method at the Kyoto University Institute for Integrated Radiation and Nuclear Science - Linear Accelerator. We obtained the neutron total cross section of the silica glass in the energy region from 0.002 eV to 25 eV. The obtained results were compared and discussed with the previous results and the evaluated data.
小泉 光生; 伊藤 史哲*; Lee, J.; 弘中 浩太; 高橋 時音; 鈴木 敏*; 有川 安信*; 安部 勇輝*; Wei, T.*; 余語 覚文*; et al.
第45回日本核物質管理学会年次大会会議論文集(インターネット), 4 Pages, 2024/11
Neutron resonance transmission analysis (NRTA) is a non-destructive method applicable for measuring nuclear material using a time-of-flight (TOF) technique with a pulsed neutron source. To realize a high resolution compact NRTA system, use of a short-pulsed neutron source is essential. Laser-driven neutron sources (LDNSs) are well-suit for generating such neutron beams due to their short pulse width. The advances in laser technology will further reduce the system's size and improve practicality. In this study, we demonstrate the measurement of a neutron transmission TOF spectrum of a sample containing indium and silver using the LDNS of the Osaka University. The obtained spectrum was analyzed using the least-square nuclear-resonance fitting program, REFIT, showcasing for the first time the potential of an LDNS for nondestructive areal-density material characterization.
RhSi社本 真一; 山内 宏樹; 飯田 一樹*; 池内 和彦*; 金子 耕士; Chen, Y.-S.*; 矢野 真一郎*; Hsu, P.-T.*; Lee, M. K.*; Hall, A. E.*; et al.
Physical Review Research (Internet), 6(3), p.033303_1 - 033303_7, 2024/09
MnRhSiの磁気励起は少なくとも0.3から140meVに広がる。200Kでの非弾性散乱強度を積分することで、Mnサイト当たり約5
の磁気モーメントは、約5であることがわかった。一方で、長距離磁気秩序の磁気モーメントは4Kでわずか2.61であり、多くの部分が低温まで揺らいでいることがわかった。
小泉 光生; 伊藤 史哲*; Lee, J.; 弘中 浩太; 高橋 時音; 鈴木 敏*; 有川 安信*; 安部 勇輝*; Lan, Z.*; Wei, T.*; et al.
Scientific Reports (Internet), 14, p.21916_1 - 21916_9, 2024/09
被引用回数：5 パーセンタイル：64.02(Multidisciplinary Sciences)Laser-driven neutron sources (LDNSs) can generate strong short-pulse neutron beams, which are valuable for scientific studies and engineering applications. Neutron resonance transmission analysis (NRTA) is a nondestructive technique used for determining the areal density of each nuclide in a material sample using pulsed thermal and epithermal neutrons. Herein, we report the first successful NRTA performed using an LDNS driven by the Laser for Fast Ignition Experiment at the Institute of Laser Engineering, Osaka University. The key challenge was achieving a well-resolved resonance transmission spectrum for material analysis using an LDNS with a limited number of laser shots in the presence of strong background noise. We addressed this by employing a time-gated Li-glass scintillation neutron detector to measure the transmission spectra, reducing the impact of electromagnetic noise and neutron and gamma-ray flashes. Output waveforms were recorded for each laser shot and analyzed offline using a counting method. This approach yielded a spectrum with distinct resonances, which were attributed to 
In and 
Ag, as confirmed through neutron transmission simulation. The spectrum was analyzed using the least-square nuclear-resonance fitting program, REFIT, demonstrating the possibility of using an LDNS for nondestructive areal-density material characterization.
Nguyen, T.-D.*; Singh, C.*; Kim, Y. S.*; Han, J. H.*; Lee, D.-H.*; Lee, K.*; Harjo, S.; Lee, S. Y.*
Journal of Materials Research and Technology, 31, p.1547 - 1556, 2024/07
被引用回数：9 パーセンタイル：70.84(Materials Science, Multidisciplinary)This study investigates the mechanical properties of a friction-stir-welded (FSW) AA6061-T6 aluminum alloy at ultra-low temperature (ULT) of 20 K. In-situ neutron diffraction and orientation imaging microscopy were employed to compare the tensile deformation behavior of the base metal (BM) and heat-affected zone (HAZ) in the FSW aluminum plate. The results demonstrate that compared to room-temperature (RT), ULT induces a significant improvement in tensile strength and ductility in both the BM and HAZ. The enhanced mechanical properties in BM at ULT result from a more homogeneous deformation than occurs at RT. On the other hand, HAZ at ULT exhibits an even lower yield strength than at RT, but the strain hardening rate (SHR) is the most significant among the alloys, leading to a tensile strength of 346 MPa and the highest ductility of 46.8%. The lowest yield strength corresponds to the lowest-hardness zones in HAZ, caused by dissolved/coarsened precipitates during the FSW process.
Li-glass detector to gamma rays by a coincidence method伊藤 史哲*; Lee, J.; 弘中 浩太; 高橋 時音; 鈴木 敏*; 持丸 貴則*; 堀 順一*; 寺田 和司*; 小泉 光生
Nuclear Instruments and Methods in Physics Research A, 1064, p.169465_1 - 169465_9, 2024/07
被引用回数：0 パーセンタイル：0.00(Instruments & Instrumentation)The response of a gamma-ray spectrometer is generally determined by analyzing full-energy peaks. However, full-energy peaks cannot be measured easily in the case of scintillation detectors that consist of light elements, such as glass scintillators. Only a strong Compton plateau appears in the spectrum of such detectors. Therefore, Compton edgers were used to evaluate the response of these detectors. The response of a low-resolution Li-glass detector to gamma rays was measured for the first time by a coincidence method with a high-resolution LaBr:Ce detector using cascade gamma rays (2.75 and 1.37 MeV) from a 
Na source. Coincidence gates were applied at the peaks of the spectrum of the LaBr:Ce detector at the 0.51 MeV annihilation peak, and the sum peaks of a gamma ray and a backscattered gamma ray. By analyzing the gated spectra of the Li-glass detector, the energy-dependent detector response (i.e., the output strength and its dispersion) was determined.
Rossi, F.; Lee, J.; 児玉 有; 弘中 浩太; 小泉 光生; 堀 順一*; 寺田 和司*; 佐野 忠史*
Proceedings of 65th Annual Meeting of the Institute of Nuclear Materials Management (Internet), 8 Pages, 2024/07
Various non-destructive assay techniques are being used to verify different nuclear material. However, one of the difficulties of current NDA is the measurement of highly radioactive materials. Since 2015, the JAEA has been working on the development of various active non-destructive assay techniques to address some of the current challenges in nuclear safeguards. Among the various technologies proposed, the Neutron Resonance Analysis system combines signatures from NRTA, NRCA and the newly proposed NRFNA. The combination of those techniques can provide accurate information on the small fissile content in a sample. Neutrons are generated by a pulsed neutron source and slowed down into the moderator. Neutrons are collimated using lead and borated polyethylene to reach the sample, where various neutron-induced reactions occur. n/g PSD plastic scintillators are used to measure the captured gamma rays and fission neutrons at sample location. GS20 is used to collect the transmitted neutrons downstream of the source-sample beamline. A first measurement campaign was performed using natural uranium sample. The possibility of using NRFNA to identify fissile materials within a sample was clearly demonstrated, but the detectors used were not sufficient to achieve a good n/g PSD. New PSD scintillators were introduced. A first measurement campaign was performed in 2023. The acquired data are currently being analyzed, but preliminary results show distinct fission resonance peaks of increasing intensity with varying thicknesses of the same natural uranium samples. Currently, an assembly of multiple scintillators is being investigated to provide a better signal. The new setup will be tested starting in early 2024. In this paper, we will describe in detail the NRA project development and the latest results from experimental campaign. This work is supported by MEXT under the subsidy for the "promotion for strengthening nuclear security and the like"
Kim, Y. S.*; Chae, H.*; Lee, D.-Y.*; Han, J. H.*; Hong, S.-K.*; Na, Y. S.*; Harjo, S.; 川崎 卓郎; Woo, W.*; Lee, S.-Y.*
Materials Science & Engineering A, 899, p.146453_1 - 146453_7, 2024/05
被引用回数：12 パーセンタイル：80.27(Nanoscience & Nanotechnology)This work focused on the mechanical properties and serration-involved deformation behavior of advanced alloys at 15 K. Evolution of stacking faults and 
-martensite improved the mechanical performance of CoCrNi alloys, and significant strain-induced martensite transformation of DED-SS316L led to superior strength and strain hardening. A magnitude in stress drop was governed by dislocation density, phase type, and lattice defects, irrespective of processing method. FCC {200} notably was influenced recovery behavior after stress drop, and the contribution of strain energy density by serration on tensile toughness was the greatest for HR-CoCrNi.
Chae, H.*; Huang, E.-W.*; Jain, J.*; Lee, D.-H.*; Harjo, S.; 川崎 卓郎; Lee, S. Y.*
Metals and Materials International, 30(5), p.1321 - 1330, 2024/05
被引用回数：8 パーセンタイル：49.75(Materials Science, Multidisciplinary)In situ neutron diffraction during tensile deformation was performed for the stainless steels prepared by the additive manufacturing (AM) processes with two strategies: vertically built and horizontally built. The AM steels were further aged without solid solution treatment. As the results, the retained austenite was found to be more stable because the chemical composition became homogeneous by aging, and the onset of deformation induced martensitic transformation was delayed.
