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Kreinder, B.; Cox, I.*; Grzywacz, R.*; 西尾 勝久; 他24名*
Nuclear Instruments and Methods in Physics Research A, 1085, p.171298_1 - 171298_7, 2026/05
被引用回数：0In recent experiments, inorganic scintillators have been used to study the decays of exotic nuclei, providing an alternative to silicon detectors and enabling measurements that were previously impossible. However, proper use of these materials requires us to understand and quantify the scintillation process, specifically in response to very heavy nuclei. In this work, we show a simplified method based on the models of Birks (1951) and Meyer and Murray (1962) to parametrize the light output of inorganic scintillators in response to beams of energetic heavy ions over a broad range of energies. We test the accuracy of our parametrization approach by calculating light output and quenching factors for various ions and comparing them with experimental data from Lutetium Yttrium Orthosilicate (LYSO:Ce), a common inorganic scintillator. The Meyer-Murray model suggests that, for sufficiently heavy ions at high energies, the majority of the light output is associated with the creation of delta electrons, which are induced by the passage of the beam through the material. These delta electrons dramatically impact the response of detection systems when subject to ions with velocities typical of beams in modern fragmentation facilities. To illustrate this, we also present a qualitative estimate of the effects of delta rays on overall light output using the Birks-Meyer-Murray parametrization. The approach presented herein will serve as a basic framework for further, more rigorous studies of scintillator response to heavy ions. This work is a crucial first step in planning future experiments where energetic exotic nuclei are interacting with scintillator detectors.
Mohamad, A. B.; Chen, J.*; 井岡 郁夫*; 鈴木 恵理子; 近藤 啓悦; 阿部 陽介; 山下 真一郎; 大久保 成彰; 根本 義之; 岡田 裕史*; et al.
Journal of Nuclear Materials, 625, p.156513_1 - 156513_9, 2026/04
被引用回数：0Ion irradiation was carried out on Cr coating Zry cladding to investigate their microstructure evolution and mechanical properties. The sample was irradiated at reactor normal operation conditions. Microstructural observation and mechanical testing of non-irradiated samples and irradiated samples were performed to understand irradiation damage to the Cr-coated Zry cladding. Results of High Resolution Transmission Electron Microscopy and chemical analysis revealed Fe enrichment at the Cr coating and Zr substrate interface of irradiated samples due to irradiation enhanced diffusion or irradiation induced mixing. Irradiation led to the formation of Fe enrichment at the Cr Zr interface approximately 15nm. Moreover, hardening of the Cr coating and Zr substrate regions was observed in the irradiated sample.
Chen, J.*; 山本 慧; 他13名*
Physical Review Letters, 136(5), p.056702_1 - 056702_8, 2026/02
被引用回数：0The recently developed van der Waals magnets provide a promising platform for spintronics and magnonics. Here, we report the observation of surface magnon propagation in the van der Waals antiferromagnet CrSBr. We find a nearly unidirectional propagation of antiferromagnetic magnon modes, which emerge near the anticrossing of the optical and acoustic magnon bands, in agreement with our theory of magnetostatic waves in antiferromagnets. The propagation direction can be reversed by switching the magnetic field. The observed antiferromagnetic magnons operate in the gigahertz regime due to the weak interlayer exchange coupling. Our results open the pathway for nonreciprocal magnonic applications based on van der Waals antiferromagnets at easily-accessible microwave frequencies.
RhZhang, J. Z.*; Chen, Z. Q.*; Qu, T.*; Wang, Y. K.*; Li, Z. H.*; Orlandi, R.; 他62名*
Physics Letters B, 873, p.140144_1 - 140144_9, 2026/02
被引用回数：0At the RIKEN, 
-delayed 
-ray spectroscopy studies were conducted on 
Rh and 
Rh, resulting in the world's first successful identification of a 1/2
isomer in these isotope, extending the energy difference between the 9/2
and 1/2 states up to neutron number 
=74. Comparison of the new results with state-of-the-art calculations suggests that triaxial deformation plays a significant role in the evolution of the energy difference, indicating a shape transition from axially symmetric to triaxial deformation within the Rh isotopic series. These findings provide new insights into the structure of neutron-rich nuclei in the atomic number 
region, elucidating the interplay between triaxial deformation and shell evolution.
Dong, F.*; Xiao, Y.*; Chen, S.*; 出町 和之*; 高屋 茂; 吉川 雅紀
Advanced Engineering Informatics, 69(Part D), p.104094_1 - 104094_23, 2026/01
被引用回数：0 パーセンタイル：0.00(Computer Science, Artificial Intelligence)Ensuring safe and stable industrial plant operations requires accurate and timely fault diagnosis from multivariate time-series (MTS) sensor data. Conventional methods struggle with the complexity, high dimensionality, and limited feature extraction. To address this, we propose a novel end-to-end fault diagnosis framework that enhances class separability by leveraging instance-wise global and timestamp-wise local views of MTS representations. The dataset is augmented from the dual-view, and a complementary contrastive loss function captures both global and local contextual information. Unlike previous representation learning approaches, the diagnosis model's backbone and classifier are jointly optimized in an end-to-end scheme, ensuring aligned representations with the classification objective. Experimental results on simulated nuclear power plant fault datasets demonstrate the framework's effectiveness and robustness.
Wang, C.*; Yang, Z.*; Ren, Q.*; Mo. X.*; 吉川 貴史; 大門 俊介*; Diao, D.*; 齊藤 英治
Carbon, 246, p.120909_1 - 120909_7, 2026/01
被引用回数：0 パーセンタイル：0.00(Chemistry, Physical)Disordered carbon offers untapped potential for spin caloritronics. We report a phonon-enhanced spin-dependent Seebeck effect (SDSE) in a magnetic carbon film (MCF) with graphene nano-crystallites (10 nm), interfaced with Pt. In a longitudinal setup, the transverse thermoelectric voltage (
) peaks at (
) at 220 K, driven by a thermally induced spin current via the inverse spin Hall effect. Raman spectroscopy reveals a coincident G-band redshift peak, suggesting a phonon-spin resonance unique to MCF's hybrid structure. X-ray absorption spectra confirm stable sp
states, potentially mediating this effect. A multiple-sample study in addition reveals that smaller crystallites enhance SDSE. Unlike pristine graphene or insulators, MCF's weak ferromagnetism and phonon dynamics yield an unconventional spin-thermal regime. This finding redefines carbon's role in spin caloritronics, with tunable nano-crystallite size as a design parameter.
Guembou Shouop, C. J.; 土屋 晴文
Communications Engineering (Internet), 5, p.11_1 - 11_14, 2026/01
Neutron Resonance Transmission Analysis (NRTA) is a powerful non-destructive assay for material characterisation, traditionally requiring large, fixed and costly facilities. Here, we present a compact NRTA system utilising a small 
Cf spontaneous neutron source to analyse nuclear materials, offering a mobile and cost-effective alternative to accelerator, D-T, or laser-driven neutron sources. The pilot design, with a total size of 130 cm
50 cm50 cm, has an unprecedentedly short flight path of 42 cm, enabling time-of-flight measurements on nuclear material samples. The system's performance is demonstrated through NRTA measurements of simulated samples, including indium, hafnium, and cadmium metal plates. The resulting transmission spectra allow accurate isotope identification below 5 eV. These results underscore the system's potential for enhancing nuclear security, safeguards, and nonproliferation, particularly in scenarios where mobility, rapid deployment, and flexibility are critical. This work is supported by the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT) under the subsidy for the "promotion for strengthening nuclear security and the like."
Qin, T. Y.*; Hu, F. F.*; 徐 平光; Zhang, R.*; Su, Y. H.; Ao, N.*; Li, Z. W.*; 篠原 武尚; 菖蒲 敬久; Wu, S. C.*
International Journal of Fatigue, 202, p.109233_1 - 109233_16, 2026/01
被引用回数：2 パーセンタイル：0.00(Engineering, Mechanical)The surface induction-hardened S38C medium carbon steel shows a good balance of strength and toughness, but complicates the evaluation of fatigue resistance, mainly because of gradient residual stress (RS) and grains. An integrated fatigue resistance assessment (AIFA) framework was proposed to consider the residual stress relief under stochastic loads. To this end, quasi-in situ neutron diffraction and Bragg-edge imaging were combined to probe the evolution of residual stress during crack propagation. Firstly, a rigid-flexible coupled vehicle dynamics model was adopted to obtain the time-domain variable amplitude loading spectrum. Then, Fortran subroutines were developed to assign these data into full-scale S38C axle model, and the remaining life was predicted using the damage tolerance approach. The results demonstrate that crack propagation would accelerate when residual stress is considered in the case of the crack depth exceeding 3.0 mm. It is, for the first time, found that 15 mm- and 5 mm-thickness fan-shaped specimens can retain the axial and hoop residual strain in terms of diffraction angle variation, respectively, for full-scale structural S38C steel axles. In the absence of RS, the remaining life of the axle decreases sharply from 624,800 to 51,300 km as the crack depth increases from 3.0 to 16 mm. Compared with the standard method under constant amplitude loading without residual stress relief, the present AIFA method provides the more accurate but conservative fatigue life prediction.
-PuO
-PuO systemVinograd, V. L.*; Vauchy, R.
Journal of Nuclear Materials, 619, p.156244_1 - 156244_16, 2026/01
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)UO-PuO-PuO系における(U
Pu
)O
蛍石(FCC)と(UPu)Oビクスバイト(BCC)の熱力学的性質を、相平衡制約と酸素の化学ポテンシャルの関数としての酸素/金属比(O/M)の変化に関するデータを考慮して評価した。熱力学的には、BCCとFCCはともに秩序固溶体として記述され、
=-0.5と=-0.375(O/M=1.5とO/M=1.625)の特定の値において酸素/空孔分布の構成エントロピーを減少させることができる。このアプローチにより、PuO-PuO及びUO-PuO-PuOにおける蛍石/ビクスバイト平衡が少ない労力でよく再現された。さらに、UO-PuO-PuO系の実験データの大きな多様性が、個々の相のPu/(Pu+U)比が系全体のPu/(Pu+U)比と等しいままであること、すなわち、相間U/Pu分配が起こらないという仮定と矛盾しないことを示す。
上田 祐生; 小林 徹; 中村 聡志; 伴 康俊; 金田 結依; 生田目 望; Micheau, C.; 徳永 紘平; 中部 倫太郎; 金子 政志*; et al.
Langmuir, 42(1), p.1613 - 1626, 2026/01
被引用回数：0 パーセンタイル：0.00(Chemistry, Multidisciplinary)溶媒抽出系における金属イオンの選択性を支配する構造要因の理解は、高レベル放射性廃棄物の分離変換プロセスを高度化する上で極めて重要である。本研究では、代表的なランタニドとしてランタン(La)とネオジム(Nd)を対象に、ニトリロトリアセトアミド(NTAamide)抽出剤のアルキル側鎖分岐度が抽出挙動に及ぼす影響を系統的に調査した。分子量は同一だがアルキル分岐度の異なる4種類の抽出剤(いずれもアミド鎖の1本が炭素数8)を用い、硝酸濃度に対する分配比を測定した。さらに、LaおよびNdの局所配位構造を拡張X線吸収微細構造(EXAFS)で解析し、有機相における超分子的凝集挙動を小角中性子散乱(SANS)で評価した。その結果、EXAFS解析から、LaおよびNdの内圏配位環境はアルキル分岐度の影響をほとんど受けないことが明らかとなった。一方、SANS解析からは、分岐の少ない抽出剤ほど低硝酸濃度で大きな凝集体を形成し、特にNdにおいては凝集体形成が抽出を促進し、難溶性錯体の沈殿を防いでいることが示された。これらの結果は、アルキル分岐度が超分子的凝集挙動を強く制御し、それが抽出挙動を支配していることを示している。本研究は、ランタニドおよびアクチニドの溶媒抽出において、選択性向上のための新しい設計概念として「ナノスケール構造制御」の可能性を示すものである。
Villagrasa, C.*; Baiocco, G.*; Chaoui, Z.-E.-A.*; Dingfelder, M.*; Incerti, S.*; Kundr
t, P.*; Kyriakou, I.*; 松谷 悠佑; 甲斐 健師; Parisi, A.*; et al.
PLOS ONE (Internet), 21(1), p.e0340500_1 - e0340500_22, 2026/01
被引用回数：0電離放射線被ばくの生物学的影響を理解するために重要なナノ線量測定は、分子スケールでの原子相互作用を再現するMonte Carlo Track Structure (MCTS)コードにより評価可能である。数十年にわたり独立して開発された様々なMCTSコードは、生物組織の主成分である液体水中の電子線の相互作用について、異なる物理モデルと断面積データセットを使用してきた。本研究では、様々なMCTSコード内の相互作用断面積の違いによって生じるナノ線量測定計算の不確実性を評価した。7つのMCTSコード(Geant4-DNA, PARTRAC, PHITS, MCwater、およびPTra)の計算結果から、平均電離数や2回以上の電離が起こる確率などの分子スケールの物理量に大きな相違があることが明らかとなった。最も大きな相違が確認されたのは低エネルギー電子で、相互作用断面積の寄与が不確実性の主要因であることがわかった。本成果より、断面積の相違が複雑なDNA損傷などの生物学的影響に無視できない影響を与えることが浮き彫りになった。
Fe
O
Lenander, E. Y.*; Nielsen, F. B.*; Lass, J.*; Hansen, U. B.*; Krighaar, K. M. L.*; Preuss, A.*; Weber, T.*; Enderle, M.*; Jacobsen, H.*; Stuhr, U.*; et al.
Physical Review B, 113(1), p.014424_1 - 014424_14, 2026/01
被引用回数：0The frustrated magnet BiFeO has been reported to exhibit complex spin dynamics coexisting with conventional spin wave excitations. The magnetic Fe
(
) ions are arranged into a distorted two-dimensional Cairo pentagonal lattice with weak couplings between the layers, developing long-ranged noncollinear antiferromagnetic order below 245 K. In order to enable studies and modeling of the complex dynamics close to 
, we have reexamined the magnetic excitations across the complete energy scale (
meV) at 10 K. We discover two distinct gaps, which can be explained by introducing, respectively, easy axis and easy plane anisotropy on the two unequivalent Fe sites. We develop a refined spin Hamiltonian that accurately accounts for the dispersion of essentially all spin-wave branches across the full spectral range, except around 40 meV, where a splitting and dispersion are observed. Polarization analysis shows that the system has magnetic anisotropic fluctuations, consistent with our model. A continuum of scattering is observed above the spin wave branches and is found to principally be explained by an instrumental resolution effect. The full experimental mapping of the excitation spectrum and the refined spin Hamiltonian provides a foundation for future quantitative studies of spin waves coexisting with unconventional magnetic fluctuations in this frustrated magnet found at higher temperatures.
-wave 
baryonsSu, N.*; Chen, H.-X.*; Gubler, P.; 保坂 淳
Physical Review D, 113(1), p.016005_1 - 016005_7, 2026/01
被引用回数：1Using the QCD sum rule method, we investigate the mass splitting for the spin-orbit partner states of the 
baryon assuming that it is a -wave excitation with 
. This study is an extension of a previous work, in which the masses of these states were estimated with uncertainties too large to extract the reliable mass splitting. In the present study, by directly formulating a sum rule for the mass splitting, we obtain an improved prediction, 
MeV. This result provides a more quantitative insight into the spectrum of -wave baryons and serves as a useful reference for future experiments.
quartz irradiated with swift heavy ions; Thickness and edge effects石川 法人; 田口 富嗣*; 小河 浩晃; Toimil-Molares, M. E.*; Trautmann, C.*
Physical Review Materials (Internet), 10(1), p.016001_1 - 016001_7, 2026/01
被引用回数：0結晶性SiO(石英)試料に1.64GeVおよび200MeVのAuイオンを照射し、イオントラック形成に由来する照射誘起ナノ構造を透過型電子顕微鏡(TEM)を用いて調査した。解析の結果、通常観察される均一な非晶質イオントラックだけでなく、同心円状のコア-ハロー構造(イオン飛跡に沿った低密度コアとハロー損傷領域)を持つトラックも観察された。後者のタイプのトラックは、厚さが50nm未満の薄い試料領域でのみ確認され、こうした低密度コアを持つトラックの形成には薄い試料が必要条件であることが示唆された。さらに、試料端部ではクレーター状の構造を持つピット状トラックも確認された。表面を含む試料の形態が、複雑なナノ構造の形状に影響を与えていることが強く示唆された。これらの結果について、電子スパッタリングなどの表面現象や、試料の厚さおよび試料端効果の観点から議論した。
from QCD sum rulesSu, N.*; Chen, H.-X.*; Gubler, P.; 保坂 淳
Proceedings of Science (Internet), 500, p.076_1 - 076_6, 2026/01
We investigate the recently observed baryon using QCD sum rules. By constructing P-wave baryon currents and performing spin projection and parity projection, we obtain the masses of the 
and 
states as 
GeV and 
GeV, in good agreement with experiment. This suggests that is likely to be a negative parity P-wave excited state, though its spin remains undetermined and requires further study of its decay properties.
Chong, Y.*; 都留 智仁; Gholizadeh, R.*; Minor, A. M.*; 辻 伸泰*
Acta Materialia, 301, p.121523_1 - 121523_12, 2025/12
被引用回数：3 パーセンタイル：71.48(Materials Science, Multidisciplinary)六方最密充填(HCP)チタン合金は、非対称なHCP結晶構造のため本質的に独立した滑り系が少ないため、大きな延性を達成するには双晶形成が不可欠である。一般に双晶形成は原理的には微量の格子間酸素によって抑制され、チタンの延性が大幅に低下することが知られているが、その根本的なメカニズムは議論の余地がある。本研究では、Ti-O合金の双晶形成/双晶回復挙動に関する体系的なマルチスケール研究を報告し、格子間酸素が双晶形成を阻害する要因を検討した。アトムプローブトモグラフィーを使用して、酸素原子が{10
2}
引張双晶境界と{11
2}圧縮双晶境界の両方に偏析することを初めて明らかにした。また、第一原理計算によって、酸素シャッフルメカニズムによる双晶境界への酸素原子の強いピン止め効果が示され、これにより異なる温度でのTi-O合金の双晶境界の特異な移動形態を説明することに成功した。これらの実験と計算による研究から得られた知見は、格子間不純物含有量の変動に対する許容度を高めたチタン合金の設計の根拠となり、この高強度で軽量な材料のより広範な使用に大きな意味をもたらす。
Dechenaux, B.*; Brovchenko, M.*; 荒木 祥平; 郡司 智; 須山 賢也
Annals of Nuclear Energy, 223, p.111555_1 - 111555_11, 2025/12
被引用回数：0 パーセンタイル：0.00(Nuclear Science & Technology)The safe retrieval of the fuel debris generated during the Fukushima Daiichi nuclear accident poses a number of challenges, among which an important one is to ensure the criticality safety of the recovery operations. At the heart of the problem lies the intrinsically heterogeneous nature of the problem, and the appearance of complex and disordered media whose neutronic properties are difficult to accurately characterize and reproduce in neutron transport simulations. Typically, a similar, simpler, problem is encountered in the modeling of assemblies with missing fuel rods. In both problems, the availability of experimental facilities capable of validating both the nuclear data and the simulation schemes in heterogeneous configurations is crucial. The modified STACY installation has been specially designed to provide and carry out critical experiments, allowing for highly non-uniform configurations, that will directly support fuel debris recovery operations, but can also be used for other experimental programs. The present work describes a method to consistently and orderly sample non-uniform core configurations in the modified STACY facility, and proposes two critical heterogeneous core configurations. They have the advantage to present a high sensitivity to the water thermal scattering law, whose importance was found to be more significant for more heterogeneous configurations. The proposed experiments will contribute to the exploration and validation of heterogeneous critical systems.
Cf中性子源を用いた卓上型中性子共鳴透過分析装置の開発土屋 晴文; Guembou Shouop, C. J.
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
Neutron Resonance Transmission Analysis (NRTA) is a non-destructive assay capable of identifying and quantifying nuclear materials with high precision, making it a promising tool for applications in nuclear security, safeguards, and non-proliferation. Conventional NRTA systems typically employ accelerators or neutron generators as neutron sources. As a result, they are large, require heavy shielding, and are difficult to implement in facilities with limited space or in field environments. To overcome these limitations, we developed a table-top NRTA system that utilizes a Cf neutron source instead of an accelerator or a neutron generator. The apparatus has dimensions of approximately 130 cm 50 cm 50 cm, enabling easy transport and on-site deployment. Performance tests were conducted using indium and silver plates as surrogate samples for nuclear materials. The experimental transmission spectra exhibited resonance dips consistent with those of expected transmission spectra incorporating the system response function. From these comparisons, the isotopic areal densities were successfully quantified within experimental uncertainty. This study demonstrates, for the first time, that isotope identification and quantitative evaluation can be achieved using a table-top NRTA system without accelerators and neutron generators, and suggests its potential applicability to nuclear facilities, ports, and other space-limited locations.
白藤 雅也; 佐野 恭平; 堀内 雅一; 加藤 茜; 渡邉 一樹; 谷川 聖史; 丸山 創; 北尾 貴彦; Conner, J.*; LaFleur, A.*; et al.
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, in collaboration with the U.S. Department of Energy and Los Alamos National Laboratory, initiated a joint research project to develop the Advanced Hulls Measurement and Monitoring System (A-HMMS) for quantifying trace amounts of nuclear material in hull drums. Monte Carlo simulations using the MCNP code confirmed that the presence of water significantly attenuates neutron count rates. However, sufficient sensitivity to plutonium mass variations was observed, indicating that measurements are feasible even with water present. Passive NDA methods based on the Cm/Pu ratio were found to be limited due to curium decay over long-term storage, necessitating the use of active interrogation techniques. Small-scale experiments validated the simulation results and demonstrated that waste type and source position significantly affect count rates, highlighting the need for waste-specific calibration curves. Full-scale testing is planned to evaluate system performance under realistic conditions and optimize the A-HMMS design.
Malatesta, L. C.*; 末岡 茂; Wei
, N.-M.*; Gailleton, B.*; 塚本 すみ子*; 石村 大輔*; 高橋 直也*; 西村 卓也*; 片岡 香子*; 小松 哲也; et al.
Geophysical Research Letters, 52(24), p.e2025GL116602_1 - e2025GL116602_10, 2025/12
被引用回数：0 パーセンタイル：0.00(Geosciences, Multidisciplinary)The eastern margin of the Sea of Japan is a zone of great seismic and tsunami hazard due to multiple offshore and nearshore reverse faults as shown by the 2024 Mw7.5 Noto Peninsula Earthquake. Here we compare coseismic deformation of the 2024 Noto Peninsula Earthquake with 4,767 individual marine terraces attributed to 16 successive sea-level stages over the last Myr. This reveals that the earthquake faults started slipping between 326 and 238 ka. The emerged landscape is still adjusting to it while nearshore underwater scarps mark the active faults. Applied to nearby Sado Island, these observations reveal the likely location of an active fault that drives its fast deformation. Active faults defining the edge of uplifting land are likely found in the near shore domain, drowned by the current sea-level high stand.
