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Yee-Rendon, B.; 近藤 恭弘; 田村 潤; 明午 伸一郎; 前川 藤夫; Pla
ais, A.*; Bouly, F.*
Proceedings of 22nd International Conference on RF Superconductivity (SRF2025) (Internet), p.316 - 320, 2026/04
加速器駆動システム(ADS)などの大強度加速器には、高い可用性と信頼性が求められる。高い可用性の達成には、高周波空洞の1つが故障した場合でも、空洞補償により運転を継続できる能力が重要な鍵となる。JAEA-ADS線形加速器のビームダイナミクス研究では、複数の高周波空洞が故障した場合でも、許容なビーム品質を維持した状態で運転が継続できることが示されている。海外の他の超伝導線形加速器でも同様の方法を採用し、独自の手順を開発している。LightWinツールは、線形加速器における空洞故障ごとの補償設定を自動的かつ体系的に特定する効果的なツールとなり、SPIRAL2の運転を容易にするためにテストと改良が進められている。本ソフトウェアは、MINERVAの線形加速器だけでなく、JAEA-ADS線形加速器の高エネルギー加速部でも効果的となることが示された。本研究では、LightWinを用いてJAEA-ADS超伝導線形加速器における空洞補償を解析し、過去の研究結果との比較により、その有効性を議論する。
Guerinoni, E.*; 上田 祐生; 元川 竜平; Zemb, T.*; Pellet-Rostaing, S.*; Dourdain, S.*
Langmuir, 42(12), p.8313 - 8321, 2026/03
Third phase formation in liquid-liquid extraction poses operational challenges by inducing organic phase separation, limiting extraction efficiency and process safety. Here, we employ combined ultra-small-angle X-ray (USAXS) and neutron scattering (USANS) to elucidate pre-transitional structures occurring during uranium extraction by tri-octylamine (TOA) in octane as diluent. SAXS highlights uranium-filled aggregates, while SANS captures all aggregates, regardless of uranium content. Extending the q-range from 0.004 to 3 
reveals two distinct populations: small spherical reverse micelle-like aggregates (radius 11 AA) and larger fluctuating domains exceeding 150 nm, consistent with Ornstein-Zernike critical fluctuations. Increasing TOA concentration amplifies these superstructures until divergence, the formation of a third phase. This study demonstrates that phase instability originates from the hierarchical condensation of water-filled aggregates around uranium-filled aggregates, rather than from simple micelle growth. Predicting such instability therefore requires accounting for the complete distribution of species, including water. The U-U distance in neighboring aggregate forming a supercluster is evidenced without ambiguity. Understanding such multiscale pre-transitional phenomena offers new routes to predict and mitigate phase separation in solvent extraction processes critical for nuclear fuel recycling.
Valet, T.*; 山本 慧; Pigeau, B.*; de Loubens, G.*; Klein, O.*
Physical Review B, 113, p.L100410_1 - L100410_6, 2026/03
In the context of a growing interdisciplinary interest in the angular momentum of wave fields, the spin-wave case has yet to be fully explored, with the extensively studied notion of spin transport being only part of the broader picture. Here we report experimental evidence for non-zeromagnon orbital angular momentum inside magnetic disk, by resolving the frequency splitting between magnon modes with counter-rotating wavefronts and thereby avoiding formation of azimuthal standing waves. This requires an unambiguous formulation of spin and orbital angular momenta for spin waves, which we provide in full generality taking advantage of a systematic application of quantum field theory techniques as detailed in an associated article. The results unequivocally establish magnetic dipole-dipole interactions as a magnetic-field controllable spin-orbit interaction for magnons. Our findings open a new research direction, leveraging the spectroscopic readability of angular momentum for azimuthal spin waves and other related systems.
Valet, T.*; 山本 慧; Pigeau, B.*; de Loubens, G.*; Klein, O.*
Physical Review B, 113(10), p.104437_1 - 104437_17, 2026/03
被引用回数：0In the context of an ever-expanding experimental and theoretical interest in the magnetization dynamics of mesoscopic magnetic structures, both in the classical and quantum regimes, we formulate a low-energy field theory for the linear spin waves in finite and textured ferromagnets and we perform its constrained canonical quantization. The introduction of a manifestly gauge invariant Lagrangian enables a straightforward application of the Noether's theorem. Taking advantage of this in the context of a broad class of axisymmetric ferromagnets of special conceptual and experimental relevance, a general expression of the conserved and quantized spin-wave total angular momentum is rigorously derived, while separate conservation and quantization of its orbital and spin components are established for a more restricted class of uniaxial exchange ferromagnets. Further particularizing this general framework to the case of axially saturated magnetic thin disks, we develop a semi-analytic theory of the low frequency part of the exchange-dipole azimuthal spin-wave spectrum, providing a powerful theoretical platform for the analysis and interpretation of magnetic resonance experiments on magnetic microdots as further demonstrated in a joint paper.
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."
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：2 パーセンタイル：92.64(Multidisciplinary Sciences)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。
Kyriakou, I.*; Papadopoulos, A.*; Polopetrakis, I.*; Kotroumbelou, C.*; Plante, I.*; 松谷 悠佑; 甲斐 健師; Qiu, R.*; Li, J.*; Kundrt, P.*; et al.
Physics in Medicine & Biology, 39 Pages, 2026/00
過去40年間にわたり、液体の水を対象としたモンテカルロ飛跡構造(MCTS)コードが世界中で数多く開発されてきたが、相互作用断面積は大きく異なる。本研究では、6種類の異なるMCTSコードの使用による、液相水中の低エネルギー電子輸送の物理的特性(電子阻止能、経路長、dose-point-kernel、微視的線量付与)の不確実性を評価することを目指した。コード間比較の結果により、特に100eV以下の低エネルギー領域において、MCTSコード間で大きな差異があることが明らかになり、電子線が重要な役割を果たすDNA損傷シミュレーションの精度に影響を与えることが示された。本研究は、液相水中の低エネルギー電子輸送計算に伴う不確実性を低減するために、MCTSコードで使用される物理モデルの更なる開発の必要性を浮き彫りにしている。
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.
Ji, Y.-Y.*; Joung, S.*; Ji, W.*; 越智 康太郎; 佐々木 美雪; 眞田 幸尚
Journal of Radiological Protection, 45(4), p.042501_1 - 042501_11, 2025/12
被引用回数：1 パーセンタイル：96.41(Environmental Sciences)本研究では、LaBr
(Ce)検出器を用いた韓国原子力研究院の無人航空機搭載型ガンマ線スペクトロメトリーシステムの開発と実地検証について報告する。FDNPP付近における日本原子力研究開発機構との共同調査では、高度に基づく減衰補正を適用後、信頼性の高い線量率推定が得られたが、傾斜地では差異が生じた。緊急対応用途における精度向上のため、地形データの組み込みが推奨される。
Catumba, G.*; 平口 敦基; Hou, G. W.-S.*; Jansen, K.*; Kao, Y.-J.*; David Lin, C.-J.*; Ramos, A.*; Sarkar, M.*
Proceedings of Science (Internet), 466, p.145_1 - 145_10, 2025/12
SU(2)ゲージ場を持つカストディアル2ヒッグス二重項模型を格子上で研究する。この模型は標準模型と同じ大域的対称性を持つが、ヒッグス場が追加されることでスカラースペクトルが拡大し、大域的対称性の自発的破れが発生する可能性が出てくる。カストディアル2ヒッグス二重項模型のスペクトルと走るゲージ結合定数を、カットオフが300から600GeVで標準模型での物理量が一定となる線上で研究した。結果として追加したBSMスカラー場の実現可能な質量の下限は、Wボソンの質量よりはるかに小さいことがわかった。そして、この研究で選択した4点相互作用の結合定数では、BSM状態の1つに対する推定された下限質量は約
0.2
で、カットオフに依存しないことがわかった。
Jing, Z.*; 山口 敏男*; 町田 真一*; 服部 高典; Zhou, Y.*
Journal of Chemical Physics, 163(19), p.194505_1 - 194505_12, 2025/11
被引用回数：0 パーセンタイル：0.00(Chemistry, Physical)ギガパスカル(GPa)範囲の圧力におけるイオンの溶媒和は、高圧化学合成および地球内部における物質循環にとって極めて重要である。我々は、0.1MPaおよび0.7GPa/298KにおけるMCl (M = Li, Na, K, Rb, Cs)の重水素化水溶液について、中性子散乱(NS)実験および分子動力学(MD)シミュレーションを実施した。経験的ポテンシャル構造精密化(EPSR)手法を用いてNSデータを分析した。0.7GPaへの圧縮に伴い、外殻水分子がイオンの最近接原子殻に入り込み、溶媒和イオンクラスターは高密度化する。第一溶媒和殻における水分子双極子の配向分布に基づく水和因子
と静的水和数
は、圧縮がイオンの水和能力を弱めることを示す。圧縮はイオン拡散、特に構造破壊イオンの拡散を抑制する。イオン拡散係数
、水分子滞留時間
、動的水和数
は、高圧下でRb
とCsが構造形成イオンの特性を示すことを示す。動的特性は静的構造よりも圧力に敏感である。
, I
and HDO onto pre-Neogene sedimentary rocksHou, L.*; 深津 勇太; 岡本 駿一*; 戸田 賀奈子*; 中田 弘太郎*; 野原 慎太郎*; 石寺 孝充; 斉藤 拓巳*
Journal of Nuclear Science and Technology, 62(11), p.1121 - 1134, 2025/11
被引用回数：1 パーセンタイル：59.09(Nuclear Science & Technology)This study investigates the diffusion behaviors of Cs, I, and HDO in a pre-Neogene sedimentary rock as a potential host rock for high-level radioactive waste (HLW) disposal in Japan. Through-diffusion experiments were conducted to reveal distinct patterns in their breakthrough curves. Cs exhibited the fastest diffusion among the tracers, significantly influenced by fractures, surface diffusion mechanisms, and aragonite formation. In contrast, the anion exclusion effect notably hindered the diffusion behavior of I. The results highlight the diverse diffusion and retardation properties of pre-Neogene sedimentary rocks, showing that the effective diffusion coefficient of HDO is more similar to that of crystalline rocks. These findings contribute to the understanding of the suitability of pre-Neogene sedimentary rocks as a potential natural barrier for HLW repositories.
Spitz, L.*; Razpopov, A.*; Biswas, S.*; Lane, H.*; Nikitin, S. E.*; 飯田 一樹*; 梶本 亮一; 藤田 全基*; 新井 正敏*; Mourigal, M.*; et al.
Physical Review B, 112(18), p.184302_1 - 184302_18, 2025/11
被引用回数：1 パーセンタイル：41.30(Materials Science, Multidisciplinary)CuGeO has long been studied as a prototypical example of the spin-Peierls transition in a 
Heisenberg chain. Despite intensive investigation of this quasi-one-dimensional material, systematic measurements and calculations of the phonon excitations in the dimerized phase have not to date been possible, leaving certain aspects of the spin-Peierls phenomenon unresolved. We perform state-of-the-art density functional theory (DFT) calculations to compute the electronic structure and phonon dynamics in the low-temperature dimerized phase. We also perform high-resolution neutron spectroscopy to measure the full phonon spectrum over multiple Brillouin zones. We find excellent agreement between our numerical and experimental results that extend to all measurement temperatures. Notable features of our phonon spectra include a number of steeply dispersive modes, nonmonotonic dispersion features, and specific phonon anticrossings, which we relate to the mode eigenvectors. By calculating the magnetic interactions within DFT and studying the effects of different phonon modes on the superexchange paths, we discuss the possibility of observing spinphonon hybridization effects in experiments performed both in and out of equilibrium.
Jeong, S. G.*; Kwon, J.*; Kim, E. S.*; Prasad, K.*; Harjo, S.; Gong, W.; 川崎 卓郎; Estrin, Y.*; Bouaziz, O.*; Hong, S. I.*; et al.
Materials Science & Engineering A, 942, p.148712_1 - 148712_11, 2025/10
被引用回数：1 パーセンタイル：40.12(Nanoscience & Nanotechnology)The cellular structure plays a key role in determining the mechanical properties of metal additive manufacturing (MAM) components. This study presents in situ neutron diffraction and dislocation density-based modeling for a CoCrFeMnNi high-entropy alloy (HEA) made via directed energy deposition (DED). A constitutive model based on the Kocks-Mecking-Estrin framework was used to represent the cellular structure. Parametric analysis showed lower dislocation accumulation and annihilation rates in the as-built sample (with cellular structure) than in the heat-treated one. These differences are linked to dislocation forest networks and local stacking fault energy variations. Dislocation density across cell interiors and walls was also compared with deformation-induced dislocation cells.
Guerinoni, E.*; Zemb, T.*; 元川 竜平; 上田 祐生; 青柳 登; Pellet-Rostaing, S.*; Dourdain, S.*
Journal of Physical Chemistry B, 129(32), p.8210 - 8217, 2025/08
被引用回数：1 パーセンタイル：47.51(Biophysics)Liquid-liquid extraction of uranium involves an acidic aqueous phase in contact with an oil phase containing aliphatic amines and a linear alkane. Excess electrolyte in the oil phase leads to a third phase, hindering metal ion extraction and stripping. We determine the largest admissible extractant concentration (LOC) before macroscopic phase separation. Using small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS), we analyze the microstructure of the phases. In all aliphatic diluents, the third phase consists of weak water-in-oil (w/o) aggregates with interdigitated hydrocarbon chains. Even after centrifugation, SANS detects residual deuterated solvent molecules. A fraction of these w/o aggregates contains uranium(VI) cations (U-loaded aggregates), which exhibit stronger attractive interactions than unloaded aggregates. This leads to the segregation of U-loaded aggregates into large clusters, detected as a Porod-type decay in SAXSbut absent in SANS at a low q-values.
青山 高士; Choudhary, S.*; Pandaleon, A.*; Burns, J. T.*; Kokaly, M.*; Restis, J.*; Ross, J.*; Kelly, R. G.*
Corrosion, 81(6), p.609 - 621, 2025/06
被引用回数：1 パーセンタイル：40.12(Materials Science, Multidisciplinary)This study presents a new test method for inducing controlled corrosion damage within simulated fastener holes of aluminum alloys, aimed at pretreating fatigue test specimens. The method involves insulating the outer surface while exposing the fastener hole surface to electrolytes containing 0.66 M NaCl + 0.1 M AlCl with varying concentrations of K 
S O 
. The evolution of corrosion damage within the fastener hole was examined as a function of exposure duration, electrolyte composition, and volume, as well as the effect of galvanic coupling with a SS316 cathode. Results indicate that fissure depth increases with an increase in K S O concentration but does not progress further after 24-48 hours of exposure in the chemical, or freely-corroding, exposure test. In contrast, galvanic coupling with a SS316 plate significantly accelerates corrosion, leading to much deeper fissures in a shorter time. The importance of electrolyte replenishment has been explored using electrochemical measurements, revealing the impact of evolving electrolyte chemistry. Beyond its application in fatigue specimen pretreatment, this method provides a simple yet effective approach for studying localized corrosion and evaluating mitigation strategies for fastener holes in aerospace structures.
Fablet, L.*; P
drot, M.*; Choueikani, F.*; Kieffer, I.*; Proux, O.*; Pierson-Wickmann, A.-C.*; Cagniart, V.*; 蓬田 匠; Marsac, R.*
Environmental Science; Nano, 12(5), p.2815 - 2827, 2025/05
被引用回数：3 パーセンタイル：75.05(Chemistry, Multidisciplinary)ニッケル(Ni)は環境中に遍在する微量元素である。Niは酸化鉄ナノ粒子との親和性が高く、土壌や水中から酸化鉄ナノ粒子、特に環境中に普遍的に存在する磁鉄鉱によって除去することができれば、環境浄化のための新たな戦略の1つとなり、その研究の意義は大きい。しかし、磁鉄鉱の化学量論(Fe(II)とFe(III)の比率)を制御することが困難であるため、Niと磁鉄鉱の相互作用は十分に理解されていなかった。そこで本研究では、異なるFe(II)とFe(III)の比率を持つ磁鉄鉱ナノ粒子を用い、吸着実験とX線吸収分光法によって溶液中と嫌気雰囲気下におけるNiと磁鉄鉱の相互作用を調べた。この研究により明らかにされた磁鉄鉱とNiの相互作用は、将来的にNi汚染の環境浄化戦略を立案する上で重要な知見となりうる。
under pressureKnafo, W.*; Thebault, T.*; Raymond, S.*; Manuel, P.*; Khalyavin, D. D.*; Orlandi, F.*; Ressouche, E.*; Beauvois, K.*; Lapertot, G.*; 金子 耕士; et al.
Physical Review X, 15(2), p.021075_1 - 021075_16, 2025/05
被引用回数：7 パーセンタイル：93.77(Physics, Multidisciplinary)The discovery of multiple superconducting phases in UTe boosted research on correlated-electron physics. This heavy-fermion paramagnet was rapidly identified as a reference compound to study the interplay between magnetism and unconventional superconductivity with multiple degrees of freedom. The proximity to a ferromagnetic quantum phase transition was initially proposed as a driving force to triplet-pairing superconductivity. However, we find here that long-range incommensurate antiferromagnetic order is established under pressure. The propagation vector k
= (0.07, 0.33, 1) of the antiferromagnetic phase is close to a wavevector where antiferromagnetic fluctuations have previously been observed at ambient pressure. These elements support that UTe is a nearly-antiferromagnet at ambient pressure. Our work appeals for theories modelling the evolution of the magnetic interactions and electronic properties, driving a correlated paramagnetic regime at ambient pressure to a long-range antiferromagnetic order under pressure. A deeper understanding of itinerant-f-electrons magnetism in UTe will be a key for describing its unconventional superconducting phases.
Joung, S.*; Ji, Y.-Y.*; Choi, Y.*; Lee, E.*; Ji, W.*; 佐々木 美雪; 越智 康太郎; 眞田 幸尚
Journal of Instrumentation (Internet), 20(4), p.P04027_1 - P04027_10, 2025/04
被引用回数：1 パーセンタイル：47.48(Instruments & Instrumentation)An airborne survey system named the MARK-A1 was previously developed to be mounted on an unmanned aerial vehicle for the purpose of application in contaminated areas with high dose rate levels. The MARK-A1 system consists of a CZT detector, signal processing unit, and positioning and interface units linked to a PC on the ground. The weight of the system is below 1 kg for loading on a commercial drone. In the current work, for experimental verification, field testing was conducted in a high dose rate environment near the Fukushima Daiichi Nuclear Power Plant. With the cooperation of the Japan Atomic Energy Agency, the MARK-A1 was installed on an unmanned aerial vehicle to conduct airborne surveys using two flight methods, namely a flat flight and a step flight, at various speeds. The airborne survey data were converted to gamma dose rates at a height of 1 m above the ground using a flat source model to create contamination maps. For a comparative evaluation of the airborne survey results, an in situ survey was also conducted in the survey area, and it was confirmed that the step flight method better matched the surface survey results.
Cho, S. H.*; Cho, S. W.*; Lv, Z.*; 関根 由莉奈; Liu, S.*; Zhou, M.*; Nuxoll, R. F.*; Kanatzidis, E. E.*; Ghaffari, R.*; Kim, D.*; et al.
Lab on a Chip, 25(7), p.1647 - 1655, 2025/04
被引用回数：10 パーセンタイル：98.18(Biochemical Research Methods)アミノ酸は体内のタンパク質合成と代謝プロセスに不可欠な物質である。本研究では、運動中の汗からのアミノ酸損失について定量的に調べることを目的とした。汗中のアミノ酸含有量をリアルタイムで分析するため、測定のための技術基盤としてウェアラブルなマイクロ流体システムを構築した。定量分析を実現するため、ウェアラブルデバイスに蛍光アッセイを組み込み、さらにスマートフォンベースの画像化技術を統合させたシステムを開発した。
