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Xia, C.-J.*; 丸山 敏毅; 安武 伸俊*; 巽 敏隆*; Zhang, Y.-X.*
Physics Letters B, 839, p.137769_1 - 137769_5, 2023/04
Realistic estimations on the elastic properties of neutron star matter are carried out with a large strain (
0.5) in the framework of relativistic-mean-field model with Thomas-Fermi approximation, where various crystalline configurations are considered in a fully three-dimensional geometry with reflection symmetry. Our calculation confirms the validity of assuming Coulomb crystals for the droplet phase above neutron drip density, which nonetheless does not work at large densities since the elastic constants are found to be decreasing after reaching their peaks. Similarly, the analytic formulae derived in the incompressible liquid-drop model give excellent description for the rod phase at small densities, which overestimates the elastic constants at larger densities. For slabs, due to the negligence on the variations of their thicknesses, the analytic formulae from liquid-drop model agree qualitatively but not quantitatively with our numerical estimations. By fitting to the numerical results, these analytic formulae are improved by introducing dampening factors. The impacts of nuclear symmetry energy are examined adopting two parameter sets, corresponding to the slope of symmetry energy L = 41.34 and 89.39 MeV. Even with the uncertainties caused by the anisotropy in polycrystallines, the elastic properties of neutron star matter obtained with L = 41.34 and 89.39 MeV are distinctively different, results in detectable differences in various neutron star activities.
岩本 修; 岩本 信之; 国枝 賢; 湊 太志; 中山 梓介; 安部 豊*; 椿原 康介*; 奥村 森*; 石塚 知香子*; 吉田 正*; et al.
Journal of Nuclear Science and Technology, 60(1), p.1 - 60, 2023/01
The fifth version of Japanese Evaluated Nuclear Data Library, JENDL-5, was developed. JENDL-5 aimed to meet a variety of needs not only from nuclear reactors but also from other applications such as accelerators. Most of the JENDL special purpose files published so far were integrated into JENDL-5 with revisions. JENDL-5 consists of 11 sublibraries: (1) Neutron, (2) Thermal scattering law, (3) Fission product yield, (4) Decay data, (5) Proton, (6) Deuteron, (7) Alpha-particle, (8) Photonuclear, (9) Photo-atomic, (10) Electro-atomic, and (11) Atomic relaxation. The neutron reaction data for a large number of nuclei in JENDL-4.0 were updated ranging from light to heavy ones, including major and minor actinides which affect nuclear reactor calculations. In addition, the number of nuclei of neutron reaction data stored in JENDL-5 was largely increased; the neutron data covered not only all of naturally existing nuclei but also their neighbor ones with half-lives longer than 1 day. JENDL-5 included the originally evaluated data of thermal scattering law and fission product yield for the first time. Light charged-particle and photon induced reaction data were also included for the first time as the JENDL general purpose file.
and 
shell gap for Ti and V by the first high-precision multireflection time-of-flight mass measurements at BigRIPS-SLOWRI飯村 俊*; Rosenbusch, M.*; 高峰 愛子*; 角田 佑介*; 和田 道治*; Chen, S.*; Hou, D. S.*; Xian, W.*; 石山 博恒*; Yan, S.*; et al.
Physical Review Letters, 130(1), p.012501_1 - 012501_6, 2023/01
The atomic masses of 
Sc, 
Ti, and 
V have been determined using the high-precision multireflection time-of-flight technique. The radioisotopes have been produced at RIKEN's Radioactive Isotope Beam Factory (RIBF) and delivered to the novel designed gas cell and multireflection system, which has been recently commissioned downstream of the ZeroDegree spectrometer following the BigRIPS separator. For Ti and V, the mass uncertainties have been reduced down to the order of 10 keV, shedding new light on the shell effect in Ti and V isotopes by the first high-precision mass measurements of the critical species 
Ti and 
V. With the new precision achieved, we reveal the nonexistence of the empirical two-neutron shell gaps for Ti and V, and the enhanced energy gap above the occupied 
p
orbit is identified as a feature unique to Ca. We perform new Monte Carlo shell model calculations including the d
and g
orbits and compare the results with conventional shell model calculations, which exclude the g and the d orbits. The comparison indicates that the shell gap reduction in Ti is related to a partial occupation of the higher orbitals for the outer two valence neutrons at 
.
余語 覚文*; Lan, Z.*; 有川 安信*; 安部 勇輝*; Mirfayzi, S. R.*; Wei, T.*; 森 隆人*; Golovin, D.*; 早川 岳人*; 岩田 夏弥*; et al.
Physical Review X, 13(1), p.011011_1 - 011011_12, 2023/01
被引用回数：0Neutrons are powerful tools for investigating the structure and properties of materials used in science and technology. Recently, laser-driven neutron sources (LDNS) have attracted the attention of different communities, from science to industry, in a variety of applications, including radiography, spectroscopy, security, and medicine. However, the laser-driven ion acceleration mechanism for neutron generation and for establishing the scaling law on the neutron yield is essential to improve the feasibility of LDNS. In this paper, we report the mechanism that accelerates ions with spectra suitable for neutron generation. We show that the neutron yield increases with the fourth power of the laser intensity, resulting in the neutron generation of 
in 
at a maximum, with 
Wcm
, 900 J, 1.5 ps lasers. By installing a "hand-size" moderator, which is specially designed for the LDNS, it is demonstrated that the efficient generation of epithermal (0.1-100 eV) neutrons enables the single-shot analysis of composite materials by neutron resonance transmission analysis (NRTA). We achieve the energy resolution of 2.3% for 5.19-eV neutrons 1.8 m downstream of the LDNS. This leads to the analysis of elements and isotopes within sub-
s times and allows for high-speed nondestructive inspection.
Maurer, C.*; Galmarini, S.*; Solazzo, E.*; Ku
mierczyk-Michulec, J.*; Bar
, J.*; Kalinowski, M.*; Schoeppner, M.*; Bourgouin, P.*; Crawford, A.*; Stein, A.*; et al.
Journal of Environmental Radioactivity, 255, p.106968_1 - 106968_27, 2022/12
2015, 2016年のモデル比較演習を経て、2019年に包括的なXe-133大気輸送モデル比較試験を企画した。欧米の医療用RI製造施設であるIREやCNLからの排出の影響が大きいヨーロッパと北米にある4つのCTBT国際モニタリングシステム局を対象とし、約30の参加モデルの結果の比較とアンサンブルを実施した。第2回ATMチャレンジの教訓により、参加者は事務局の指定する条件に基づいて計算を実施した。その結果、IREとCNLからの正確な日別スタック排出量を使用しても、拡散過程における誤差、残存排出源の適切な特性化、長いIMSサンプリング時間(12
24時間)のデメリットと相殺され、平均すればスコアの改善が見られないことが確認された。一方、任意のモデル計算結果を用いたアンサンブルを実施したところ、今回対象とした4つの観測所でのXe-133バックグラウンドを十分に予測できることが確認できた。有効なアンサンブルのサイズは5以下であった。
Ni
In
酒井 宏典; 徳永 陽; 神戸 振作; Zhu, J.-X.*; Ronning, F.*; Thompson, J. D.*; 小手川 恒*; 藤 秀樹*; 鈴木 康平*; 大島 佳樹*; et al.
Physical Review B, 106(23), p.235152_1 - 235152_8, 2022/12
被引用回数：0 パーセンタイル：0(Materials Science, Multidisciplinary)Ni置換系CeCoNi
Inについて、核四重極共鳴と核磁気共鳴(NQR/NMR)を用いて調べた。
=2.3Kの超伝導転移gは、Ni置換によって徐々に下がってゆき、
=0.25の時にゼロとなる。超格子を用いた密度関数計算によってNQRスペクトルの帰属を行い、スピン格子緩和率
が一様に抑えられ、反強磁性スピン揺らぎがNi置換によって弱められることを明らかにした。=0.25のとき、
が、
=2Kで極大を示すことがわかった。このことは、遍歴電子の反強磁性スピン揺らぎがネスティングによって打ち消し合っているとして理解できる。
飯田 一樹*; 樹神 克明; 稲村 泰弘; 中村 充孝; Chang, L.-J.*; 社本 真一
Scientific Reports (Internet), 12, p.20663_1 - 20663_7, 2022/12
被引用回数：0 パーセンタイル：0(Multidisciplinary Sciences)イルメナイトFeTiO
粉末サンプルのスピン励起を、飛行時間非弾性中性子散乱によって測定し、動的磁気ペア密度関数
を、動的磁気構造因子
からフーリエ変換によって初めて得ることに成功した。
neutron diffraction and electron microscopy studyZheng, R.*; Gong, W.; Du, J.-P.*; Gao, S.*; Liu, M.*; Li, G.*; 川崎 卓郎; Harjo, S.; Ma, C.*; 尾方 成信*; et al.
Acta Materialia, 238, p.118243_1 - 118243_15, 2022/10
被引用回数：3 パーセンタイル：86.42(Materials Science, Multidisciplinary)Grain refinement can lead to the strengthening of metallic materials according to the Hall-Petch relationship. However, our recent results suggested that grain boundary sliding is the dominant deformation mode in bulk ultrafine grained (UFG) pure Mg at room temperature, leading to softening. Here, for the first time, we report that the Hall-Petch strengthening can be regained in bulk UFG pure Mg at cryogenic temperature. At 77K, the UFG pure Mg with a mean grain size of 0.6 m exhibited ultrahigh tensile yield strength and ultimate tensile strength of 309 MPa and 380 MPa, respectively. Combined neutron diffraction and electron microscopy investigation indicated that residual dislocation structures and deformation twins hardly formed in the UFG specimen during tensile test at 298K. In contrast, fast accumulation of lattice defects and remarkable reorientation were evident at 77K, suggesting that the grain-boundary-mediated process was suppressed and the plastic deformation was dominated by dislocation slip and deformation twinning. In addition, all the pure Mg specimens exhibited pronounced strain hardening at 77 K, which was mainly attributed to the suppressed grain boundary sliding and dynamic recovery. The mean dislocation density and relative fractions of dislocations with various Burgers vectors of the UFG specimen deformed at 77K were determined quantitatively from neutron diffraction data.
保田 諭; 松島 永佳*; 原田 健児*; 谷井 理沙子*; 寺澤 知潮; 矢野 雅大; 朝岡 秀人; Gueriba, J. S.*; Di
o, W. A.*; 福谷 克之
ACS Nano, 16(9), p.14362 - 14369, 2022/09
被引用回数：1 パーセンタイル：0(Chemistry, Multidisciplinary)水素同位体である重水素は、半導体産業や医薬品開発に必須な材料であることから、重水素の高効率かつ低コストでの濃縮分離技術の開発は重要である。本研究では、グラフェンとパラジウム薄膜からなるヘテロ電極触媒を開発し、固体高分子形電気化学水素ポンピング法に適用することで高い分離能をもつ重水素濃縮デバイスの開発を行った研究について報告する。その結果、印加電圧が大きくなるにつれ分離能の指標となるH/D値が小さくなる明瞭な電位依存性が観察された。観察されたH/Dの電圧依存性について理論計算により検証した結果、印加電圧が小さい場合、水素イオンと重水素イオンがグラフェン膜透過の活性化障壁を量子トンネル効果により透過することで大きなH/D分離能が発現すること、印加電圧が大きくなると活性化障壁を乗り越えて反応が進行するためH/D値が減少することが示された。以上、グラフェンの水素同位体イオンの量子トンネル効果を利用することで高いH/D分離能を有する水素同位体分離デバイス創製の設計指針を得た。
Kim, G.*; Im, S.*; Jee, H.*; Suh, H.*; Cho, S.*; 兼松 学*; 諸岡 聡; 小山 拓*; 西尾 悠平*; 町田 晃彦*; et al.
Cement and Concrete Research, 159, p.106869_1 - 106869_17, 2022/09
被引用回数：2 パーセンタイル：75.4(Construction & Building Technology)This study explored the effect of M-S-H formation on the local atomic arrangements and mechanical properties of C-S-H. The elastic moduli of the samples were calculated using shifted atomic distances (r) and d-spacings (d) acquired by applying an external load on the pastes during X-ray scattering experiments. The experimental results indicated that the crystal structure of C-S-H remained intact with MgCl
addition. At the highest Mg/Si ratio (Ca/Si = 0.6, Mg/Si = 0.2), change in the dominant phase occurred from C-S-H to M-S-H because the low pH environment hindered the formation of C-S-H and facilitated the formation of M-S-H. The elastic modulus decreased with increasing Mg/Si ratio up to 0.1 owing to both C-S-H destabilization and low M-S-H content in the samples. Conversely, the elastic modulus increased in the paste synthesized with the highest Mg/Si ratio because considerable M-S-H had formed, which exhibited a higher elastic modulus than C-S-H.
Wang, Q.*; Hu, Q.*; Zhao, C.*; Yang, X.*; Zhang, T.*; Ilavsky, J.*; Kuzmenko, I.*; Ma, B.*; 舘 幸男
International Journal of Coal Geology, 261, p.104093_1 - 104093_15, 2022/09
被引用回数：1 パーセンタイル：0(Energy & Fuels)To understanding the spatial heterogeneity of mineral and pore structure variations in fine-grained shale, microscale X-ray fluorescence (micro-XRF) mapping, (ultra-) small-angle X-ray scattering [(U)SAXS] and wide-angle X-ray scattering were applied for two samples from a piece of Eagle Ford Shale in South Texas. Thin section petrography and field emission-scanning electron microscopy, X-ray diffraction (XRD), total organic carbon, and pyrolysis were also utilized to investigate the potential spatial heterogeneity of pore types, mineral and organic matter compositions for both samples. Overall, the siliceous-carbonate mineral contents in these carbonate-rich Eagle Ford Shale vary between laminations at mm scales. By analyzing six selected sub-samples on each of two samples with X-ray scattering and XRD techniques, nm-sized pores are mainly interparticle ones in the higher calcite regions, where the porosity is also relatively lower, while the lower calcite regions consist of both interparticle and intraparticle pore types with higher porosity. Finally, the micro-XRF and (U)SAXS are combined to generate porosity distribution maps to provide more insights about its heterogeneity related to the laminations and fractures at our observational scales.
Xia, C.-J.*; 丸山 敏毅; 安武 伸俊*; 巽 敏隆*
Physical Review D, 106(6), p.063020_1 - 063020_14, 2022/09
被引用回数：1 パーセンタイル：0.01(Astronomy & Astrophysics)We study nuclear pasta structures at high temperatures within a relativistic mean field model and Thomas-Fermi approximation. Typical structures (droplet, rod, slab, tube, and bubble) are obtained, which form various crystalline configurations. The properties of those nuclear pastas are examined in a three-dimensional geometry with reflection symmetry, where the optimum lattice constants are fixed minimizing the free energy under spherical or cylindrical approximations for Wigner-Seitz cells. For fixed densities and temperatures, the differences of the free energies per baryon for various shapes and lattice structures are typically on the order of tens of keV, suggesting the coexistence of those structures. If we further increase temperature, eventually the non-uniform structures of nuclear pasta become unstable and are converted into uniform nuclear matter. The phase diagrams of nuclear matter are estimated, which is useful for understanding the various phenomena in neutron stars.
; SR studies and charge-spin percolation modelSheng, Q.*; 金子 竜也*; Yamakawa, Kohtaro*; Guguchia, Z.*; Gong, Z.*; Zhao, G.*; Dai, G.*; Jin, C.*; Guo, S.*; Fu, L.*; et al.
Physical Review Research (Internet), 4(3), p.033172_1 - 033172_14, 2022/09
A pyrite system NiS
Se exhibits a bandwidth controlled Mott transition via (S,Se) substitutions in a two-step process: the antiferromagnetic insulator (AFI) to antiferromagnetic metal (AFM) transition at 
0.45 followed by the AFM to paramagnetic metal (PMM) transition at 1.0. Among a few other Mott systems which exhibit similar two-step transitions, Ni(S,Se) is of particular interest because a large intermediate AFM region in the phase diagram would provide unique opportunities to study the interplay between the spin and charge order. By comparing and combining our muon spin relaxation studies and previous neutron scattering studies, here we propose a picture where the spin order is maintained by the percolation of "nonmetallic" localized and dangling Ni moments surrounded by S, while the charge transition from AFI to AFM is caused by the percolation of the conducting paths generated by the Ni-Se-Ni bonds.
Yakushev, A.*; Lens, L.*; D
llmann, Ch. E.*; Khuyagbaatar, J.*; J
ger, E.*; Krier, J.*; Runke, J.*; Albers, H. M.*; 浅井 雅人; Block, M.*; et al.
Frontiers in Chemistry (Internet), 10, p.976635_1 - 976635_11, 2022/08
被引用回数：4 パーセンタイル：57.86(Chemistry, Multidisciplinary)114番元素フレロビウム(Fl)は現在その化学的性質が研究されている最も重い元素である。Flに関する最初の化学実験では、Flは貴ガス的な性質を持つ元素であると報告された。一方、2番目の研究では、Flは揮発性金属の性質を示すと報告された。より信頼性の高い結論を得るため、我々は更なる実験的研究を行い、二酸化ケイ素と金表面におけるFlの吸着挙動を調べた。その結果、Flは揮発性金属の水銀よりも高い揮発性と低い反応性を示し、一方、貴ガスのラドンよりは反応性が高いことを明らかにした。
青木 大*; 酒井 宏典; Opletal, P.; 常盤 欣文; 石塚 淳*; 柳瀬 陽一*; 播磨 尚朝*; 仲村 愛*; Li, D.*; 本間 佳哉*; et al.
Journal of the Physical Society of Japan, 91(8), p.083704_1 - 083704_5, 2022/08
被引用回数：6 パーセンタイル：94.33(Physics, Multidisciplinary)de Haas-van Alphen oscillation was successfully observed in an unconventional superconductor UTe using high-quality single crystals. From this observation, Fermi surfaces of this compound were determined to be cylinders elongated along the c-direction, in consistent with theoretical expectation. However, the extremely large cyclotron effective masses ranging 32 to 57 m
, in consistent with the electronic specific heat, far exceed calculated values.
decay of the 8
isomer in 
UZhang, M. M.*; Tian, Y. L.*; Wang, Y. S.*; Zhang, Z. Y.*; Gan, Z. G.*; Yang, H. B.*; Huang, M. H.*; Ma, L.*; Yang, C. L.*; Wang, J. G.*; et al.
Physical Review C, 106(2), p.024305_1 - 024305_6, 2022/08
被引用回数：1 パーセンタイル：67.14(Physics, Nuclear)The extremely neutron-deficient even-even uranium isotopes U were produced in the complete-fusion reactions induced by impinging 
Ar and Ca ions on 
W targets. Fusion evaporation residues were separated in flight by the gas-filled recoil separator SHANS (Spectrometer for Heavy Atoms and Nuclear Structure) and subsequently identified using the recoil--correlation method. In this paper, we report on new -decay activities with 
keV for 
U and 
keV for 
U, which decay from the 8 isomeric states of U into the 2 states of their daughter nuclei 
Th, respectively. The new results extend the systematics of the -decay fine structure for the 
= 124 and 126 even-even isotones.
Bateman, K.*; 村山 翔太*; 花町 優次*; Wilson, J.*; 瀬田 孝将*; 天野 由記; 久保田 満*; 大内 祐司*; 舘 幸男
Minerals (Internet), 12(7), p.883_1 - 883_20, 2022/07
被引用回数：0 パーセンタイル：0.02(Geochemistry & Geophysics)The construction of a repository for geological disposal of radioactive waste will include the use of cement-based materials. Following closure, groundwater will saturate the repository and the extensive use of cement will result in the development of a highly alkaline porewater, pH 
12.5; this fluid will migrate into and react with the host rock. The chemistry of the fluid will evolve over time, initially high [Na] and [K], evolving to a Ca-rich fluid, and finally returning to the groundwater composition. This evolving chemistry will affect the long-term performance of the repository, altering the physical and chemical properties, including radionuclide behaviour. Understanding these changes forms the basis for predicting the long-term evolution of the repository. This study focused on the determination of the nature and extent of the chemical reaction, as well as the formation and persistence of secondary mineral phases within a granite, comparing data from sequential flow experiments with the results of reactive transport modelling. The reaction of the granite with the cement leachates resulted in small changes in pH and the precipitation of calcium aluminum silicate hydrate (C-(A-)S-H) phases of varying compositions, of greatest abundance with the Ca-rich fluid. As the system evolved, secondary C-(A-)S-H phases re-dissolved, partly replaced by zeolites. This general sequence was successfully simulated using reactive transport modelling.
Zarazovski, M.*; Pistra, V.*; Lauerova, D.*; Obermeier, F.*; Mora, D.*; Dubyk, Y.*; Bolinder, T.*; Cueto-Felgueroso, C.*; Szavai, S.*; Dudra, J.*; et al.
Proceedings of ASME 2022 Pressure Vessels and Piping Conference (PVP 2022) (Internet), 11 Pages, 2022/07
The APAL (Advanced Pressurized Thermal Shock (PTS) Analysis for Long-Term Operation (LTO)) project was launched in October 2020 for four years with funding from the European Union's HORIZON 2020 program. Within APAL, an extensive literature review was performed and experience with defining the state-of-the-art of the Warm Pre-Stress (WPS) effect, which has an impact on the reactor pressure vessel (RPV) brittle fracture margin in both deterministic and probabilistic terms, was collected. To gather the worldwide experience of the WPS approaches and models, a comprehensive questionnaire was developed followed by each APAL partner response. It mainly focused on the following aspects: collection of existing WPS approaches and models implemented in standards and rules for RPV brittle fracture assessment; identification of the WPS issues; collection and analysis of the existing experimental data. This work describes worldwide experience and best practice of the WPS and its application for the RPV integrity assessment. The paper's conclusions are also focused on the recommendations for dealing with WPS issues.
Walter, H.*; Colonna, M.*; Cozma, D.*; Danielewicz, P.*; Ko, C. M.*; Kumar, R.*; 小野 章*; Tsang, M. Y. B*; Xu, J.*; Zhang, Y.-X.*; et al.
Progress in Particle and Nuclear Physics, 125, p.103962_1 - 103962_90, 2022/07
被引用回数：17 パーセンタイル：97.47(Physics, Nuclear)原子核-原子核衝突や原子核の状態方程式の研究において、反応計算モデルは重要なツールとなり、世界中で開発が進んでいる。本論文は、原子力機構のJQMD-2.0を含め、現在開発中の複数のコード開発者の協力により、これらコードを同じ条件で比較することで共通点や差異を明らかにしたプロジェクトTransport Model Evaluation Project (TMEP)を総括したものである。参加したコードはBoltzmann-Uehling-Uhlenbeck(BUU)法に基づく13のコードと、Quantum Molecular Dynamics (QMD)法に基づく12のコードであった。プロジェクトでは、Au原子核同士を衝突させてその終状態を観測する現実的な計算や、一辺が640nmの箱に核子を詰めて時間発展させる仮想的な計算を行った。その結果、BUU法コードとQMD法コードは計算原理が異なるため、計算の設定に関係なく系統的な差異が生じることが明らかになった。その一方で、同じ方法を採用するコード間の比較では、時間発展を細かく計算することでコード間の差は埋まっていき、一定の収束値を持つことが示された。この結果は今後開発される同分野のコードのベンチマークデータとして有用なものであるだけでなく、原子核基礎物理学の実験や理論研究の標準的な指針としても役に立つことが期待される。
Tang, J.*; Seo, O.*; Rivera Rocabado, D. S.*; 小板谷 貴典*; 山本 達*; 難波 優輔*; Song, C.*; Kim, J.*; 吉越 章隆; 古山 通久*; et al.
Applied Surface Science, 587, p.152797_1 - 152797_8, 2022/06
被引用回数：4 パーセンタイル：91.83(Chemistry, Physical)水素貯蔵材料として重要な立方体形状Pdナノ粒子の水素吸収と拡散メカニズムをX線光電子分光とDFT計算を用いて調べた。表面領域では粒子の大きさによらず、ほぼ同様の水素吸収挙動を示した。四面体サイトよりも八面体サイトの水素占有率が大きいことがわかった。表面の乱れによってPd-H結合が弱くなるため、小さいサイズのPdナノ粒子に吸収された水素原子は、より活発に粒子内部に拡散することが分かった。これが低水素圧での水素吸着に重要な役割を果たしている。
