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Zhang, X.-T.*; Xing, Y.-H.*; Yao, X.-P.*; 大湊 友也*; Zhang, L.*; 松尾 衛
Communications Physics (Internet), 8, p.103_1 - 103_8, 2025/03
被引用回数：0 パーセンタイル：0.00(Physics, Multidisciplinary)Spin pumping effect is a sensitive and well-established experimental method in two-dimensional (2D) magnetic materials. We propose that spin pumping effect can be a valuable probe for non-Fermi liquid (NFL) behaviors at the 2D interface of magnetic heterostructures. We show that the modulations of ferromagnetic resonance exhibit power-law scalings in frequency and temperature for NFL metals induced near a quantum critical point (QCP). At the Ising nematic QCP, we demonstrate that the enhanced Gilbert damping coefficient 
acquires negative power-law exponents in distinct frequency regimes. The exponents convey universal parameters inherited from the QCP and reflect the non- quasiparticle nature of the spin carriers in the NFL metal. At finite temperature, we show that the Gilbert damping mechanism is restored in the quantum critical regime and measures the temperature dependence of the correlation length.
U(
) evaluated with the CCONE code system湊 太志*; 岩本 修
Physical Review C, 110(5), p.054311_1 - 054311_14, 2024/11
被引用回数：0 パーセンタイル：0.00(Physics, Nuclear)A calculation system with CCONE code is newly developed to estimate not only independent and cumulative fission fragment yields but also prompt fission neutron, prompt fission gamma, decay heats, and delayed neutrons simultaneously. This system enables us to study a correlation between various fission observables. To determine lots of parameters in this system efficiently, a Gaussian process and a least square fitting are adopted We tested the calculation system through a thermal neutron-induced fission on U. In this paper, we demonstrate the performance of the parameter search method and show that experimental fission fragment yield data and other observables resulting from fission are reproduced well by the new calculation system.
Rochman, D.*; 湊 太志; 渡邉 友章; 他52名*
EPJ Nuclear Sciences & Technologies (Internet), 10, p.9_1 - 9_83, 2024/10
This paper summarized the efforts performed to understand decay heat estimation from existing spent nuclear fuel (SNF), under the auspices of the Working Party on Nuclear Criticality Safety (WPNCS) of the OECD Nuclear Energy Agency. Needs for precise estimations are related to safety, cost, and optimization of SNF handling, storage, and repository. The physical origins of decay heat (a more correct denomination would be decay power) are then introduced, to identify its main contributors (fission products and actinides) and time-dependent evolution. Due to limited absolute prediction capabilities, experimental information is crucial; measurement facilities and methods are then presented, highlighting both their relevance and our need for maintaining the unique current full-scale facility and developing new ones. The third part of this report is dedicated to the computational aspect of the decay heat estimation: calculation methods, codes, and validation. Different approaches and implementations currently exist for these three aspects, directly impacting our capabilities to predict decay heat and to inform decision-makers. Finally, recommendations from the expert community are proposed, potentially guiding future experimental and computational developments.
佐野 涼太郎*; 大湊 友也*; 松尾 衛
Physical Review Letters, 132(23), p.236302_1 - 236302_9, 2024/06
被引用回数：4 パーセンタイル：82.50(Physics, Multidisciplinary)We propose an ac intrinsic magnon spin Hall current driven by surface acoustic waves as a novel probe for such antiferromagnets. Our results pave the way towards mechanical detection and manipulation of the magnetic order in two-dimensional antiferromagnets.
林 博和; 湊 和生*
Electrochemistry (Internet), 92(4), p.043020_1 - 043020_5, 2024/04
被引用回数：0 パーセンタイル：0.00(Electrochemistry)NaCl-2CsCl溶融塩中のネプツニウムの挙動をサイクリックボルタンメトリ法やディファレンシャルパルスボルタンメトリ法などの電気化学的手法によって823から923Kにおいて測定した。NaCl-2CsCl溶融塩中において、Np
イオンは、LiCl-KCl共晶溶融塩中と同様に、Np
イオンを経てNpに還元されることを明らかにした。また、サイクリックボルタモグラムから、Np及びNpイオンの拡散係数を導出した。さらに、Np/Np
及びNp/Np酸化還元反応の式量電位が、E
(Np/Np
) = -3.353 + 7.67
10
T及びE(Np/Np) = -1.175 + 4.9910 T vs. Cl
/Cl
(V)であることを示し、Np及びNpイオンの活量係数を、NpCl
及びNpCl
の過冷却液体状態のギブス自由エネルギーの文献値を用いて導出した。
大湊 友也*; 山影 相*; 松尾 衛
Physical Review B, 109(12), p.L121405_1 - L121405_5, 2024/03
被引用回数：2 パーセンタイル：57.35(Materials Science, Multidisciplinary)We study a dynamical spin response of surface Majorana modes in a topological superconductor-magnet hybrid under microwave irradiation. We find a method to toggle between dissipative and nondissipative Majorana Ising spin dynamics by adjusting the external magnetic field angle and the microwave frequency. This reflects the topological nature of the Majorana modes, enhancing the Gilbert damping of the magnet, thereby providing a detection method for the Majorana Ising spins. Our findings illuminate a magnetic probe for Majorana modes, paving the path to innovative spin devices.
田中 翔也*; 西村 信哉*; 湊 太志
JAEA-Conf 2023-001, p.132 - 137, 2024/02
-process元素合成は、核図表の中性子過剰領域を通して重い元素を合成する。合成された元素は、太陽系や様々な金属量を持った星の中で観測されている。この元素合成では核分裂が重要な役割を演じているが、-processに関係するような中性子過剰領域にある原子核の核分裂を実験的に測定することは難しい。そのため我々は、Langevinモデルを用いて理論的に核分裂現象を解明することを目指している。特に我々は、中性子過剰核が質量数を増やしていくにつれて、非対称核分裂から対称核分裂へ遷移する現象に着目し、その核分裂収率を調べている。さらに、Langevinモデルで導出した核分裂収率と統計模型を用いて、即発中性子数を求める新しい試みも行った。
Ni静間 俊行*; Omer, M.; 早川 岳人*; 湊 太志*; 松葉 俊哉*; 宮本 修治*; 清水 則孝*; 宇都野 穣
Physical Review C, 109(1), p.014302_1 - 014302_7, 2024/01
被引用回数：3 パーセンタイル：84.33(Physics, Nuclear)Low-lying dipole states in the singly closed-shell nucleus Ni were studied via nuclear resonance fluorescence experiments using a quasi-monoenergetic, linearly polarized photon beam. The parity quantum numbers of the dipole states were determined by the intensity asymmetry of resonantly scattered 
-rays with respect to the polarization plane of the incident photon beam. The electric and magnetic dipole (E1 and M1) strengths at excitation energies between 5.9 and 9.8 MeV were obtained based on dipole strengths taken from literature. The E1 and M1 strength distributions were compared with large-scale shell-model predictions in the 
-shell using the SDPFSDG-MU interaction.
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：84.55(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.
Si and 
Ca湊 太志; 内藤 智也*; 岩本 修
Physical Review C, 107(5), p.054314_1 - 054314_10, 2023/05
被引用回数：2 パーセンタイル：43.87(Physics, Nuclear)Muon captures on nuclei have provided us a plenty of knowledge of nuclear properties. Recently, this nature attracts attention again in electronics, because it is argued that charged particle emissions following muon capture on silicon triggers non-negligible soft errors in semiconductors. To investigate the particle emissions from nuclear physics point of view, we develop a new approach using a microscopic model of muon capture and an up-to-date particle emission models. We paid attention to the muon capture rates, the particle emission spectra, and the multiplicities that have a close interrelation with each other, and found that the nuclear many-body correlation including two-particle two-hole excitations is a key to explain them simultaneously.
-edge for Ce in bauxites using transition-edge sensors; Implications for Ti-rich geological samplesLi, W.*; 山田 真也*; 橋本 直; 奥村 拓馬*; 早川 亮大*; 新田 清文*; 関澤 央輝*; 菅 大暉*; 宇留賀 朋哉*; 一戸 悠人*; et al.
Analytica Chimica Acta, 1240, p.340755_1 - 340755_9, 2023/02
被引用回数：11 パーセンタイル：65.24(Chemistry, Analytical)希土類元素は放射性元素であるアクチノイドのアナログ元素としてしばしば利用される。セリウム(Ce)は希土類元素の中でも+3価と+4価の両方をとり得る特別な元素である。環境試料中のCeの+3価と+4価の比を調べる手段としてX線吸収端近傍構造(XANES)が有力であったが、チタン濃度が高いと蛍光X線の干渉のために測定ができないという問題があった。本研究では、L
吸収端だけでなくL吸収端を調べ、さらに新しい検出器であるtransition-edge sensor (TES)を利用することでこれまでは測定が難しかった試料も測定可能にした。この結果は様々な環境試料に応用可能である。
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
被引用回数：213 パーセンタイル：99.99(Nuclear Science & Technology)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.
渡辺 証斗*; 湊 太志; 木村 真明*; 岩本 信之
JAEA-Conf 2022-001, p.103 - 108, 2022/11
We are working on a combination of nuclear reaction calculation code CCONE and machine learning libraries to generate nuclear data and improve their accuracy. The angular distributions of elastic and inelastic scatterings to the first excited state on 
Fe at several incident energies were calculated using CCONE, and the optical potential parameters were optimized to reproduce the experimental data by Bayesian optimization. The optimized parameters were the depth of the real volume and imaginary surface parts of the potential, their energy dependence, radius, and diffuseness. Using the obtained optical potential, we estimated the angular distributions at energies different from those used on the optimization, and found that the results were in good agreement with the experiment data. In this presentation, we will introduce these calculation results and future prospects.
渡辺 証斗*; 湊 太志; 木村 真明*; 岩本 信之
Journal of Nuclear Science and Technology, 59(11), p.1399 - 1406, 2022/11
被引用回数：1 パーセンタイル：14.04(Nuclear Science & Technology)In order to increase the efficiency of nuclear data evaluation, we have tested a combination of a nuclear reaction model and machine learning algorithm. We calculated nucleon-nucleus elastic scattering angular distributions by using the nuclear reaction model code, and optimized the potential parameters of an optical model to reproduce experimental data by means of the Bayesian optimization. We present optimization cases with the single parameter and two or more parameters, and show that our framework gives the angular distributions which are in good agreement with the observed ones.
国枝 賢; 古立 直也*; 湊 太志; 岩本 信之; 岩本 修
NEA/NSC/R(2020)4 (Internet), p.329 - 331, 2022/10
長寿命核分裂生成核種の核変換研究のために、新たな核データライブラリImPACT/LLFP-2018を開発した。測定データの少ない不安定核種の核反応断面積を推定するために、微視的理論に基づく核構造モデルをCCONEコードに導入した。また、理化学研究所で得られた最新の断面積測定データを用いて高エネルギー反応で重要な前平衡パラメータを決定した。開発したライブラリには
Se, 
Zr, 
Pdおよび
Csを含む160核種に対する中性子および陽子入射の断面積が200MeVをエネルギー上限に格納されている。さらに、既存の安定核種に対する測定値と比較することにより調査した結果、本ライブラリは他のライブラリと比べて実験データへの再現性が高いことが判った。
大湊 友也*; 山影 相*; 松尾 衛
Physical Review B, 106(16), p.L161406_1 - L161406_6, 2022/10
被引用回数：13 パーセンタイル：74.65(Materials Science, Multidisciplinary)We present a theoretical investigation of anisotropic superconducting spin transport at a magnetic interface between a 
-wave superconductor and a ferromagnetic insulator. Our formulation describes the ferromagnetic resonance modulations due to spin current generation depending on spin-triplet Cooper pair, including the frequency shift and enhanced Gilbert damping, in a unified manner. We find that the Cooper pair symmetry is detectable from the qualitative behavior of the ferromagnetic resonance modulation. Our theory paves the way toward anisotropic superconducting spintronics.
-decay half-lives within a Skyrme-Hartree-Fock-Bogoliubov energy density functional with the proton-neutron quasiparticle random-phase approximation and isoscalar pairing strengths optimized by a Bayesian method湊 太志; Niu, Z.*; Liang, H.*
Physical Review C, 106(2), p.024306_1 - 024306_13, 2022/08
被引用回数：12 パーセンタイル：84.55(Physics, Nuclear)For radioactive nuclear data, decay is one of the important information and is applied to various fields. However, some of the -decay data is not available due to experimental difficulties. From this respect, theoretically calculated results have been embedded in the -decay data to compensate the missing information. To calculate the -decay half-lives, a proton-neutron quasi-particle random phase approximation on top of a Skryme energy density functional is applied in this work. The isoscalar pairing strength that is sensitive to half-lives is estimated by a Bayesian neutral network (BNN). We found that the half-lives calculated with the BNN isoscalar pairing strengths could reproduce most of experimental data. We also studied that the predictive performance on new experimental data that are not used for the BNN training and found that they are reproduced well.
-wave superconductor/ferromagnetic insulator bilayer systems大湊 友也*; 山影 相*; 加藤 岳生*; 松尾 衛
Physical Review B, 105(20), p.205406_1 - 205406_7, 2022/05
被引用回数：13 パーセンタイル：72.26(Materials Science, Multidisciplinary)We investigate ferromagnetic resonance (FMR) modulation in -wave superconductor (SC)/ferromagnetic insulator (FI) bilayer systems theoretically. The modulation of the Gilbert damping in these systems reflects the existence of nodes in the -wave SC and shows power-law decay characteristics within the low-temperature and low-frequency limit. Our results indicate the effectiveness of the use of spin pumping as a probe technique to determine the symmetry of unconventional SCs with high sensitivity for nanoscale thin films.
大湊 友也*; 大上 能悟*; 松尾 衛
Physical Review B, 105(19), p.195409_1 - 195409_9, 2022/05
被引用回数：3 パーセンタイル：24.69(Materials Science, Multidisciplinary)Angular momentum conversion between mechanical rotation and the valley degree of freedom in 2D Dirac materials is investigated theoretically. Coupling between the valley and vorticity of dynamic lattice distortions is derived by applying the 
method to 2D Dirac materials with an inertial effect. Lattice strain effects are also incorporated. Valley transfer and valley-dependent carrier localization are predicted using the dynamic lattice distortions. The transport properties are found to be controllable, allowing the system to be insulating and to generate pulsed charge current. Our formalism offers a route toward mechanical manipulation of valley dynamics in 2D Dirac materials.
Yb for producing 
Lu with high radionuclide purity by Yb(
)Lu永井 泰樹*; 川端 方子*; 橋本 慎太郎; 塚田 和明; 橋本 和幸*; 本石 章司*; 佐伯 秀也*; 本村 新*; 湊 太志; 伊藤 正俊*
Journal of the Physical Society of Japan, 91(4), p.044201_1 - 044201_10, 2022/04
被引用回数：4 パーセンタイル：46.56(Physics, Multidisciplinary)近年、神経内分泌腫瘍を治療するための医療用RIとしてLuが注目されており、加速器施設で重陽子を濃縮Yb試料に照射し、高純度のLuを製造する方法が検討されている。ただし、Yb試料には様々な同位体が微量に含まれており、Lu以外のLu同位体が不純物として生成される。医療用として利用するLuは一定の純度が求められるため、定量的にLuの不純物を評価する手法が求められていた。本研究では、実験値を基に関与する全てのYb()Lu反応の断面積を決定し、粒子輸送計算コードPHITSと組み合わせることで、Yb試料が任意の組成比をもつ場合の各Lu同位体の生成量を推定する新しい手法を開発した。他に、天然組成のYb試料へ25MeV重陽子を照射した実験も行い、本手法の有効性を検証した。また、市販の濃縮Yb試料に照射した条件で計算を行い、重陽子のエネルギーを15MeVとすることで、純度99%以上のLu生成を達成できることを示した。開発した手法は、加速器を用いて高純度の医療用Luを製造する際、必要な濃縮Yb試料の同位体組成を議論する上で重要な役割を果たすものである。
