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増田 啓人*; 山根 結太*; 土肥 昂尭*; 山崎 匠*; Modak, R.*; 内田 健一*; 家田 淳一; Kl
ui, M.*; 高梨 弘毅; 関 剛斎*
Advanced Science (Internet), 12(48), p.e14598_1 - e14598_9, 2025/12
被引用回数：1 パーセンタイル：27.91(Chemistry, Multidisciplinary)Current-induced domain-wall motion (CIDWM) in a synthetic antiferromagnet is a key phenomenon for developing potential high-density-packed magnetic domain-wall memory with fast operation. Here, we report CIDWM in the antiferromagnetically-coupled two Co layers through the Ir interlayer sandwiched by the two Pt layers: Pt/Co/Ir/Co/Pt. The top and bottom Pt layers play a role for generating the spin current coming from the spin Hall effect, which gives rise to the dual spin-orbit torque (SOT) acting on the perpendicular magnetizations of the Co layers. Although a simple argument would predict that SOTs from top and bottom Pt layers cancel each other out, the dual SOT nucleates a reversed magnetic domain and drives the CIDWM effectively at current density of the order of 10
A m
. This study also examines the effect of antisymmetric interlayer exchange coupling (AIEC) on CIDWM. We find a positive correlation between the magnitude of AIEC and the domain wall velocity whereas the current density required for nucleating the reversed domain shows a negative correlation with the magnitude of AIEC. These facts suggest that the existence of AIEC improves the performance of CIDWM. Our results provide a new avenue to design SOT domain wall devices based on a synthetic antiferromagnet.
松永 佳大*; 相澤 広記*; 浅森 浩一; 小川 大輝*; 宇津木 充*; 吉村 令慧*; 山崎 健一*; 内田 和也*; 松島 健*; 井上 智裕*; et al.
Tectonophysics, 915, p.230880_1 - 230880_11, 2025/11
被引用回数：4 パーセンタイル：75.70(Geochemistry & Geophysics)We estimated the resistivity structure in the region of the 1997 Northwestern Kagoshima earthquake doublet (March 26, Mw6.1; May 13, Mw6.0) by dense magnetotelluric (MT) observations to investigate the influence of low-resistivity zones on the initiation and termination of large inland earthquake ruptures. In addition to MT data from previous studies, we acquired new broadband MT and telluric data at 42 sites. With a total of 86 sites in approximately 50 km 
50 km area, we constructed a high-resolution resistivity structure through 3-D inversion. A comparison between the slip distribution and resistivity structure showed that the rupture of the mainshock in March initiated at the western edge of a low-resistivity zone, propagated westward (with a maximum slip of 0.8 m), and was ultimately arrested by another low-resistivity zone. Based on geological structures and 
He/
He ratios in hot springs, we suggest that magma-derived fluids, located beneath a shallow, low-permeability smectite-rich zone and granodiorite, contributed to the initiation of the mainshock rupture. Another smectite-rich zone, along with underlying high pore pressure fluids, played a role in arresting the rupture. The rupture of the mainshock in May initiated at the edge of another low-resistivity zone and propagated in two directions (with a maximum slip of 0.4 m): one along the edge of the low-resistivity zone and the other toward the low-resistivity zone, before finally stopping within the low-resistivity zone. Our findings are consistent with those from the 2016 Kumamoto earthquake (M7.3), supporting the idea that resistivity structures can help assess the spatial potential of large inland earthquakes.
石川 諒尚; 瀬川 麻里子; 藤 暢輔; 渡辺 賢一*; 増田 明彦*; 松本 哲郎*; 山崎 淳*; 吉橋 幸子*; 瓜谷 章*; 原野 英樹*
Journal of Radiation Research (Internet), 66(5), p.563 - 569, 2025/09
被引用回数：1 パーセンタイル：45.02(Biology)An optical fiber-based neutron detector is a real-time neutron monitor for an intense neutron field. A small piece of neutron scintillator, such as Ce-doped lithium glass (Li-glass), used in the detector has a random shape with a grain size of 200-400 
m. This causes shape-dependent effects on the detector response. However, it is difficult to control or clarify the micro shape due to its small size. Here we propose a technique to obtain the fine structure of a small piece of the scintillator using a microcomputed tomography (CT) system. To verify accuracy, the mass estimated based on the volume extracted from the obtained CT image was compared to the mass measured in advance using an electronic balance. In the obtained CT images, the fine shape of the small piece of Li-glass was clearly visible, and no false signals from the surrounding components were observed. The estimated mass was in good agreement with the measured value, however, a slight underestimation was observed when the total number of projection images was 2000. This was mitigated by increasing the number of projection images, and the difference between the estimated and measured mass was 1.6% when the number of the projection images was 3141. This was equivalent to the uncertainty of the measured mass. The proposed technique will be useful when high accuracy is needed, such as for medical applications.
山崎 匠*; 平井 孝昌*; 八木 貴志*; 山下 雄一郎*; 内田 健一*; 関 剛斎*; 高梨 弘毅
Physical Review Applied (Internet), 21(2), p.024039_1 - 024039_11, 2024/02
被引用回数：8 パーセンタイル：58.28(Physics, Applied)This study presents a measurement method for determining the figure of merit for transverse thermoelectric conversion in thin-film forms. Leveraging the proposed methodology, we comprehensively investigate the transverse thermoelectric coefficient, in-plane electrical conductivity, and out-of-plane thermal conductivity in epitaxial and polycrystalline Fe/Pt metallic multilayers.
山本 風海; 金正 倫計; 林 直樹; Saha, P. K.; 田村 文彦; 山本 昌亘; 谷 教夫; 高柳 智弘; 神谷 潤一郎; 菖蒲田 義博; et al.
Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09
被引用回数：10 パーセンタイル：74.14(Nuclear Science & Technology)J-PARC 3GeVシンクロトロン(RCS)は、最大1MWの大強度ビームを25Hzという早い繰り返しで中性子実験及び下流の主リングシンクロトロンに供給することを目的に設計された。2007年の加速器調整運転開始以降、RCSではビーム試験を通じて加速器の設計性能が満たされているかの確認を進め、必要に応じてより安定に運転するための改善を行ってきた。その結果として、近年RCSは1MWのビーム出力で連続運転を行うことが可能となり、共用運転に向けた最後の課題の抽出と対策の検討が進められている。本論文ではRCSの設計方針と実際の性能、および改善点について議論する。
寺阪 祐太; 渡辺 賢一*; 瓜谷 章*; 山崎 淳*; 佐藤 優樹; 鳥居 建男; 若井田 育夫
Journal of Nuclear Engineering and Radiation Science, 7(4), p.042002_1 - 042002_7, 2021/10
福島第一原子力発電所原子炉建物内の高線量率環境での線源分布測定への応用を目指し、波長スペクトルのアンフォールディング処理に基づく光ファイバーを用いた新しい一次元放射線分布測定法を開発した。開発した手法は光ファイバー内を伝搬する光の減衰量が波長依存であることを利用して、光ファイバー端から出力された波長スペクトルをアンフォールディングすることにより、光ファイバーへの放射線の入射位置を逆推定するというものである。この手法は光強度の積分値を利用するため、パルスカウンティングを行う放射線検出器を使用した場合に高線量率環境下で発生する計数損失や信号パイルアップの問題を回避することができる。本研究では紫外光源と
Sr/Y放射線源を用いた基礎実験を行い、線源位置検出の基本特性を確認した。
西村 昇一郎*; 鳥居 寛之*; 深尾 祥紀*; 伊藤 孝; 岩崎 雅彦*; 神田 聡太郎*; 川越 清以*; Kawall, D.*; 河村 成肇*; 黒澤 宣之*; et al.
Physical Review A, 104(2), p.L020801_1 - L020801_6, 2021/08
被引用回数：23 パーセンタイル：82.81(Optics)As a method to determine the resonance frequency, Rabi-oscillation spectroscopy has been developed. In contrast to conventional spectroscopy which draws the resonance curve, Rabi-oscillation spectroscopy fits the time evolution of the Rabi oscillation. By selecting the optimized frequency, it is shown that the precision is twice as good as conventional spectroscopy with a frequency sweep. Furthermore, the data under different conditions can be treated in a unified manner, allowing more efficient measurements for systems consisting of a limited number of short-lived particles produced by accelerators such as muons. We have developed a fitting function that takes into account the spatial distribution of muonium and the spatial distribution of the microwave intensity to apply this method to ground-state muonium hyperfine structure measurements at zero field. It was applied to the actual measurement data, and the resonance frequencies were determined under various conditions. The result of our analysis gives 
= 4 463 301.61 
0.71 kHz.
scattering length from 
photoproduction on the proton near the reaction threshold石川 貴嗣*; 藤村 寿子*; 深澤 宏司*; 橋本 亮*; He, Q.*; 本多 佑記*; 保坂 淳; 岩田 高広*; 甲斐田 俊*; 笠木 治郎太*; et al.
Physical Review C, 101(5), p.052201_1 - 052201_6, 2020/05
被引用回数：8 パーセンタイル：49.51(Physics, Nuclear)Photoproduction of the omega meson on the proton has been experimentally studied near the threshold. The total cross sections are determined at incident energies ranging from 1.09 to 1.15 GeV. The 1/2 and 3/2 spin-averaged scattering length 
and effective range 
between the CO meson and proton are estimated from the shape of the total cross section as a function of the incident photon energy: = (-0.97 
+ 
(0.07 
) fm and = (+2.78 
) + (-0.01 
) fm, resulting in a repulsive force. The real and imaginary parts for and are determined separately for the first time. A small 
-wave contribution does not affect the obtained values.
寺阪 祐太; 渡辺 賢一*; 瓜谷 章*; 山崎 淳*; 佐藤 優樹; 鳥居 建男; 若井田 育夫
Proceedings of International Youth Nuclear Congress 2020 (IYNC 2020) (Internet), 4 Pages, 2020/05
For the application in the measurement of the high dose rate hot spots inside the Fukushima Daiichi Nuclear Power Station buildings, we propose a wavelength-resolved type one-dimensional radiation distribution sensing method using plastic scintillating fiber (PSF). The proposing method estimates the incident position of radiation to the PSF by the unfolding of the wavelength spectrum output from the fiber edge using the fact that the attenuation length of scintillating light depends on the wavelength. By measuring the response function in advance, which defined as the wavelength spectrum measured at the fiber edge by the spectrometer with every transmission distance, the spectrum which can obtain when measured a certain radiation distribution can be expressed as the convolution of the response function. This method can avoid the problem of chance coincidence effect and signal pile-up, which occurs in the radiation detector with pulse counting mode under high dose rate field because this method measures the integrated light intensity. Through basic experiment using the ultraviolet irradiation source and Sr point source, basic properties of inverse estimation of irradiated position were confirmed, which showed that source position was reasonably estimated using the response function which obtained by the ultraviolet irradiation source in advance.
阿部 充志*; Bae, S.*; Beer, G.*; Bunce, G.*; Choi, H.*; Choi, S.*; Chung, M.*; da Silva, W.*; Eidelman, S.*; Finger, M.*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2019(5), p.053C02_1 - 053C02_22, 2019/05
被引用回数：196 パーセンタイル：99.40(Physics, Multidisciplinary)この論文はJ-PARCにおける、ミューオン異常磁気モーメント
と電気双極子モーメント(EDM) 
を測定する新しいアプローチを紹介する。我々の実験のゴールは、これまでと独立の、1/10の運動量と1/20のストレージリングを用いて、
とをこれまでにない精密な磁場で測定することである。さらに過去の実験との顕著な違いは、1/1000の横エミッタンスミューオンビーム(サーマルミューオンビーム)を用い、効率的なソレノイドへ縦入射し、ミューオンからの崩壊陽電子をトラッキングし、その小さな運動量ベクトルを求める点である。は統計精度450ppb、系統誤差70ppb、EDMについては
e
cmの精度で測定することを目標とする。
Strasser, P.*; 阿部 充志*; 青木 正治*; Choi, S.*; 深尾 祥紀*; 東 芳隆*; 樋口 嵩*; 飯沼 裕美*; 池戸 豊*; 石田 勝彦*; et al.
EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01
被引用回数：18 パーセンタイル：98.41(Quantum Science & Technology)High precision measurements of the ground state hyperfine structure (HFS) of muonium is a stringent tool for testing bound-state quantum electrodynamics (QED) theory, determining fundamental constants of the muon magnetic moment and mass, and searches for new physics. Muonium is the most suitable system to test QED because both theoretical and experimental values can be precisely determined. Previous measurements were performed decades ago at LAMPF with uncertainties mostly dominated by statistical errors. At the J-PARC Muon Science Facility (MUSE), the MuSEUM collaboration is planning complementary measurements of muonium HFS both at zero and high magnetic field. The new high-intensity muon beam that will soon be available at H-Line will provide an opportunity to improve the precision of these measurements by one order of magnitude. An overview of the different aspects of these new muonium HFS measurements, the current status of the preparation for high-field measurements, and the latest results at zero field are presented.
as anionic adsorptive photocatalyst杉田 剛; 小林 謙一*; 小林 健太郎*; 山崎 太樹*; 藤井 謙吾*; 板橋 英之*; 森 勝伸*
Journal of Photochemistry and Photobiology A; Chemistry, 356, p.71 - 80, 2018/04
被引用回数：6 パーセンタイル：12.23(Chemistry, Physical)光触媒は光照射のみで強力な酸化、還元反応を示す材料である。しかし、水中では反応目的物と触媒との接触効率が低いため、反応効率が著しく低下する。本研究では、水中でのアニオン性有機物質に対する吸着・分解反応性を向上させるため、アミノ基修飾型光触媒、及びそれを固定化した光触媒材料を調製し、その性能を評価した。その結果、光触媒を正電荷を持つアミノ基で修飾することにより、アニオン性有機物質の吸着・分解能力が向上することが明らかとなった。
中島 健次; 川北 至信; 伊藤 晋一*; 阿部 淳*; 相澤 一也; 青木 裕之; 遠藤 仁*; 藤田 全基*; 舟越 賢一*; Gong, W.*; et al.
Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12
J-PARC物質・生命科学実験施設の中性子実験装置についてのレビューである。物質・生命科学実験施設には23の中性子ビームポートがあり21台の装置が設置されている。それらは、J-PARCの高性能な中性子源と最新の技術を組み合わせた世界屈指の実験装置群である。このレビューでは、装置性能や典型的な成果等について概観する。
河地 有木; 小柳 淳*; 鈴井 伸郎; 石井 里美; 尹 永根; 山崎 治明; 岩崎 郁*; 小川 健一*; 藤巻 秀
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 93, 2013/01
We had employed the positron emitting tracer imaging system (PETIS) in combination with carbon-11- labeled carbon dioxide (CO) as the tracer gas. In the present study, we have developed a new method based on PETIS and CO to evaluate individual photosynthetic abilities of young seedlings planted collectively on a petri dish with agar culture medium and thus investigate the effect of genetic modification or treatment on plant biomass enhancement. We report for the first time a method based on the use of PETIS and tracer gas of CO for the quantitative and statistical evaluation of carbon fixation by small plant individuals. We plan to extend this method to the analysis of the relationship between the individual carbon fixation ability and gene expression, which is probably related to photosynthesis.
武田 全康; 山崎 大; 曽山 和彦; 丸山 龍治; 林田 洋寿; 朝岡 秀人; 山崎 竜也; 久保田 正人; 相澤 一也; 新井 正敏; et al.
Chinese Journal of Physics, 50(2), p.161 - 170, 2012/04
The construction of a new polarized neutron reflectometer is now in progress at the Materials and Life Science Experimental Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). MLF has the world's brightest pulsed neutron and muon sources (JSNS and MUSE). The user program of MLF has been already started in 2008, and now nine neutron and two muon spectrometers are in operation. Installation of the new reflectometer was expected to be completed in March 2011. However, the construction was interrupted by the massive earthquake hitting northeast Japan, including Tokai-mura where J-PARC is located. We expect to restart the user program of the new polarized neutron reflectometer at the beginning of next year (2012).
河地 有木; 鈴井 伸郎; 石井 里美; 山崎 治明; 岩崎 郁*; 小川 健一*; 藤巻 秀
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 93, 2012/01
Elucidation of carbon kinetics in a higher plant, in particular photosynthetic carbon dioxide (CO) fixation and photoassimilate translocation, is important from viewpoint of environmental reduction in the amounts of atmospheric CO and from an agricultural viewpoint of the growth and development of the plant body. Previously, we have reported that whole-plant imaging for studying the complete carbon kinetics involved in photosynthesis and subsequent photoassimilate translocation and unloading. It was achieved using a positron emitting tracer imaging system (PETIS) in combination with carbon-11-labeled carbon dioxide (CO) gas tracer. In this study, real-time carbon kinetics in leaves, roots and other organs of a soybean was analyzed by using the newly developed method.
C translocation using positron-emitting tracer imaging system河地 有木; 鈴井 伸郎; 石井 里美; 伊藤 小百合; 石岡 典子; 山崎 治明; 岩崎 郁*; 小川 健一*; 藤巻 秀
Nuclear Instruments and Methods in Physics Research A, 648(Suppl.1), p.S317 - S320, 2011/08
被引用回数：20 パーセンタイル：78.47(Instruments & Instrumentation)Elucidation of carbon kinetics in a plant is important from viewpoint of environmental reduction in the amounts of atmospheric carbon dioxide (CO) and from an agricultural viewpoint in terms of the growth and development of the plant body. In articular photosynthetic CO fixation and photoassimilate translocation are important topics for understanding the mechanisms underlying carbon kinetics. In this study, we have developed a method to investigate the carbon kinetics by using one of the most powerful radionuclide-based imaging techniques for plant study, that is, the positron emitting tracer imaging system (PETIS). Carbon-11-labeled carbon dioxide (CO) and PETIS enable video imaging of tracer dynamics of carbon fixation, photosynthesis, and translocation. Because of a large field of view (FOV) provided by the PETIS and the sufficiently small size of soybeans (
cultive Jack) that fit in the FOV, dynamic quantitative PETIS data of gradual changing in C activity and C distribution throughout the entire intact plant body after pulse-chase CO treatment is acquired. This indicates the successful imaging of CO photoassimilate translocation from the time of infusion into leafs to that of distribution of the whole plant body; further, carbon kinetics is analyzable to understand plant physiology and nutrition.
CO)河地 有木; 鈴井 伸郎; 石井 里美; 伊藤 小百合; 石岡 典子; 山崎 治明; 岩崎 郁*; 小川 健一*; 藤巻 秀
JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 101, 2011/01
Elucidation of carbon kinetics in a plant is important from viewpoint of environmental reduction in the amounts of atmospheric carbon dioxide (CO) and from an agricultural viewpoint in terms of the growth and development of the plant body. In particular photosynthetic CO fixation and photoassimilate translocation are important topics for understanding the mechanisms underlying carbon kinetics. In this study, we have developed a method to investigate the carbon kinetics by using one of the most powerful radionuclide-based imaging techniques for plant study, that is, the Positron Emitting Tracer Imaging System (PETIS) and carbon-11-labeled carbon dioxide (CO).
吉本 政弘; 植野 智晶; 富樫 智人; 豊川 良治; 竹田 修; 渡辺 真朗; 山崎 良雄; 山本 風海; 神谷 潤一郎; 高柳 智弘; et al.
IEEE Transactions on Applied Superconductivity, 18(2), p.301 - 305, 2008/06
被引用回数：1 パーセンタイル：12.52(Engineering, Electrical & Electronic)DC magnets are installed for beam injection and extraction at the RCS ring in J-PARC. The four steering magnets and two septum magnets are installed at injection line in order to adjust the beam injection point. A quadratic magnet, two steering magnet and two septum magnets are installed at dump line for the part of the beam with their charge not changed from H
to H
at the charge stripping foil. Two deflecting magnets to kick out the beam without exciting the kicker magnets and three septum magnets are installed at the extraction line. Up to now, the development of the DC magnets has been finished and the field measurements are being carried out by using the 3 dimensional hole-probe with 3-axias stage and the harmonic rotating coil.
吉本 政弘; 植野 智晶; 富樫 智人; 竹田 修; 金澤 謙一郎; 渡辺 真朗; 山崎 良雄; 神谷 潤一郎; 高柳 智弘; 倉持 勝也; et al.
IEEE Transactions on Applied Superconductivity, 18(2), p.297 - 300, 2008/06
被引用回数：4 パーセンタイル：30.07(Engineering, Electrical & Electronic)There are seven septum magnets for the beam injection and extraction at the RCS in J-PARC. In design of the septum magnets, the most important is that the magnetic leakage field outside the septum will disappear, but it is difficult in fact. In order to reduce the leakage field from the septum magnets at the beam orbit in the ring, the silicon steel sheets are set at the outside of the septum magnets as the magnetic shields. However sufficient spaces to set the thick magnetic shields are not securable at the divergent duct areas. Therefore the vacuum chambers are made by the magnetic stainless steel and the leakage fields in the chambers can be reduced. As results of the 3D field calculations by TOSCA, the magnetic leakage field can be suppressed to a few Gauss or less.
