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Miura, Daisuke*; Kumada, Takayuki; Sekine, Yurina; Motokawa, Ryuhei; Nakagawa, Hiroshi; Oba, Yojiro; Ohara, Takashi; Takata, Shinichi; Hiroi, Kosuke; Morikawa, Toshiaki*; et al.
Journal of Applied Crystallography, 54(2), p.454 - 460, 2021/04
Times Cited Count：0 Percentile：0.02(Chemistry, Multidisciplinary)We developed a spin-contrast-variation neutron powder diffractometry technique that extracts the structure factor of hydrogen atoms, namely, the contribution of hydrogen atoms to a crystal structure factor. Crystals of L-glutamic acid were dispersed in a dpolystyrene matrix containing 4-methacryloyloxy-2,2,6,6,-tetramethyl-1-piperidinyloxy (TEMPO methacrylate) to polarize their proton spins dynamically. The intensities of the diffraction peaks of the sample changed according to the proton polarization, and the structure factor of the hydrogen atoms was extracted from the proton-polarization dependent intensities. This technique is expected to enable analyses of the structures of hydrogen-containing materials that are difficult to determine with conventional powder diffractometry.
Kumada, Takayuki; Akutsu, Kazuhiro*; Oishi, Kazuki*; Morikawa, Toshiaki*; Kawamura, Yukihiko*; Sahara, Masae*; Suzuki, Junichi*; Miura, Daisuke*; Torikai, Naoya*
J-PARC 20-02, p.38 - 40, 2021/00
Tachi, Yukio; Sato, Tomofumi*; Akagi, Yosuke*; Kawamura, Makoto*; Nakane, Hideji*; Terashima, Motoki; Fujiwara, Kenso; Iijima, Kazuki
Science of the Total Environment, 724, p.138098_1 - 138098_11, 2020/07
Times Cited Count：5 Percentile：70.14(Environmental Sciences)To understand and predict radiocesium transport behaviors in the environment, highly contaminated sediments from Ukedo and Odaka rivers around the Fukushima Daiichi Nuclear Power Plant were investigated systematically focusing on key factors controlling radiocesium sorption and fixation, including particle size, clay mineralogy and organic matter.
=0 long-range magnetic order in centennialite CaCu
(OD)
Cl
0.6DO; A Spin-
perfect kagome antiferromagnet with 
-
-
Iida, Kazuki*; Yoshida, Hiroyuki*; Nakao, Akiko*; Jeschke, H. O.*; Iqbal, Y.*; Nakajima, Kenji; Kawamura, Seiko; Munakata, Koji*; Inamura, Yasuhiro; Murai, Naoki; et al.
Physical Review B, 101(22), p.220408_1 - 220408_6, 2020/06
Times Cited Count：6 Percentile：75.71(Materials Science, Multidisciplinary)Crystal and magnetic structures of the mineral centennialite CaCu(OD)Cl 0.6DO are investigated by means of synchrotron X-ray diffraction and neutron diffraction measurements complemented by density functional theory (DFT) and pseudofermion functional renormalization group (PFFRG) calculations. In CaCu(OD)Cl 0.6DO, Cu
ions form a geometrically perfect kagome network with antiferromagnetic . No intersite disorder between Cu and Ca ions is detected. CaCu(OD)Cl 0.6DO enters a magnetic long-range ordered state below 
= 7.2 K, and the =0 magnetic structure with negative vector spin chirality is obtained. The ordered moment at 0.3 K is suppressed to 0.58(2)
B. Our DFT calculations indicate the presence of antiferromagnetic and ferromagnetic superexchange couplings of a strength which places the system at the crossroads of three magnetic orders (at the classical level) and a spin- PFFRG analysis shows a dominance of =0 type magnetic correlations, consistent with and indicating proximity to the observed =0 spin structure. The results suggest that this material is located close to a quantum critical point and is a good realization of a -- kagome antiferromagnet.
RuO
proved by spin resonanceIida, Kazuki*; Kofu, Maiko; Suzuki, Katsuhiro*; Murai, Naoki; Kawamura, Seiko; Kajimoto, Ryoichi; Inamura, Yasuhiro; Ishikado, Motoyuki*; Hasegawa, Shunsuke*; Masuda, Takatsugu*; et al.
Journal of the Physical Society of Japan, 89(5), p.053702_1 - 053702_5, 2020/05
Times Cited Count：8 Percentile：87.06(Physics, Multidisciplinary)Kumada, Takayuki; Akutsu, Kazuhiro*; Oishi, Kazuki*; Morikawa, Toshiaki*; Kawamura, Yukihiko*; Sahara, Masae*; Suzuki, Junichi*; Torikai, Naoya*
Journal of Applied Crystallography, 52(5), p.1054 - 1060, 2019/10
Times Cited Count：1 Percentile：21.27(Chemistry, Multidisciplinary)We developed a technique of spin-contrast-variation neutron reflectometry (SCV-NR). Polarized-neutron reflectivity curves of film samples vary as a function of their proton-polarization P. The P-dependent reflectivity curves of a polystyrene film was precisely reproduced using a common set of structure parameters and the P-dependent neutron scattering length. The reflectivity curve of poly (styrene-block-isoprene) (PSPI) presented a shoulder attributed to holes with the depth corresponding to one period of periodic lamellae on the free surface only at a specific P. In this way, structural information about specific surfaces or interfaces can be obtained by controlling the P.
Kajimoto, Ryoichi; Ishikado, Motoyuki*; Kira, Hiroshi*; Kaneko, Koji; Nakamura, Mitsutaka; Kamazawa, Kazuya*; Inamura, Yasuhiro; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Murai, Naoki; et al.
Physica B; Condensed Matter, 556, p.26 - 30, 2019/03
Times Cited Count：2 Percentile：22.21(Physics, Condensed Matter)Yamamoto, Tomohiko; Iwasaki, Akihisa*; Kawamura, Kazuki*; Matsubara, Shinichiro*; Harada, Hidenori*
Proceedings of 2018 ASME Pressure Vessels and Piping Conference (PVP 2018), 8 Pages, 2018/07
To design fast reactor (FR) core components, seismic response must be evaluated in order to ensure structural integrity. Thus, a core seismic analysis method has been developed to evaluate 3D core vibration behavior considering fluid structure interaction and vertical displacements (rising). 1/1.5 scale 37 core element mock-ups hexagonal-matrix experiment was performed to validate the core elements vibration analysis code in three dimensions (REVIAN-3D). Based on the test data, the analysis model newly incorporated to respond to strong excitation was verified.
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Murai, Naoki; Kira, Hiroshi*; Nakatani, Takeshi; et al.
Journal of Physics; Conference Series, 1021(1), p.012030_1 - 012030_6, 2018/06
Times Cited Count：3 Percentile：95.16Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.
Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12
The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.
MoO
Iida, Kazuki*; Kajimoto, Ryoichi; Mizuno, Yusuke*; Kamazawa, Kazuya*; Inamura, Yasuhiro; Hoshikawa, Akinori*; Yoshida, Yukihiko*; Matsukawa, Takeshi*; Ishigaki, Toru*; Kawamura, Yukihiko*; et al.
Journal of the Physical Society of Japan, 86(6), p.064803_1 - 064803_6, 2017/06
Times Cited Count：1 Percentile：15.72(Physics, Multidisciplinary)Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Nakajima, Kenji; Kawamura, Seiko; Nakatani, Takeshi; et al.
JAEA-Conf 2015-002, p.319 - 329, 2016/02
Nakamura, Mitsutaka; Kawakita, Yukinobu; Kambara, Wataru; Aoyama, Kazuhiro; Kajimoto, Ryoichi; Nakajima, Kenji; Kawamura, Seiko; Ikeuchi, Kazuhiko*; Kikuchi, Tatsuya; Inamura, Yasuhiro; et al.
JPS Conference Proceedings (Internet), 8, p.036011_1 - 036011_6, 2015/09
The needs for inelastic neutron scattering experiments under the special sample environment such as strong magnetic field and high temperature are recently increasing. However, the unwanted scatterings originating from these devices affect the detection of weak inelastic signals. In order to overcome this problem we have developed an oscillating radial collimator specialized for the chopper spectrometer at Materials and Life Science Experimental Facility (MLF) in J-PARC. In this study, we will report the performances of newly-developed oscillating radial collimators both for 4SEASONS and AMATERAS.
Miyahara, Kaname; Yoshikawa, Hideki; Oi, Takao; Shibata, Masahiro; Sawada, Atsushi; Sasamoto, Hiroshi; Iijima, Kazuki; Maekawa, Keisuke; Kawamura, Makoto; Kato, Tomoko; et al.
JAEA-Review 2006-015, 29 Pages, 2006/03
JAEA-Review-2006-015.pdf:4.58MB
This report is to outline a 5-year plan of research and development (R&D) for performance assessment of geological disposal of high-level radioactive waste in JAEA. This 5-year plan is based on JAEA's mid-term plan which follows the R&D policy specified in "Framework for Nuclear Energy Policy" issued by Japan Atomic Energy Commission. Moreover, research plans for safety regulation issued by Nuclear Safety Commission of Japan should be taken into account. The contents of this 5-year plan follows a framework of R&D issues for performance assessment field established in "the R&D map", i.e. the mid and long term R&D plan for geological disposal of high-level radioactive waste, developed by JNC (predecessor of JAEA) and other relevant R&D organizations. In each research plan, objectives based on the necessity and the significance of the research plan are clarified in the section of "Objectives and the past progresses", with summarizing the progresses of H12: Project to establish the scientific and technical basis for HLW disposal in Japan (Second Progress Report), and H17: Development and management of the technical knowledge base for the geological disposal of HLW (H17 report). In addition, next five year plan is described in the section of "5-year plan (up to Fiscal year Heisei-22)".
Nakamura, Mitsutaka; Kawakita, Yukinobu; Kambara, Wataru; Aoyama, Kazuhiro; Yamauchi, Yasuhiro; Kajimoto, Ryoichi; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Inamura, Yasuhiro; Nakajima, Kenji; et al.
no journal, ,
In recent years, the need for neutron inelastic scattering experiments in special environments under the strong magnetic field and the high temperature is increasing. On the other hand, there is a problem that the unnecessary scattering originating from the sample environment devices affects the detection of weak inelastic signals. To solve this problem, we have been developing the radial collimator for chopper spectrometer at J-PARC. In this talk, we plan to introduce the performance evaluation results of our radial collimator.
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Suzuki, Junichi*; Nakajima, Kenji; Kawamura, Seiko; Nakatani, Takeshi; et al.
no journal, ,
no abstracts in English
Nakamura, Mitsutaka; Kawakita, Yukinobu; Kambara, Wataru; Yamauchi, Yasuhiro; Aoyama, Kazuhiro; Kajimoto, Ryoichi; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Inamura, Yasuhiro; Nakajima, Kenji; et al.
no journal, ,
Recently, there is a growing need for neutron inelastic scattering experiments under special sample environments such as strong magnetic field and high temperatures. However the unwanted scattering originating from the sample environment equipment adversely affect the detection of weak inelastic signal. In order to overcome these difficulties, we have developed the radial collimators for chopper spectrometers at J-PARC. In this report we will show the results of performance evaluation tests for radial collimators.
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Suzuki, Junichi*; Nakajima, Kenji; Kawamura, Seiko; et al.
no journal, ,
no abstracts in English
Terashima, Motoki; Tachi, Yukio; Sato, Tomofumi; Akagi, Yosuke*; Kawamura, Makoto*; Nakane, Hideji*; Fujiwara, Kenso; Iijima, Kazuki
no journal, ,
no abstracts in English
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Nakajima, Kenji; Kawamura, Seiko; Nakatani, Takeshi; et al.
no journal, ,
no abstracts in English
