Kajimoto, Ryoichi; Yokoo, Tetsuya*; Nakamura, Mitsutaka; Kawakita, Yukinobu; Matsuura, Masato*; Endo, Hitoshi*; Seto, Hideki*; Ito, Shinichi*; Nakajima, Kenji; Kawamura, Seiko
Physica B; Condensed Matter, 562, p.148 - 154, 2019/06
Kajimoto, Ryoichi; Yokoo, Tetsuya*; Matsuura, Masato*
JAEA-Review 2018-024, 78 Pages, 2019/01
The joint user meeting for the neutron spectrometers in the Materials and Life Science Experimental Facility (MLF) at J-PARC, "DIRECTION 2018", was held jointly by J-PARC MLF, KEK-IMSS, and CROSS. This meeting was purposed to encourage users' activities and collaborations between users and instruments on six beamlines BL01 (4SEASONS), BL02 (DNA), BL06 (VIN ROSE), BL12 (HRC), BL14 (AMATERAS), and BL23 (POLANO). In this meeting, 14 talks and 21 posters were presented, which reported recent research activities using the instruments, and the current status of the instruments and sample environments. This report compiles the presentation materials and their abstracts.
Kajimoto, Ryoichi; Yokoo, Tetsuya*; Kamazawa, Kazuya*; Nakamura, Mitsutaka; Kawamura, Seiko; Ito, Shinichi*; Nakajima, Kenji
JAEA-Review 2017-031, 107 Pages, 2018/02
The joint user meeting for four direct-geometry neutron spectrometers in the Materials and Life Science Experimental Facility (MLF) at J-PARC, "DIRECTION 2017", was held at the Ibaraki Quantum Beam Research Center building on October 16th - 17th, 2017. This meeting was purposed to encourage the user activities on the four instruments 4SEASONS (BL01), HRC (BL12), AMATERAS (BL14), and POLANO (BL23), and was jointly organized by J-PARC MLF, KEK-IMSS, and CROSS. In this meeting, recent research activities using these instruments were reported in addition to the current status of the instruments, the sample environments, and software. This report compiles the presentation materials and their abstracts.
Nakajima, 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.
Ibuka, Soshi*; Yokoo, Tetsuya*; Ito, Shinichi*; Kamazawa, Kazuya*; Nakamura, Mitsutaka; Imai, Motoharu*
Journal of Physics; Conference Series, 868(1), p.012017_1 - 012017_6, 2017/07
Spin wave dispersion of the metallic antiferromagnet MnPt was investigated just above the order-order transition temperature by using the inelastic neutron scattering technique. The spin wave dispersion at = 400 K along ,  and  directions was isotropic within the measurement accuracy. These results show that large reduction of the stiffness constant with increasing temperature, and indicate the itinerancy of the magnetic moments.
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
Seto, Hideki; Ito, Shinichi; Yokoo, Tetsuya*; Endo, Hitoshi*; Nakajima, Kenji; Shibata, Kaoru; Kajimoto, Ryoichi; Kawamura, Seiko; Nakamura, Mitsutaka; Kawakita, Yukinobu; et al.
Biochimica et Biophysica Acta; General Subjects, 1861(1), p.3651 - 3660, 2017/01
J-PARC, Japan Proton Accelerator Research Complex provides short pulse proton beam at a repetition rate 25 Hz and the maximum power is expected to be 1 MW. Materials and Life Science Experimental Facility (MLF) has 23 neutron beam ports and 21 instruments have already been operated or under construction / commissioning. There are 6 inelastic / quasi-elastic neutron scattering spectrometers and the complementary use of these spectrometers will open new insight for life science.
Ito, Shinichi*; Yokoo, Tetsuya*; Masuda, Takatsugu*; Yoshizawa, Hideki*; Soda, Minoru*; Ikeda, Yoichi*; Ibuka, Soshi*; Kawana, Daichi*; Sato, Taku*; Nambu, Yusuke*; et al.
JPS Conference Proceedings (Internet), 8, p.034001_1 - 034001_6, 2015/09
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Mizuno, Fumio; Nakajima, Kenji; Kawamura, Seiko; Yokoo, Tetsuya*; Nakatani, Takeshi; Maruyama, Ryuji; Soyama, Kazuhiko; et al.
Journal of the Physical Society of Japan, 80(Suppl.B), p.SB025_1 - SB025_6, 2011/01
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Mizuno, Fumio; Yokoo, Tetsuya*; Nakatani, Takeshi; Arai, Masatoshi; Fujita, Masaki*
Kotai Butsuri, 45(2), p.79 - 89, 2010/02
Inelastic neutron scattering measurement using multiple incident energies can drastically enhances the measurement efficiency. The article reviews the principle of this new technique and an example of the measurement using the chopper spectrometer 4SEASONS of the pulsed neutron experimental facility in Japan Proton Accelerator Research Complex (J-PARC).
Nakamura, Mitsutaka; Kajimoto, Ryoichi; Inamura, Yasuhiro; Mizuno, Fumio; Fujita, Masaki*; Yokoo, Tetsuya*; Arai, Masatoshi
Journal of the Physical Society of Japan, 78(9), p.093002_1 - 093002_4, 2009/09
We succeeded in experimentally demonstrating that a series of two-dimensional maps of a dynamical structure factor in momentum-energy space with multiple incident energies can be simultaneously obtained by one measurement. This method reduces the dead time of time-of-flight measurement, and thus it markedly increases the measurement efficiency. Our achievement realized using the Fermi chopper spectrometer 4SEASONS in J-PARC is expected to open up new possibilities of inelastic neutron scattering measurements.
Kajimoto, Ryoichi; Nakajima, Kenji; Nakamura, Mitsutaka; Soyama, Kazuhiko; Yokoo, Tetsuya*; Oikawa, Kenichi; Arai, Masatoshi
Nuclear Instruments and Methods in Physics Research A, 600(1), p.185 - 188, 2009/02
no abstracts in English
Nakamura, Mitsutaka; Arai, Masatoshi; Kajimoto, Ryoichi; Yokoo, Tetsuya*; Nakajima, Kenji; Krist, T.*
Journal of Neutron Research, 16(3-4), p.87 - 92, 2008/09
no abstracts in English
Kajimoto, Ryoichi; Yokoo, Tetsuya*; Kofu, Maiko*; Noda, Kohei*; Kuwahara, Hideki*
Journal of Physics and Chemistry of Solids, 68(11), p.2087 - 2090, 2007/11
EuYMnO shows an antiferromagnetic transition below K. A spontaneous ferroelectric polarization along appears below K. The direction of then switches to below K. To investigate the relation between and the magnetic structure (MS), we have performed a neutron diffraction study using EXCED diffractometer installed at KENS spallation neutron facility of KEK. Magnetic Bragg peaks with a wave vector (0,0.31,1) were observed. By comparing a magnetic Bragg peak whose scattering vector is almost parallel to and that with almost parallel to , we have succeeded in observing the change of the MS at the temperature () where appears and at where changes its polarization direction. Our observations can be interpreted as formation of a spiral spin structure and change of its easy plane in response to the change of the dielectric properties.
Kajimoto, Ryoichi; Yokoo, Tetsuya*; Nakajima, Kenji; Nakamura, Mitsutaka; Soyama, Kazuhiko; Ino, Takashi*; Shamoto, Shinichi; Fujita, Masaki*; Oyama, Kenji*; Hiraka, Haruhiro*; et al.
Journal of Neutron Research, 15(1), p.5 - 12, 2007/03
We are developing a new chopper-type neutron inelastic spectrometer 4SEASONS for the spallation neutron source at J-PARC. This spectrometer has middle energy resolution and two orders higher efficiency than the ones at ISIS for a single crystal measurement. With this spectrometer, we try to explore novel quantum phenomena, in particular, the mechanism of the high- superconductivity. The high flux at a sample is achieved by incorporating the well designed transport devices in addition to the high flux of the source. The energy resolution is estimated to be 5-6% at = 0. Furthermore, the most distinguishing feature of 4SEASONS is the availability of the repetition rate multiplication (RRM) method. The RRM method enables us to utilize many 's at the same time, which will increase the efficiency of the measurement more than five times and make the survey of 4D space of - much easier.
Arai, Masatoshi; Yokoo, Tetsuya*; Kajimoto, Ryoichi; Nakajima, Kenji; Shamoto, Shinichi; Yamada, Kazuyoshi*; Fujita, Masaki*; Ino, Takashi*; Soyama, Kazuhiko; Nakamura, Mitsutaka; et al.
JAEA-Review 2006-033, 58 Pages, 2006/11
A research project entitled "Development of the 4D Space Access Neutron Spectrometer (4SEASONS) and Elucidation of the Mechanism of Oxide High- Superconductivity" has started in 2005 (repr. by M. Arai). It is supported by MEXT, Grant-in-Aid for Specially Promoted Research and is going to last until fiscal 2009. The goal of the project is to elucidate the mechanism of oxide high- superconductivity by neutron scattering technique. For this purpose, we will develop an inelastic neutron scattering instrument 4SEASONS (4d SpacE AccesS neutrON Spectrometer) for the spallation neutron source in Japan Proton Accelerator Research Complex (J-PARC). The instrument will have 100 times higher performance than existing world-class instruments, and will enable detailed observation of anomalous magnetic excitations and phonons in a four-dimensional momentum-energy space. This report summarizes the progress in the research project in fiscal 2007.
Nakamura, Mitsutaka; Iwase, Hiroki; Arai, Masatoshi; Kartini, E.*; Russina, M.*; Yokoo, Tetsuya*; Taylor, J. W.*
Physica B; Condensed Matter, 385-386(1), p.552 - 554, 2006/11
The mechanism of high ionic conductivity in superionic glass constitute an unsolved problem in the field of science.Here we performed inelastic neutron scattering measurements of superionic glass system (AgI)(AgS)(AgPO) by using MARI spectrometer at ISIS, and found that the -dependence of inelastic intensity in the energy region from 1 to 3 meV of superionic phase glass shows an excess intensity above =1.8 compared with insulator phase one. Similar phenomena were also observed in another superionic glass (AgI)(AgPO) by using NEAT spectrometer at HMI with high resolution measurement. These results clearly suggest peculiar low energy vibrational excitations should be universal features of superionic glass.
Sasaki, Tomoyuki*; Yokoo, Tetsuya*; Katano, Susumu; Akimitsu, Jun*
Journal of the Physical Society of Japan, 74(1), p.267 - 270, 2005/01
no abstracts in English
Saito, Masahiro*; Okada, Noriko*; Nishibori, Eiji*; Takagiwa, Hiroyuki*; Yokoo, Tetsuya*; Nishi, Masakazu*; Kakurai, Kazuhisa; Kunii, Satoru*; Takata, Masaki*; Sakata, Makoto*; et al.
Journal of the Physical Society of Japan, 71(10), p.2369 - 2372, 2002/10
no abstracts in English
*; *; Yokoo, Tetsuya*; *; Akimitsu, Jun*; Katano, Susumu
Physica C, 263(1-4), p.344 - 348, 1996/00
no abstracts in English