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He spin filter and small-angle X-ray scatteringRyoki, Akiyuki*; Watanabe, Fumi*; Okudaira, Takuya*; Takahashi, Shingo*; Oku, Takayuki; Hiroi, Kosuke; Motokawa, Ryuhei; Nakamura, Yo*
Journal of Chemical Physics, 160(11), p.114907_1 - 114907_9, 2024/03
Times Cited Count：0Kumada, Takayuki; Motokawa, Ryuhei; Oba, Yojiro; Nakagawa, Hiroshi; Sekine, Yurina; Micheau, C.; Ueda, Yuki; Sugita, Tsuyoshi; Birumachi, Atsushi; Sasaki, Miki; et al.
Journal of Applied Crystallography, 56(6), p.1776 - 1783, 2023/12
Times Cited Count：1 Percentile：65.66(Chemistry, Multidisciplinary)The combination of the existing position-sensitive photomultiplier and the 3He main detector with focusing devices, and the newly installed front detectors in SANS-J at JRR-3 covers small-angle neutron scattering signals in the range of the magnitude of the scattering vector Q from 0.002 to 6 nm-1 gaplessly with three standard device layouts. The installation of the front detector and a graphical user interface system largely improved the usability of SANS-J.
Tsuji, Hayato*; Nakahata, Masaki*; Hishida, Mafumi*; Seto, Hideki*; Motokawa, Ryuhei; Inoue, Takeru*; Egawa, Yasunobu*
Journal of Physical Chemistry Letters (Internet), 14(49), p.11235 - 11241, 2023/12
Times Cited Count：0 Percentile：0.01(Chemistry, Physical)Shibata, Motoki*; Nakanishi, Yohei*; Abe, Jun*; Arima, Hiroshi*; Iwase, Hiroki*; Shibayama, Mitsuhiro*; Motokawa, Ryuhei; Kumada, Takayuki; Takata, Shinichi; Yamamoto, Katsuhiro*; et al.
Polymer Journal, 55(11), p.1165 - 1170, 2023/11
Times Cited Count：1 Percentile：51.7(Polymer Science)Micheau, C.; Ueda, Yuki; Motokawa, Ryuhei; Bauduin, P.*; Girard, L.*; Diat, O.*
Langmuir, 39(31), p.10965 - 10977, 2023/07
Times Cited Count：0 Percentile：0(Chemistry, Multidisciplinary)
microphase separationIsozaki, Yuka*; Higashiharaguchi, Seiya*; Kaneko, Naoya*; Yamazaki, Shun*; Taniguchi, Tatsuo*; Karatsu, Takashi*; Ueda, Yuki; Motokawa, Ryuhei
Chemistry Letters, 51(6), p.625 - 628, 2022/06
Times Cited Count：2 Percentile：29.84(Chemistry, Multidisciplinary)He spin filter at a pulsed neutron sourceOkudaira, Takuya; Ueda, Yuki; Hiroi, Kosuke; Motokawa, Ryuhei; Inamura, Yasuhiro; Takata, Shinichi; Oku, Takayuki; Suzuki, Junichi*; Takahashi, Shingo*; Endo, Hitoshi*; et al.
Journal of Applied Crystallography, 54(2), p.548 - 556, 2021/04
Times Cited Count：3 Percentile：33.1(Chemistry, Multidisciplinary)Neutron polarization analysis (NPA) for small-angle neutron scattering (SANS) experiments using a pulsed neutron source was successfully achieved by applying a He spin filter as a spin analyzer for the scattered neutrons. The He spin filter covers a sufficient solid angle for performing SANS experiments, and the relaxation time of the He polarization is sufficient for continuous use over a few days, thus reaching the typical duration required for a complete set of SANS experiments. Although accurate evaluation of the incoherent neutron scattering, which is predominantly attributable to hydrogen atoms in samples, is practically difficult using calculations based on the sample elemental composition, the developed NPA approach with consideration of the influence of multiple neutron scattering enabled reliable decomposition of the SANS intensity distribution into the coherent and incoherent scattering components. To date, NPA has not been well established as a standard technique for SANS experiments at pulsed neutron sources. This work is anticipated to greatly contribute to the accurate determination of the coherent neutron scattering component for scatterers in various types of organic sample systems in SANS experiments at J-PARC.
Narita, Hirokazu*; Nicolson, R. M.*; Motokawa, Ryuhei; Ito, Fumiyuki*; Morisaku, Kazuko*; Goto, Midori*; Tanaka, Mikiya*; Heller, W. T.*; Shiwaku, Hideaki; Yaita, Tsuyoshi; et al.
Inorganic Chemistry, 58(13), p.8720 - 8734, 2019/07
Times Cited Count：14 Percentile：69.69(Chemistry, Inorganic & Nuclear)Motokawa, Ryuhei; Kobayashi, Toru; Endo, Hitoshi; Mu, J.*; Williams, C. D.*; Masters, A. J.*; Antonio, M. R.*; Heller, W. T.*; Nagao, Michihiro*
ACS Central Science, 5(1), p.85 - 96, 2019/01
Times Cited Count：47 Percentile：86.05(Chemistry, Multidisciplinary)Nakajima, Taro*; Inamura, Yasuhiro; Ito, Takayoshi*; Oishi, Kazuki*; Oike, Hiroshi*; Kagawa, Fumitaka*; Kikkawa, Akiko*; Taguchi, Yasujiro*; Kakurai, Kazuhisa*; Tokura, Yoshinori*; et al.
Physical Review B, 98(1), p.014424_1 - 014424_5, 2018/07
Times Cited Count：7 Percentile：34.59(Materials Science, Multidisciplinary)We investigated the phase-transition kinetics of magnetic skyrmion lattice (SkL) in MnSi by means of stroboscopic small-angle neutron scattering (SANS). Temporal evolutions of SANS patterns were measured with time resolution of 13 ms while sweeping temperature as fast as 50 Ks
. It turned out that the paramagnetic-to-SkL transition immediately occurs upon traversing the equilibrium phase boundary on the rapid cooling, whereas the SkL-to-conical transition can be kinetically avoided to realize the low-temperature metastable SkL with a long-range magnetic order. The formation of the metastable SkL was found to be strongly dependent not only on cooling rate, but also on magnetic eld and trajectory in the H-T phase diagram.
-butadiene) rubbersYamaguchi, Daisuke; Yuasa, Takeshi*; Sone, Takuo*; Tominaga, Tetsuo*; Noda, Yohei*; Koizumi, Satoshi*; Hashimoto, Takeji*
Macromolecules, 50(19), p.7739 - 7759, 2017/10
Times Cited Count：14 Percentile：48.82(Polymer Science)We elucidated the spatial distribution of filler particles in cross-linked poly(styrene--butadiene) rubbers (SBR) developed under a typical fillers/rubbers compounding process as one of dissipative structures formed under a stress field imposed on the given system. The dispersion state of the fillers in SBR was clarified on the basis of hierarchical structures consisting of five structure levels. More specifically, it has the following characteristics depending on the specific interactions: Small, compact clusters build up compact mass-fractal structures, while large, loose clusters build up open mass-fractal structures.
Narita, Hirokazu*; Suzuki, Tomoya*; Motokawa, Ryuhei
Nihon Kinzoku Gakkai-Shi, 81(4), p.157 - 167, 2017/04
Times Cited Count：17 Percentile：62.95(Metallurgy & Metallurgical Engineering)Noda, Yohei*; Koizumi, Satoshi*; Masui, Tomomi*; Mashita, Ryo*; Kishimoto, Hiromichi*; Yamaguchi, Daisuke; Kumada, Takayuki; Takata, Shinichi; Oishi, Kazuki*; Suzuki, Junichi*
Journal of Applied Crystallography, 49(6), p.2036 - 2045, 2016/12
Times Cited Count：19 Percentile：78.58(Chemistry, Multidisciplinary)Sekine, Yurina; Endo, Hitoshi*; Iwase, Hiroki*; Takeda, Shigeo*; Mukai, Sadaatsu*; Fukazawa, Hiroshi; Littrell, K. C.*; Sasaki, Yoshihiro*; Akiyoshi, Kazunari*
Journal of Physical Chemistry B, 120(46), p.11996 - 12002, 2016/11
Times Cited Count：11 Percentile：26.96(Chemistry, Physical)The detailed structure of a nanogel formed by self-association of cholesterol-bearing pullulans (CHP) was determined by contrast variation small-angle neutron scattering. The decomposition of scattering intensities into partial scattering functions of each CHP nanogel component, i.e., pullulan, cholesterol, and the cross-term between the pullulan and the cholesterol allows us to investigate the internal structure of the nanogel. The effective spherical radius of the skeleton formed by pullulan chains was found to be about 8.1 nm. In the CHP nanogel, there are about 19 cross-linking points where a cross-linking point is formed by aggregation of trimer cholesterol molecules with the spatially inhomogeneous distribution of the mass fractal dimension of 2.6. The average radius of the partial chains can also be determined to be 1.7 nm. As the result, the complex structure of the nanogels is coherently revealed at the nanoscopical level.
Motokawa, Ryuhei; Kobayashi, Toru; Endo, Hitoshi*; Ikeda, Takashi; Yaita, Tsuyoshi; Suzuki, Shinichi; Narita, Hirokazu*; Akutsu, Kazuhiro*; Heller, W. T.*
Journal of Nuclear Science and Technology, 53(8), p.1205 - 1211, 2016/08
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Motokawa, Ryuhei; Taniguchi, Tatsuo*; Kumada, Takayuki; Iida, You*; Aoyagi, Shota*; Sasaki, Yusuke*; Kori, Michinari*; Kishikawa, Keiki*
Macromolecules, 49(16), p.6041 - 6049, 2016/08
Times Cited Count：20 Percentile：58.6(Polymer Science)Oku, Takayuki; Suzuki, Junichi; Sasao, Hajime*; Yamada, Satoru; Furusaka, Michihiro*; Adachi, Tomohiro*; Shinohara, Takenao*; Ikeda, Kazuaki*; Shimizu, Hirohiko
Physica B; Condensed Matter, 356(1-4), p.126 - 130, 2005/02
Times Cited Count：11 Percentile：45.47(Physics, Condensed Matter)We have developed a magnetic neutron lens (MNL) based on a sextupole magnet. A neutron beam, which is incident to the sextupole magnet, either converges or diverges depending on the neutron spin state. Small-angle neutron scattering in focusing geometry (FSANS) was proposed to improve the q-resolution and/or measuring efficiency. The MNL is considered to be the most suitable focusing device for FSANS experiments using a polarized neutron beam, since it focuses the polarized neutron beam free from neutron attenuation and scattering by substances. Recently, we have developed the MNLs with sufficiently large apertures and strong focusing power for FSANS experiments. In this study, we evaluate the focusing property of the MNLs for the polarized neutron beam, and performed FSANS experiments using the MNL. The obtained results are discussed.
Suzuki, Junichi
Nihon Kessho Gakkai-Shi, 46(6), p.381 - 389, 2004/12
no abstracts in English
-isopropylacrylamide)-
-poly(ethylene glycol) in waterMotokawa, Ryuhei; Annaka, Masahiko*; Nakahira, Takayuki*; Koizumi, Satoshi
Colloids and Surfaces B; Biointerfaces, 38(3-4), p.213 - 219, 2004/11
no abstracts in English
Oku, Takayuki; Suzuki, Junichi; Sasao, Hajime*; Adachi, Tomohiro*; Shinohara, Takenao*; Ikeda, Kazuaki*; Morishima, Takahiro*; Sakai, Kenji*; Kiyanagi, Yoshiaki*; Furusaka, Michihiro*; et al.
Nuclear Instruments and Methods in Physics Research A, 529(1-3), p.116 - 119, 2004/08
Times Cited Count：21 Percentile：77.78(Instruments & Instrumentation)As a neutron has a magnetic dipole moment, it is accelerated in a magnetic field gradient. Thus, we can control a neutron trajectory free from neutron beam attenuation and scattering using the magnetic field gradient. A sextupole magnetic field functions as a neutron focusing and defocusing lens depending on the neutron spin state. The neutron focusing effect was experimentally verified using a 6-piece permanent sextupole magnet. For the application in practical neutron scattering experiments, a sextupole magnet with a sufficiently large aperture accompanied with strong focusing power is demanded. Recently, a superconducting sextupole magnet, a Halbach-type permanent sextupole magnet and a sextupole pulse electro-magnet have been developed in a project of the development and application of neutron optics. These magnets will be dedicated to practical uses in neutron scattering experiments. In this paper, current status of the development of the magnetic neutron lenses is reported, and their application in the neutron scattering experiments is discussed.
