Improved performance of wide bandwidth neutron-spin polarizer due to ferromagnetic interlayer exchange coupling

Maruyama, Ryuji; Yamazaki, Dai; Aoki, Hiroyuki; Akutsu, Kazuhiro*; Hanashima, Takayasu*; Miyata, Noboru*; Soyama, Kazuhiko; Bigault, T.*; Saerbeck, T.*; Courtois, P.*

Journal of Applied Physics, 130(8), p.083904_1 - 083904_10, 2021/08

https://doi.org/10.1063/5.0062072

Development of high-polarization Fe/Ge neutron polarizing supermirror; Possibility of fine-tuning of scattering length density in ion beam sputtering

Maruyama, Ryuji; Yamazaki, Dai; Akutsu, Kazuhiro*; Hanashima, Takayasu*; Miyata, Noboru*; Aoki, Hiroyuki; Takeda, Masayasu; Soyama, Kazuhiko

Nuclear Instruments and Methods in Physics Research A, 888, p.70 - 78, 2018/04

https://doi.org/10.1016/j.nima.2018.01.068

The multilayer structure of Fe/Si and Fe/Ge systems fabricated by ion beam sputtering (IBS) was investigated using X-ray and polarized neutron reflectivity measurements and scanning transmission electron microscopy with energy-dispersive X-ray analysis. The obtained result revealed that the incorporation of sputtering gas particles (Ar) in the Ge layer gives rise to a marked reduction in the neutron scattering length density (SLD) and contributes to the SLD contrast between the Fe and Ge layers almost vanishing for spin-down neutrons. This leads to a possibility of fine-tuning of the SLD for the IBS, which is required to realize a high polarization efficiency of a neutron polarizing supermirror. Fe/Ge polarizing supermirror with fabricated showed a spin-up reflectivity of 0.70 at the critical momentum transfer. The polarization was higher than 0.985 for the range where the correction for the polarization inefficiencies of the beamline works properly.

Current status of a new polarized neutron reflectometer at the intense pulsed neutron source of the Materials and Life Science Experimental Facility (MLF) of J-PARC

Takeda, Masayasu; Yamazaki, Dai; Soyama, Kazuhiko; Maruyama, Ryuji; Hayashida, Hirotoshi; Asaoka, Hidehito; Yamazaki, Tatsuya; Kubota, Masato; Aizawa, Kazuya; Arai, Masatoshi; et al.

Chinese Journal of Physics, 50(2), p.161 - 170, 2012/04

http://psroc.org/cjp/issues.php?vol=50&num=2

Picosecond snapshot of the speckles from ferroelectric BaTiO by means of X-ray lasers

Tai, R.; Namikawa, Kazumichi*; Kishimoto, Maki; Tanaka, Momoko; Sukegawa, Kota*; Hasegawa, Noboru; Kawachi, Tetsuya; Kado, Masataka; Lu, P.; Nagashima, Keisuke; et al.

Physical Review Letters, 89(25), p.257602_1 - 267602_4, 2002/12

https://doi.org/10.1103/PhysRevLett.89.257602

no abstracts in English

Disign and evaluation of core flow distribution in High Temperature Engineering Test Reactor(HTTR)

Maruyama, So; Fujimoto, Nozomu; Kiso, Yoshihiro*; Murakami, Tomoyuki*; Takikawa, Noboru*; ; Sudo, Yukio

JAERI-M 88-154, 147 Pages, 1988/08

JAERI-M-88-154.pdf:2.9MB

no abstracts in English

Development of a new polarized neutron reflectometer at MLF in J-PARC, 4

Takeda, Masayasu; Yamazaki, Dai; Hayashida, Hirotoshi; Kubota, Masato; Maruyama, Ryuji; Soyama, Kazuhiko; Asaoka, Hidehito; Yamazaki, Tatsuya; Yoshida, Noboru*; Sakaguchi, Yoshifumi*; et al.

no journal, , 

no abstracts in English

Progress and prospects of coherent X-ray research using high power lasers in JAEA

Kawachi, Tetsuya; Nishikino, Masaharu; Sasaki, Akira; Ishino, Masahiko; Hasegawa, Noboru; Imazono, Takashi; Pikuz, T.; Faenov, A. Ya.*; Magnitskiy, S.*; Maruyama, Momoko; et al.

no journal, , 

Laser-driven X-ray sources are widely used in probing substances for new material development etc. Besides the laser-driven sources have potentials to downsizing and ultra-short duration, we carry out the coherent X-ray research, i.e., soft X-ray lasers and higher order harmonics generation (HHG) and their applications. In the source study, the first observation of X-ray mirage and HHG from relativistic plasma are presented. In the applications, we show the surface dynamics of fs laser ablation of metal observed by the X-ray interferometer. Finally we mention the prospects for the future: By the financial support from government, we started upgrade of J-KAREN laser toward PW level to realize keV coherent X-ray and high energy particle beams. By use of this high peak power laser and another high average power lasers, we will explore the possibility of ultra-short-duration short-wavelength lasers and open up new applications of high average power coherent X-rays.

Ablation mechanism and some ideas of applications of modified surface structures induced by picosecond soft X-ray laser

Ishino, Masahiko; Hasegawa, Noboru; Nishikino, Masaharu; Maruyama, Momoko; Faenov, A.*; Tamotsu, Satoshi*; Pikuz, T.*; Inogamov, N.*; Skobelev, I.*; Kawachi, Tetsuya; et al.

no journal, , 

Soft X-ray laser pulses having a wavelength of 13.9 nm and a duration of 7 ps have an ability to make various nanometer scale damage structures on material surfaces. Our experimental study confirms the theoretical model of an atomistic simulation, which predicts the splash of molten layers occurring under a low electron temperature less than 1 eV and creating nanometer scale surface modifications. We also propose the probable ideas of applications of surface structures induced by the soft X-ray laser pulses. Catalytic substrates for chemical reactions, nanopillar sheet for culturing biological cells, and geometrical structures beneath the surface will be candidates. When we can control the surface modification process, the soft X-ray laser beam will enable us to fabricate three dimensional nanometer scale structures.

Current status of the chopper spectrometer 4SEASONS at MLF, J-PARC

Kajimoto, Ryoichi; Yokoo, Tetsuya*; Nakamura, Mitsutaka; Nakajima, Kenji; Inamura, Yasuhiro; Takahashi, Nobuaki; Maruyama, Ryuji; Soyama, Kazuhiko; Mizuno, Fumio; Shibata, Kaoru; et al.

no journal, , 

no abstracts in English

4SEASONS; A High-intensity chopper spectrometer for inelastic neutron scattering at J-PARC/MLF

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Yokoo, Tetsuya*; Nakajima, Kenji; Inamura, Yasuhiro; Takahashi, Nobuaki; Maruyama, Ryuji; Soyama, Kazuhiko; Shibata, Kaoru; Suzuya, Kentaro; et al.

no journal, , 

4SEASONS is one of the neutron chopper spectrometers in J-PARC/MLF. It is intended to provide very high counting rate up to 300 meV neutron energy with medium resolution (% at ) to efficiently collect weak inelastic signals from novel spin and lattice dynamics especially in high- superconductors and related materials. To achieve this goal, the spectrometer equips advanced instrumental design such as an elliptic-shaped converging neutron guide coated with high- (-4) supermirror, long-length (2.5 m) He PSDs arranged cylindrically inside the vacuum scattering chamber. Furthermore, the spectrometer is ready for multi-incident-energy measurements by the repetition rate multiplication method with a special Fermi chopper, and polarization analysis with He spin filters. 4SEASONS is now under construction and will be ready to use in December 2008. In this paper, we show the design of 4SEASONS and current status of its construction.