Neutron optics design of a neutron magnetic microscope using Wolter type I supermirror

Soyama, Kazuhiko; Hayashida, Hirotoshi*; Maruyama, Ryuji; Yamazaki, Dai; Goto, Yoshiki*; Kobayashi, Yuki*; Arakawa, Shohei*; Yamamoto, Yugo*; Suba, Kenta*; Yamamura, Kazuya*

JAEA-Research 2024-006, 15 Pages, 2024/10

JAEA-Research-2024-006.pdf:1.51MB

A neutron optics design has been conducted for a neutron magnetic microscope that utilize a Wolter type I multilayer supermirror for the purpose of magnetic fields imaging in magnetic materials. Ray trace simulation was performed for a magnifying imaging optical system with a magnification rate of 12.5 times. Based on classical model of Lamor precession, depolarization due to magnetic domains was simulated, and the effect of slope errors on the Wolter mirror created by the replica method on the spatial resolution of the microscope was investigated. As a result, reference data about the shape error required to obtain spatial resolution on the order of micrometers was obtained.

Sodium-cooled Fast Reactors

Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.

Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07

https://shop.elsevier.com/books/sodium-cooled-fast-reactors/morishita/978-0-12-824076-2

This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.

Improvement in sputtering rate uniformity over large deposition area of large-scale ion beam sputtering system

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

JPS Conference Proceedings (Internet), 33, p.011092_1 - 011092_6, 2021/03

https://doi.org/10.7566/JPSCP.33.011092

no abstracts in English

Coherent magnetization rotation of a layered system observed by polarized neutron scattering under grazing incidence geometry

Maruyama, Ryuji; Bigault, T.*; Saerbeck, T.*; Honecker, D.*; Soyama, Kazuhiko; Courtois, P.*

Crystals (Internet), 9(8), p.383_1 - 383_13, 2019/08

https://doi.org/10.3390/cryst9080383

The in-plane magnetic structure of a layered system composed of polycrystalline grains smaller than the ferromagnetic exchange length was studied to elucidate the mechanism controlling the magnetic properties considerably different from the bulk using polarized neutron scattering under grazing incidence geometry. The measured result, together with quantitative analysis based on the distorted wave Born approximation, showed that the in-plane length of the area with uniform orientation of moments ranging from 0.5 to 1.1 m is not significantly varied during the process of demagnetization followed by remagnetization. The obtained behavior of moments is in good agreement with the two-dimensional random anisotropy model where coherent magnetization rotation is dominant.

Study of the in-plane magnetic structure of a layered system using polarized neutron scattering under grazing incidence geometry

Maruyama, Ryuji

Shiki, 40, P. 11, 2018/09

http://www.j-neutron.com/pdf/Vol40.pdf#page=11

no abstracts in English

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.

Accessible length scale of the in-plane structure in polarized neutron off-specular and grazing-incidence small-angle scattering measurements

Maruyama, Ryuji; Bigault, T.*; Wildes, A. R.*; Dewhurst, C. D.*; Saerbeck, T.*; Honecker, D.*; Yamazaki, Dai; Soyama, Kazuhiko; Courtois, P.*

Journal of Physics; Conference Series, 862(1), p.012017_1 - 012017_6, 2017/06

https://doi.org/10.1088/1742-6596/862/1/012017

The in-plane magnetic structure of Fe/Si multilayers with a polycrystalline grain size less than the ferromagnetic exchange length was investigated using polarized neutron off-specular scattering and grazing-incidence small-angle scattering measurements. These complementary measurements, each of them covering different length scales, together with the data analysis based on the distorted wave Born approximation, revealed lateral correlation in the fluctuating orientation of the magnetization in the layer on a sub-m length scale. The obtained in-plane magnetic structure is consistent with the random anisotropy model, i.e. competition between the exchange interactions between neighboring spins and the local magnetocrystalline anisotropy.

Development of a compact vertical splitting system for the cold neutron beam at JRR-3

Tamura, Itaru; Maruyama, Ryuji; Yamazaki, Dai; Nakamura, Kiyoshi; Yamamoto, Kazuyoshi; Aizawa, Kazuya; Soyama, Kazuhiko

Journal of Physics; Conference Series, 528, p.012012_1 - 012012_7, 2014/07

https://doi.org/10.1088/1742-6596/528/1/012012

To achieve efficient implementation of usage of neutron beam instruments, the instruments were rearranged at C2 cold neutron beam line at JRR-3 by using a newly developed compact vertical splitting system. The splitting system has two compact multi channel benders. The bender has been developed using Ni/Ti supermirrors coated on both sides of 0.2 mm thickness silicon substrates. The curvature radius of the bender is 938 mm and the length of the bender is 320 mm yielding deflection angles of 20. Supermirrors with m=3 were deposited on both sides of silicon substrate by an ion beam sputtering apparatus in JAEA. Neutron flux at the end of the neutron guide that installed at the bender exit of which the deflection angle is 20 was measured by the gold foil activation method. It was measured 1.58 10 n/cm/s. The present study showed that the supermirrors coated on both sides with high reflectivity are suitable for the compact bender.

Effect of Si interlayers on the magnetic and mechanical properties of Fe/Ge neutron polarizing multilayer mirrors

Maruyama, Ryuji; Yamazaki, Dai; Okayasu, Satoru; Takeda, Masayasu; Zettsu, Nobuyuki*; Nagano, Mikinori*; Yamamura, Kazuya*; Hayashida, Hirotoshi; Soyama, Kazuhiko

Journal of Applied Physics, 111(6), p.063904_1 - 063904_10, 2012/03

https://doi.org/10.1063/1.3694001

no abstracts in English

Analysis of buried heterointerfacial hydrogen in highly lattice-mismatched epitaxy on silicon

Yamazaki, Tatsuya; Asaoka, Hidehito; Taguchi, Tomitsugu; Yamamoto, Shunya; Yamazaki, Dai; Maruyama, Ryuji; Takeda, Masayasu; Shamoto, Shinichi

Thin Solid Films, 520(8), p.3300 - 3303, 2012/02

https://doi.org/10.1016/j.tsf.2011.10.081

We succeeded in realizing the epitaxial growth of a Sr layer on Si(111) with an atomically abrupt heterointerface - in spite of its large lattice mismatch (12%) with Si - by introducing a monoatomic layer of H on Si. In order to identify the buried H, we carried out a combination analysis involving neutron reflectometry and resonant nuclear reaction of H(N,)C analysis. We found different neutron reflectivity profiles resulting from a contrast variation between the H and D atoms at the buried heterointerface. Furthermore, the depth -ray intensity profiles revealed that the H at the heterointerface acts as an effective buffer layer that enables it to manage the highly mismatched epitaxy on Si.