Development of 0.5 mm gauge size radial collimators for high-pressure neutron diffraction experiments at PLANET in J-PARC

Hattori, Takanori; Suzuki, Koji*; Miyo, Tatsuya*; Ito, Takayoshi*; Machida, Shinichi*

Nuclear Instruments and Methods in Physics Research A, 1059, p.168956_1 - 168956_9, 2024/02

https://doi.org/10.1016/j.nima.2023.168956

Radial collimators (RC) with a 0.5 mm gauge size (GS) were specially designed for high-pressure neutron diffraction experiments and their performance and efficacy were investigated. The RCs with nominal GS of 0.75 mm, 1.5 mm, and 3.0 mm effectively exhibited GS of 0.50 mm, 1.07 mm, and 2.78 mm, respectively. The transmissions of all three RCs were almost equivalent. The assessment using a P-E press and a DAC revealed that the anvil scattering was considerably minimized and the sample-to-anvil signal ratio reached values of 0.5 and 2.0 for the PE press and DAC, respectively, when using the 0.5 mm-GS RCs. These results indicate that the 0.5mm-GS RCs have been fabricated as intended and exhibit efficacy for the high-pressure-neutron diffraction experiments, specifically those exceeding 30 GPa. Among those ever manufactured for neutron scattering experiments, the RCs display the smallest GS.

Spontaneous topological Hall effect induced by non-coplanar antiferromagnetic order in intercalated van der Waals materials

Takagi, Hirotaka*; Takagi, Rina*; Minami, Susumu*; Nomoto, Takuya*; Oishi, Kazuki*; Suzuki, Michito*; Yanagi, Yuki*; Hirayama, Motoaki*; Khanh, N.*; Karube, Kosuke*; et al.

Nature Physics, 19(7), p.961 - 968, 2023/07

https://doi.org/10.1038/s41567-023-02017-3

Structural analysis of high-energy implanted Ni atoms into Si(100) by X-ray absorption fine structure spectroscopy

Entani, Shiro*; Sato, Shinichiro*; Honda, Mitsunori; Suzuki, Chihiro*; Taguchi, Tomitsugu*; Yamamoto, Shunya*; Oshima, Takeshi*

Radiation Physics and Chemistry, 199, p.110369_1 - 110369_7, 2022/10

https://doi.org/10.1016/j.radphyschem.2022.110369

Ni silicide synthesis by Ni ion beam irradiation into Si attracts attention due to its advantages including the ability of formation of local structures, the controllability of ion beams, the formability of silicide without heat treatment and the high reproducibility of the resulting specimen. In this work, we investigate the local atomic structure of Si implanted with 3.0 MeV Ni ions. Analysis of Ni K-edge fluorescent-yield extended X-ray absorption fine structure reveals that Ni atoms have mixed structure of metallic-like face-centered cubic Ni and NiSi phases at the initial stage of the irradiation and the formation of NiSi promotes significantly with the ion fluence above 10 ions cm. With consideration of the agreement between the ion fluence threshold for the structural transition and the critical Si-amorphization fluence, it is concluded that the amorphization of Si plays an important role in the synthesis of the NiSi phase in Ni-irradiated Si.

Alternation of magnetic anisotropy accompanied by metal-insulator transition in strained ultrathin manganite heterostructures

Kobayashi, Masaki*; Anh, L. D.*; Suzuki, Masahiro*; Kaneta-Takada, Shingo*; Takeda, Yukiharu; Fujimori, Shinichi; Shibata, Goro*; Tanaka, Arata*; Tanaka, Masaaki*; Oya, Shinobu*; et al.

Physical Review Applied (Internet), 15(6), p.064019_1 - 064019_10, 2021/06

https://doi.org/10.1103/PhysRevApplied.15.064019

Development of spin-contrast-variation neutron powder diffractometry for extracting the structure factor of hydrogen atoms

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

AA2020-0724.pdf:2.05MB

https://doi.org/10.1107/S1600576721000303

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.

Development and operation of an electrostatic time-of-flight detector for the Rare RI storage Ring

Nagae, Daisuke*; Abe, Yasushi*; Okada, Shunsuke*; Omika, Shuichiro*; Wakayama, Kiyoshi*; Hosoi, Shun*; Suzuki, Shinji*; Moriguchi, Tetsuro*; Amano, Masamichi*; Kamioka, Daiki*; et al.

Nuclear Instruments and Methods in Physics Research A, 986, p.164713_1 - 164713_7, 2021/01

https://doi.org/10.1016/j.nima.2020.164713

Devil's staircase transition of the electronic structures in CeSb

Kuroda, Kenta*; Arai, Yosuke*; Rezaei, N.*; Kunisada, So*; Sakuragi, Shunsuke*; Alaei, M.*; Kinoshita, Yuto*; Bareille, C.*; Noguchi, Ryo*; Nakayama, Mitsuhiro*; et al.

Nature Communications (Internet), 11, p.2888_1 - 2888_9, 2020/06

https://doi.org/10.1038/s41467-020-16707-6

How different is the core of F from O ?

Tang, T. L.*; Uesaka, Tomohiro*; Kawase, Shoichiro; Beaumel, D.*; Dozono, Masanori*; Fujii, Toshihiko*; Fukuda, Naoki*; Fukunaga, Taku*; Galindo-Uribarri, A.*; Hwang, S. H.*; et al.

Physical Review Letters, 124(21), p.212502_1 - 212502_6, 2020/05

https://doi.org/10.1103/PhysRevLett.124.212502

The structure of a neutron-rich F nucleus is investigated by a quasifree () knockout reaction. The sum of spectroscopic factors of orbital is found to be 1.0 0.3. The result shows that the O core of F nucleus significantly differs from a free O nucleus, and the core consists of 35% O, and 65% excited O. The result shows that the O core of F nucleus significantly differs from a free O nucleus. The result may infer that the addition of the proton considerably changes the neutron structure in F from that in O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

Enhancement of element production by incomplete fusion reaction with weakly bound deuteron

Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.

Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07

https://doi.org/10.1038/s42005-019-0165-1

Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.

Electrochemical Cs removal and crystal formation from Fukushima weathered biotite in molten NaCl-CaCl

Honda, Mitsunori; Goto, Takuya*; Sakanaka, Yoshihide*; Yaita, Tsuyoshi; Suzuki, Shinichi*

AIMS Electronics and Electrical Engineering (Internet), 3(2), p.102 - 110, 2019/03

https://doi.org/10.3934/ElectrEng.2019.2.102

The possibility of removal and controlling crystal formation from weathered biotite (WB) in clay minerals were investigated using molten salt electrochemistry (EC) in molten NaCl-CaCl under an electrochemical reductive reaction. Cyclic Voltammogram (CV) measurements were performed in the range of +0.5 V to -2.2 V. Several peaks were confirmed in the CV spectra. The peak at -1.4 V represents a reduction reaction of Fe in WB, so we conducted an experiment at -1.4 V for 2 h to reduce Iron (Fe). The Cs removal rate after EC treatment was determined by X-ray fluorescence analysis, and almost 100% Cs removal was confirmed. To understand the effect of the reductive reaction, we performed X-ray Adsorption Fine Structure (XAFS) analysis. Before EC treatment, the Fe in WB was present as a mixture of Fe and Fe. After EC treatment, the presence of Fe was confirmed by XAFS analysis. Based on this finding, EC treatment is effective for reducing Fe in WB. This result indicated that FeO formation was suppressed, and the reduction reaction was effective for controlling crystal formation.