New precise measurement of muonium hyperfine structure interval at J-PARC

Ueno, Yasuhiro*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; Ito, Takashi; Iwasaki, Masahiko*; et al.

Hyperfine Interactions, 238(1), p.14_1 - 14_6, 2017/11

https://doi.org/10.1007/s10751-016-1381-7

Macroscopic Separation of Dense Fluid Phase and Liquid Phase of Phosphorus

Katayama, Yoshinori; Inamura, Yasuhiro*; Mizutani, Takeshi*; Yamakata, Masaaki*; Utsumi, Wataru; Shimomura, Osamu*

Science, 306(5697), p.848 - 851, 2004/10

https://doi.org/10.1126/science.1102735

Structural transformation between two liquid structures of phosphorus that occurred at about 1 GPa and 1000C was investigated by in-situ X-ray radiography. When the low-pressure liquid was compressed, dark and round objects appeared in the radiograph. X-ray diffraction measurements confirmed that these objects were the high-pressure liquid. The drops grew and eventually filled the sample space. Decompressing caused the reverse process. The macroscopic phase separation supported the view that it was a first-order liquid-liquid phase transition. X-ray absorption measurements revealed that the change in density at the transition is about 40 % of the density of the high-pressure liquid.

X-ray diffraction of graphite-diamond transformation using various catalysts under high pressures and high temperatures

Utsumi, Wataru; Okada, Taku; Taniguchi, Takashi*; Funakoshi, Kenichi*; Kikegawa, Takumi*; Hamaya, Nozomu; Shimomura, Osamu

Journal of Physics; Condensed Matter, 16(14), p.S1017 - S1026, 2004/04

https://doi.org/10.1088/0953-8984/16/14/011

The graphite-diamond transformation was investigated using in-situ time-resolved X-ray diffraction experiments with a MgO dissolved aqueous fluid as the diamond forming catalyst under conditions of 6.6-8.8 GPa and 1400-1835C. Experiments were conducted using a 180-ton DIA-type cubic-anvil apparatus installed on the beamline BL14B1 at SPring-8, a third-generation synchrotron radiation facility in Japan. By analyzing the kinetic data using the JMAK rate equation, it was clarified that altering the pressure-temperature conditions drastically changes the nucleation and growth process of diamond.

X-ray observations of the diamond formation process in the C-HO-MgO system

Okada, Taku; Utsumi, Wataru; Shimomura, Osamu

Journal of Physics; Condensed Matter, 14(44), p.11331 - 11335, 2002/11

https://doi.org/10.1088/0953-8984/14/44/477

In order to clarify the mechanism of diamond formation in the Earth's mantle, we studied the diamond formation in the HO-fluid by in situ X-ray observation with the simple C-HO-MgO system. The results suggest that the solubility of MgO component increases greatly as a function of pressure. However, the generation of fluid is not a sufficient condition for diamond formation, because the carbon quantity in fluid is not increased drastically until just before the diamond formation temperature. This is the first report of the kinetics study in fluid using synchrotron radiation.

High-pressure X-ray diffraction of icosahedral Zr-Al-Ni-Cu-Ag quasicrystals

Jiang, J.*; Saksl, K.*; Rasmussen, H.*; Watanuki, Tetsu; Ishimatsu, Naoki; Shimomura, Osamu

Applied Physics Letters, 79(8), p.1112 - 1114, 2001/08

https://doi.org/10.1063/1.1394951

no abstracts in English

Construction of laser-heated diamond anvil cell system for X-ray diffraction study at SPring-8

Watanuki, Tetsu; Shimomura, Osamu; Yagi, Takehiko*; Kondo, Tadashi*; Isshiki, Maiko*

Review of Scientific Instruments, 72(2), p.1289 - 1292, 2001/02

https://doi.org/10.1063/1.1343869

no abstracts in English

X-ray diffraction study on structural change in liquid selenium under high pressure

Katayama, Yoshinori; Mizutani, Takeshi; Utsumi, Wataru; Shimomura, Osamu; Tsuji, Kazuhiko*

Physica Status Solidi (B), 223(2), p.401 - 404, 2001/01

https://doi.org/10.1002/1521-3951(200101)223:2<401::AID-PSSB401>3.0.CO;2-L

no abstracts in English

In situ X-ray diffraction experiments under high pressures and high temperatures at BL14B1 beamline

Utsumi, Wataru; Katayama, Yoshinori; Mizutani, Takeshi; Shimomura, Osamu; Yamakata, Masaaki*; Azuma, Masaki*; Saito, Takashi*

Nihon Kessho Gakkai-Shi, 42(1), p.59 - 67, 2000/02

https://doi.org/10.5940/jcrsj.42.59

no abstracts in English

A New cubic anvil press with radial slit system at the SPring-8

Yamakata, Masaaki*; Mizutani, Takeshi; Utsumi, Wataru; Katayama, Yoshinori; Shimomura, Osamu

Science and Technology of High Pressure (Proceedings of AIRAPT-17), p.1109 - 1112, 2000/00

no abstracts in English

Optical ionization of DX center in AlGaAs:Se by inner-shell excitation

Yoshino, Yoko; Takarabe, Kenichi*; Ishii, Masashi*; Katayama, Yoshinori; Shimomura, Osamu

Physica B; Condensed Matter, 273-274, p.781 - 783, 1999/12

https://doi.org/10.1016/S0921-4526(99)00648-1

DX state is strongly localized. This nature could be investigated by observing relaxation process of localized electrons to emptied inner shells. We have found two different optical ionization process of the DX center in AlGaAs:Se (x=0.33,(cm)) by using synchrotron radiation. They are tentatively assigned to be a direct lift of an inner-shell electron to the conduction band (CB) followed by a capture of an electron at the DX center to the emptied inner shell K-edge and the Auger ionization of one electron of the DX center to the CB followed by a capture of another electron to the emptied inner shell K-edge.