Prof. Yasuo Ohishi [Japan Synchrotron Radiation Research Institute, SPring-8]
Title: Current Status of High-Pressure X-ray Diffraction Beamline BL10XU/SPring-8 -Structural Analysis for Hydrogen and Hydrogen Compounds
Time: 9:00 - 10:00 AM, Thursday, October 25, 2018
Place: Conference room C206, HPSTAR (Beijing)
Host: Yang Ding
Polycom: 02120001
Abstract:
The high-pressure x-ray diffraction beamline BL10XU of the third-generation 8 GeV synchrotron facility SPring-8, we are committing to the upgraded of the instrument capabilities on achieving combined (sometime simultaneous) measurements with accurate x-ray diffraction analysis over the entire pressure and temperature range, using both synchrotron radiation x-ray and non-synchrotron methods that provide complementary information of material properties.
In order to enhance structural studies of hydrogen and hydrogen compounds under high-pressure, the essential equipment and key techniques have been originally developed at SPring-8 and integrated for our purpose: the intense high-energy x-ray microbeam by stacked compound x-ray refractive lens optics, the simultaneous measurement system of x-ray diffraction, electric resistance, and Raman scattering spectroscopy under high-pressure/low-temperature condition, and the double-sided laser-heating system using two fiber-lasers.
We would demonstrate that, for H2S case [1], the decomposition and reconstruction from H2S to S element and new high-Tc superconductor H3S had been found by combination of local structural analysis using an x-ray microbeam and electric resistance measurement. We were aware that the laser heating methods with in-situ observation by x-ray diffraction and Raman spectroscopy, was very effective for studying the hydrogenation of metals under high pressure [2]. Utilization of similar advanced technology was also applied to research on metallization of hydrogen by laser heating method [3].
References
[1]. M. Einaga, M. Sakata, T. Ishikawa, K. Shimizu, M. I. Eremets, A. P. Drozdov, I. A. Troyan, N, Hirao, and Y. Ohishi, Nat. Phys., 12, 835-839 (2016)
[2]. T. Matsuoka, K. Kuno, K. Ohta, M. Sakata, Y. Nakamoto, N. Hirao, Y. Ohishi, K. Shimizu, T. Kume, and S. Sasaki, J. Raman Spectrosc. 48, 1222 (2017).
[3]. K. Ohta, K. Ichimaru, M. Einaga, S. Kawaguchi, K. Shimizu, T. Matsuoka, N. Hirao, and Y. Ohishi, Scientific Reports, Volume 5 (2015)
Biography of the Speaker:
• Education
1980 – 1984 Faculty of Engineering Science, Osaka University
Awarded the bachelor’s degree
1984 – 1986 Faculty of Engineering Science, Osaka University
Awarded the master’s degree
1986 – 1989 Faculty of Engineering Science, Osaka University
(1986 – 1988) Guest Student in Photon Factory in KEK
1991 Awarded the PhD degree in Technology, Tsukuba University
• Professional Career:
Researcher, Sumitomo Chemical Industry Co. ltd (1989)
Scientist, Japan Synchrotron Radiation Research Institute (1997)
Senior Scientist, Japan Synchrotron Radiation Research Institute (1999)
Team Leader of High-Pressure Research Team, Research & Utilization Division, JASRI (2005)
Invited professor, Osaka University (2010)
Group Leader of Diffraction & Scattering I Group, Research & Utilization Division, JASRI (2015)
• Major research fields:
1984~ Study of structural phase transitions of materials under high-pressure
1986~ High-pressure crystallography and synchrotron radiation x-ray optics
1989~ Structure analysis of materials by using XRD, synchrotron radiation x-rays and neutron scattering
1997~ High-pressure crystallography and instrumentation of high-pressure XRD beamline
• Achievements and highlights of past research activities
Y. Ohishi has been a beamline scientist of BL10XU of SPring-8, which is one of the exclusive high-pressure x-ray diffraction beamlines of the high-energy third generation synchrotron radiation facilities placed at triple-pole (Japan, USA and EU) of the world. Y. Ohishi had taken part in the construction of BL10XU from very early stage (1997~), and had established the beamline and its high-pressure facilities of SPring-8. And also, he had been a leader of the team of materials science under extreme conditions of JASRI from 2005. Y. Ohishi had studied high-pressure materials physics about successive structural phase transition of solid halogens and synchrotron radiation hard x-ray optics in Osaka university and Photon Factory synchrotron radiation facility of KEK. After his graduate course, he had been in charge for materials’ structural investigations in the analytical division of Sumitomo Chemical Industry Co., ltd. by using x-ray technique including synchrotron x-ray diffraction, x-ray absorption, x-ray/neutron small angle scattering. Standing on these various backgrounds, he has been able to reflect his experiences to the designs, upgrades and operations/managements of BL10XU’s facility.
His most important contribution to BL10XU, was an installation of x-ray focusing optics by using newly developed compound x-ray refractive lens in order to obtain x-ray diffraction signals from very small sample under very high-pressure. After this improvement for optics of BL10XU, x-ray diffraction studies of high-pressure materials science under the extreme high-pressure condition had been driven rapidly forward. And also, by the combination with the lase-heating diamond anvil cell system co-developed with K. Hirose of Tokyo Institute of Technology, in-situ x-ray diffraction experiments of minerals under the high-pressure/temperature condition corresponding to the lower mantle and the core of the Earth had been established. In this decade, about 300 papers, including very important results such as 10 papers in Nature or Science, have been published from BL10XU. He has been continuously developing the sub-micron x-ray beam optics for ultra high-pressure and/or pin-point x-ray diffraction experiment. Such advances and upgrades of BL10XU will made it possible to clear the materials and their phase relations of the Earth’s core in the nearest future.