国際的パルス中性子施設と巨大高圧相単結晶合成技術による地球深部水の研究

2015 Fiscal Year Annual Research Report

• Project/Area Number: 15J03633
• Research Institution: Okayama University
• Principal Investigator: プレジャブ ナランゴー 岡山大学, 自然科学研究科, 特別研究員(DC2)
• Project Period (FY): 2015-04-24 – 2017-03-31
• Keywords: single crystal / neutron diffraction / hydrous ringwoodite / hydrous wadsleyite

Outline of Annual Research Achievements

Syntheses of hydrous ringwoodite single-crystals were completed successfully. I conducted 19 experimental runs by using a scaled-up Kawai type cell. Two independent high quality single-crystals of hydrous ringwoodite were measured at the neutron time-of-flight Laue diffractometer at Oak Ridge National Laboratory, USA. The obtained neutron data were analyzed successfully and the results were presented at the Japanese Society of Neutron Science annual meeting 2015 as a poster presentation. During the syntheses of hydrous ringwoodite, I completed analyses of previously obtained single-crystal neutron data of hydrous wadsleyite. I already started the next project, which is to measure the atomic-scale dynamics of hydrogen by quasielastic neutron scattering for deep-earth hydrous minerals. Phase E samples were synthesized by using the above mentioned cell. Totally 11 experimental runs were carried out. First test quasielastic neutron scattering measurement had been conducted on powder sample of phase E.

Current Status of Research Progress

1: Research has progressed more than it was originally planned.

Reason

Before the submission of DC2 application, I planned to conduct the syntheses of high-quality single crystals of hydrous wadsleyite. I also planned its single-crystal neutron diffraction measurements in the first year. Also, a part of syntheses experiments of hydrous ringwoodite single crystals were planned in the end of the first year and to be continued in the second year with its neutron diffraction measurement. Fortunately, syntheses and neutron diffraction measurement of hydrous wadsleyite were made successfully after the submission of DC2 application. So I started the syntheses of hydrous ringwoodite single crystals work much earlier than originally planned and its neutron diffraction measurements were also successful. Also, the test measurement of quasielastic neutron scattering has been conducted for deep-earth hydrous minerals in the end of the first year.

Strategy for Future Research Activity

For the next year, I will continue the project of atomic-scale dynamics of hydrogen by quasielastic neutron scattering in deep-earth hydrous minerals. For this project, I will conduct more additional syntheses experiments for phase E and measure its quasielastic neutron scattering at different temperatures. Then I will proceed the data analyses. Meanwhile, I will submit the manuscripts for single-crystal neutron diffraction of hydrous wadsleyite and ringwoodite, respectively. Finally, I will focus on writing the Ph.D thesis.

Research Products

• [Int'l Joint Research] Oak Ridge National Laboratory(米国)
  • Country Name: U.S.A.
  • Counterpart Institution: Oak Ridge National Laboratory
• [Presentation] Hydrogen in hydrous wadsleyite analyzed by time-of-flight single crystal neutron diffration (2016)
  • Author(s): Purevjav, N., Okuchi, T., Tomioka, N., Wang, X. P., Hoffmann, C.
  • Organizer: Misasa International Symposium MISASA VI “Frontiers in Earth and Planetary Materials Research: Origin, Evolution and Dynamics”
  • Place of Presentation: Blanc Art Misasa
  • Year and Date: 2016-03-08 – 2016-03-11
  • Int'l Joint Research
• [Presentation] Hydrogen sites in the deep mantle hydrous ringwoodite determined by neutron single-crystal Laue diffraction (2015)
  • Author(s): Purevjav, N., Okuchi, T., Hoffmann, C., Wang, X.P.
  • Organizer: 日本中性子科学会
  • Place of Presentation: 和光市民文化センター
  • Year and Date: 2015-12-10 – 2015-12-12