date: 2011 October 12 (Wed) 15:30-16:30
room: CPS Conference Room
speaker: Asami Sano (Japan Atomic Energy Agency)
organizer: Minami Yasui
title: Neutron diffraction experiments at high pressure and application to deep earth sciences
abstract: High pressure and high temperature experiments play an important role to understand the earth's deep interior. High pressure beamline PLANET is now under construction at MLF, J-PARC at Tokai, Ibaraki. Potential advantages of neutron diffraction in earth science are its abilities to (1) determine the position of light elements such as hydrogen in the minerals (2) penetrate long depth (3) determine the magnetic structure (4) distinguish isotope such as D and H. I will present a brief overview and current status of PLANET. In addition, results of a neutron diffraction study on wadsleyite, which is a main constituent of the upper part of the mantle transition zone, will be reported as an example.
Wadsleyite, a high pressure polymorph of olivine, is known as a "nominally anhydrous minerals" that can contain up to 3 wt.% of H2O. Even a small amount of hydrogen influences the physical properties of wadsleyite, such as elastic properties and electrical conductivities. To emboss the small amount of hydrogen (deuterium), neutron diffraction experiment on wadsleyite was conducted at D20, ILL. I will present the result of the experiments and discuss the effect of hydrogen on the physical properties.
keywords: High Pressure, Neutron diffraction, wadsleyite, mantle transition zone, J-PARC, PLANET