Host: The Mineralogical Society of Japan
In high-P/T in situ X-ray observation using Kawai-type apparatus, generated pressure is usually determined from the unit cell volume calculated from d-spacings of diffracted planes of pressure standard materials, such as cubic crystals of Au, Pt, NaCl and MgO.
However, possible deviatoric stress exerting on the standard causes serious error to the calculated pressure. In order to determine the appropriate pressure, it is indispensable to evaluate stress state of the standard material. In hydrostatic condition, strains of d-spacings are uniform over diffraction lines. Therefore, it can be interpreted that difference among strains of d-spacings is caused by deviatoric stress. If elastic constants of standard material are known, we can calculate stress from strain using Hooke's law. In the conference, we would like to discuss a new simple (and fully numerical) method established by the present study to estimate magnitude of deviatoric stress in a Kawai-type apparatus.
