[S-IT20] Deep Earth Sciences

[SIT20-P10] Development of a real-time constraint of the sample thickness under high pressure by the GHz-DAC ultrasonics

*ryoma ishida¹, Akira Yoneda¹, Ryosuke Matsui¹, Tadashi Kondo¹ (1.Department of Earth and Space Science, Osaka Univercity)

Keywords:GHz-DAC ultrasonics, diamond anvil cell, lower mantle, Finite Element Method

The GHz-DAC ultrasonics is an experimental method to measure elasticity of the deep earth constituents. It is superior to other techniques to be able to measure simultaneously P and S wave velocities even on opaque specimens. It measures travel time of ultrasonic waves in a sample squeezed in diamond anvil cell (DAC). Thus it is needed to constrain the sample thickness in a separate procedure. For this purpose, we developed a real-time constraint of the sample thickness by combining (1) the newly devised instrument to measure distance between the rear surfaces of diamond anvils, (2) evaluation method of the load on diamond anvil through length change of disk springs, and (3) finite element method to examine elastic deformation of the diamond anvils. In this presentation, we show the P wave velocities of ferropericlase at 67 GPa by comparing with those reported in the previous studies.