Experimental study on elastic anistropy of mantle minerals

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In this fiscal year, I was concentrated on crystallographic orientation measurement and shaping of micro crystal (~500μm or less) of high pressure phases. I introduced a CCD camera to determine X ray position against the small specimen. This system works well even for other projects. Then, I examined appropriate way to shape small specimen, such as treating a grain in water to prevent the specimen flown away.I am preparing a sphere specimen of hydrous β spinal with 3wt% water. This crystal was synthesized by Dr. Anton in this institute, and the water content was determined by Dr. Shinoda at Osaka City University by using FTIR method. The crystal structure of hydrous β spinal is monoclinic. Thus to avoid numerical analysis difficulty, I am considering to make a sphere for the final shape of the specimen by applying the air-round method frequently used in crystallography. This project will be the first example of resonant ultrasound spectroscopy to measure single crystal elasticity of high pressure phases.Furthermore, we made important progress on data analysis of resonant peaks. With utilizing the specialty of lock-in amplifier detecting signal phase shift against reference input, we tried to peak fitting simultaneously on real and imaginary parts. We confirmed the resolution ability of the new algorithm by examining our own data at around 20-30 MHz successfully. We submitted the result, combined with the hardware progress of high frequency resonant ultrasonic spectroscopy, to Review of Scientific Instruments.