DUAL MODE ULTRASONIC INTERFEROMETRY IN MULTI-ANVIL HIGH PRESSURE APPARATUS USING SINGLE-CRYSTAL OLIVINE AS THE PRESSURE STANDARD

摘要

Acoustic measurements of compressional (P) and shear (S) wave travel times were performed in a 1000-ton uniaxial split-cylinder apparatus (USCA-1000) of the Kawai-type up to 10GPa at room temperature, using dual mode lithium niobate transducers and ultrasonic interferometry. The cell pressures were calibrated continuously by in-situ measurements of the travel times in a single crystal San-Carlos olivine buffer rod inside the cell assembly. Elastic compressional and shear wave velocities in a dense, fine-grained polycrystalline Al{sub}2O{sub}3 were measured simultaneously to 10 GPa; from these data, the elastic moduli and their pressure derivatives were obtained for the longitudinal modulus {L{sub}0 = 461(3)GPa, (L{sub}0){sup}' = 7.0(1)}, the shear modulus {G{sub}0 = 162(2)GPa, (G{sub}0){sup}' = 1.9(1)} and the bulk modulus {K{sub}0 = 245(3) GPa, (K{sub}0){sup}' = 4.5(1)}.