Dual mode ultrasonic interferometry in multi-anvil high pressure apparatus using single-crystal olivine as the pressure standard

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 Al2O3 were measured simultaneously to 10 GPa; from these data, the elastic moduli and their pressure derivatives were obtained for the longitudinal modulus {L-0 = 461(3) GPa, L'(0) = 7.0(1)}, the shear modulus {G(0) = 162(2) GPa, G'(0) = 1.9(1)} and the bulk modulus {K-0 = 245(3)GPa, K'(0) = 4.5(l)}.