Pressure distribution in a quasi-hydrostatic pressure medium: A finite element analysis

The highest quality pressures on samples in a diamond anvil cell (DAC) at high pressures are produced using quasi-hydrostatic pressurization media such as helium or hydrogen. In this paper we carry out a finite element analysis of pressure distributions in a DAC using helium and non-hydrostatic argon pressurization media. We find that samples and ruby chips are at substantially higher pressures than the pressurization media, although this is sharply reduced by using helium, which has a low yield strength for the shear modulus. The deviations in pressure of the different samples (and ruby) from the pressurization media differ and depend on their elastic constants. Our observations may account for the distribution of pressures in metallic markers found in a recent calibration of the ruby scale to high pressures.