Calibration of the ruby pressure scale to 150 GPa

Abstract

AbstractFor many years the ruby pressure standard has been the so‐called quasi‐hydrostatic scale of Mao, Xu, and Bell published in 1986. The calibration was determined by X‐ray diffraction of metal markers in an argon pressurization medium to 80 GPa, along with simultaneous measurement of the shift of the ruby R lines. We have used data in the literature, as well as our own, mostly for ruby in quasi‐hydrostatic helium, to produce a new ruby scale with calibration data that extends to 150 GPa. The new scale shows that at the highest shifts of the ruby R lines the pressures are substantially higher than on the old scale. To understand small systematic shifts of the pressures as determined from the X‐ray diffraction of metal “markers” used in the calibration, a finite element analysis of quasi‐hydrostatic conditions in a diamond anvil cell has been carried out. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)