Calibration of the ruby pressure gauge to 800 kbar under quasi‐hydrostatic conditions

An improved calibration curve of the pressure shift of the ruby R 1 emission line was obtained under quasi‐hydrostatic conditions in the diamond‐window, high‐pressure cell to 800 kbar. Argon was the pressure‐transmitting medium. Metallic copper, as a standard, was studied in situ by X ray diffraction. The reference pressure was determined by calibration against known equations of state of the copper sample and by previously obtained data on silver.