Technique for Obtaining True Hydrostatic Pressures to 60 kbar

A sample is enclosed in a liquid-containing steel capsule 3.81 cm in length and 1.27 cm in diameter, which in turn is placed in the pyrophyllite cube normally used as the sample chamber of a 2000-ton hexahedral press. When pressure is applied in the normal manner, it is transmitted to the enclosed sample by a 1:1 mixture of isopentane and pentane. Successful measurements utilizing six electrical leads into the sample region have been made. A manganin gauge to 60 kbar is demonstrated and used to study previously unobserved time-dependent pressure variations attributed to the pyrophyllite flow in the solid-media apparatus.