Silicone fluid as a high-pressure medium in diamond anvil cells

The usefulness of a silicone oil, Dow Corning 200, as a pressure medium in diamond anvil cells has been investigated. Common indicators of deviatoric stresses on ruby, such as changes in the R-line widths and the R2-R1 peak separation, show that this fluid does not deviate from hydrostaticity up to ∼15 GPa (150 kbar). The behavior of silicone is found to be very similar to the commonly used 4:1 methanol:ethanol mixture, while being much easier to use because of its higher viscosity. This ease of use and excellent performance makes silicone fluid a superior pressure medium.