FEM simulation of temperature field in a resistance-heated diamond anvil cell

Abstract

The temperature of the sample in a resistance-heated diamond anvil cell is difficult to be measured directly and usually is calibrated by reading from the thermocouple attached to the diamond bevel. It is unclear how the temperature difference between the diamond bevel and the sample is affected by external factors such as thermal radiation and air convection. We performed a finite-element method simulation of the temperature field in the resistance-heated diamond anvil cell under different external conditions, and our simulations demonstrate that a thermal insulation cover of a low emissivity material and a unique double-layer structure can effectively reduce the temperature difference. Meanwhile, there is a non-negligible difference between the sample temperature at ambient pressure and that at high pressure when the diamond bevel has the same temperature. Some results of simulations have been confirmed by experiments using a designed double-layer cover.