Optically monitored high-pressure gas loading apparatus for diamond anvil cells

We describe a high-pressure system built to load rare gases (He, At, Ne) in various types of diamond anvil cells, at room temperature. These gases are used as pressure transmitting media to obtain the best hydrostatic compression conditions in high-pressure experiments. Optical windows allow control of the loading process. The loading success rate is close to 100% and the initial pressures in the diamond anvil cell are in between 0.2 and 1 GPa. This system can easily be adapted for loading of various gaseous samples, including gas mixtures, which generally cannot be loaded by cryogenic methods.