The hydrothermal diamond-anvil cell (HDAC) can be applied to study fluids, solids and particularly aqueous samples in situ at high pressures and temperatures. Although such cells are usually used at P-T conditions of less than 3 GPa and 850 °C, experiments with aqueous fluids to 23 GPa and 1025 °C have been reported in the literature.
Because diamonds are transparent over a large range of the electromagnetic spectrum, samples in the HDAC can in principle be studied using any "photon-in – …