Extending the pressure and temperature limits of hydrothermal diamond anvil cells

A modified hydrothermal diamond anvil cell (HDAC) has been developed. The cell is designed primarily for use with anvils incorporating internal heaters, but also solves several technical problems limiting the pressures and temperatures that can be reached with conventional HDACs. The essential features of the cell are (i) the pressurizing mechanics ensure strictly parallel alignment and preclude accidental collision of the anvils, (ii) the mechanical anvil holders provide both robust fixation of the anvils without any glue and reliable electrical contacts with the anvil facets, (iii) the diamond anvils can be heated while the anvil backing plates and the holders remain comparatively cool, (iv) stable hydrothermal working conditions to at least 4.5 GPa and 1000 °C can be achieved during the course of sluggish reactions typical of geoscience research thrusts, and (v) large sample volumes are possible, such as diameters of 0.5 mm and heights of 0.1 mm for a 1 mm culet.