Hydrothermal diamond anvil cell for XAFS studies of first-row transition elements in aqueous solution up to supercritical conditions

A hydrothermal diamond anvil cell (HDAC) has been modified by drilling hole s with a laser to within 150 mu m of the anvil face to minimize the loss of X-rays due to absorption and scatter by diamond. This modification enables acquisition of K-edge X-ray absorption fine structure (XAFS) spectra from first-row transition metal ions in aqueous solutions at temperatures rangin g from 25 degrees C to 660 degrees C and pressures up to 800 MPa. These pre ssure-temperature (P-T) conditions are more than sufficient for carrying ou t experimental measurements that can provide data valuable in the interpret ation of fluid inclusions in minerals found in ore-forming hydrothermal sys tems as well as other important lithospheric processes involving water. (C) 2000 Elsevier Science B.V. All rights reserved.