Pressure generation by a double-stage system using sintered diamond as the last stage anvil

Two versions of a double-stage ‘‘2-2 type’’ apparatus have been made in which 5- or 10-mm-diam sintered diamond anvils with 2.5- or 4-mm-diam tips, respectively, are used in the second stage. The experiments show that these apparatuses are capable of attaining static pressures of over 20 GPa. The calibration curves based on electric resistance transitions in Bi, Pb, ZnS, GaP, and on densification of vitreous silica are shown. The characteristic features of the present type of apparatus are discussed.