The press uses two separate modules which switch in and out on a convenient rail system: a 6-8 type Walker module and a Getting-designed cubic-anvil module.

Walker Module

The Walker module is used for achieving pressures up to 25 GPa. In this device, six anvil "wedges" press on 8 cubes which in turn press on an octahedral press medium. This is a schematic cross-section of the module:



We have calibrated the press using a variety of sample assemblies, using both castable ceramic and semi-sintered ceramic pressure media. One of our workhorse configurations is the 14/8 assembly:

• 14 mm edge length octahedron made of semi-sintered MgO plus 5 wt% Cr₂O₃
• Toshiba grade-F WC cubes with a truncated edge length of 8 mm
• Stepped LaCrO₃ heater
• Pyrophyllite gaskets with a cross section of 2.8 x 4.5 mm

This graph shows the pressure calibration for the 14/8 (ram force vs. the pressure of "fixed" transitions):