Convenient optical pressure gauge for multimegabar pressures calibrated to 300 GPa

The accurate measurement of pressure by a straightforward and inexpensive optical procedure has been needed in the multimegabar region since static pressures over 216 GPa, 361 GPa, 420 GPa and 560 GPa were obtained in the diamond anvil cell. Here, a simple optical pressure gauge based on the Raman shift of the diamond at the center of a diamond tip at the diamond-sample interface is calibrated against a primary gauge (Pt isotherm at 300 K from shock data) to 300 GPa, thus enabling researchers who do not have a synchrotron to conveniently measure pressure with an optical scale from 50 to 300 GPa. (C) 2005 American Institute of Physics.