High pressure X-ray diffraction of thorium to 30 GPa

Abstract

The lattice parameter variation of thorium metal was measured up to 30 GPa in a diamond anvil cell with an energy-dispersive X-ray diffraction method. A new experimental set-up containing a conical slit for the diffracted radiation was used. The pressure was determined from the lattice parameter of NaCl using Decker's equation of state. Thorium conserved its f.c.c. structure up to 30 GPa. Fitting the results to a second-order Birch equation yielded a bulk modulus B 0 of 58 GPa and a pressure derivative B' 0 of 4.2.