Pressure and temperature calibration of FB-belt type apparatus was carried out at pressures between 4 and 6 GPa and temperatures between 1000 and 1500 deg C using pressure and t4emperature condition of diamond formation and CaGeO_3 phase transition. Pressure and temperature points used as standard were minmum condition of diamond formation in the Ni-C system at 5.4 GPa and 1384 deg C and in the Fe-66Ni34-C system at 4.98 GPa and 1216 deg C. the temperature dependence of garnet-perovskite phase transition curve of CaGeO_3, P(GPa) =6.9-0.0008T (deg C), determined by Susaki et al. was also used as standard of the calibration. With increasing temperature the cell pressure increases about 20 percent between 1000 and 1500 deg C due to thermal expansion of NaCl used as pressure transmitting medium and the reaction cell. The amounts of pressure increase estimated both from the diamond formation and from CaGeO_3 phase transition agreed within 0.05 GPa.
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