Abstract
Methods of the pressure and temperature measurement in diamond anvil experiments are described. In mega bar region, most reliable method for pressure measurement at present is an in situ x-ray diffraction study using synchrotron radiation. Pressure is calculated from the equation of state of a standard material such as gold and an example of experiment at 216 GPa is described.
In high pressure and high temperature experiment, by measuring the peak position and the line width of the ruby fluorescence line, both pressure and temperature can be determined simultaneously. This method, however, can be used only in the pure hydrostatic environment. Under nonhydrostatic condition, similar method can be used by using two standard material such as ruby and Sm doped YAG. Temperature dependence of the wavelength of Sm: YAG is very small and it is easy to determine the pressure even when the temperature is not known at all.
Temperature of the sample during laser heating can be determined from the emitted spectrum from the sample. When the measurement is made in a proper range of the wavelength, reliable temperature can be obtained even when the pressure dependence of emissivity is unknown.
