Laser heated diamond anvil apparatus at the Photon Factory and SPring-8: Problems and improvements

Two high pressure high temperature in situ x-ray diffraction systems constructed at the Photon Factory and at SPring-8 are described. Both systems consist of a laser heated diamond anvil cell, CO2 or YAG laser heating systems, and an angle dispersive powder x-ray diffraction system with an imaging plate detector. CO2 laser heating has an advantage in that the sample can be heated stably and uniformly due to stable absorption of the sample. Use of type-IIa diamond, however, caused plastic deformation of the anvils. YAG laser heating, compared to CO2 laser heating, can be used to much higher pressures and temperatures, although a good control system is required for stable heating. Various problems encountered during construction are discussed.