Phase diagram determination up to 823K in minerals using Diamond Anvil Cell

: The ruby fluorescence technique is widely used for pressure measurement inside the diamond anvil cell. However, at higher temperatures estimation of pressure becomes complex due to the broadening of the fluorescence peaks. There are other fluorescence markers upon which temperature has a lower effect. For example Sm: SrB2O7. Here, we present a high pressure - high temperature calibration of Samarium doped SrB2O7. In order to minimize the error in determining the pressure, Strontium Borate along with Ruby were loaded in diamond anvil cell under hydrostatic conditions and fluorescence measurements were carried out upto temperatures of 823K under pressure. An equation routine is obtained to fit the peaks at various temperatures upto 823K under pressure. Using this data for pressure determination, phase diagram of Lawsonite was studied and the results are discussed.