Thermal Annealing Effect on the Thermoluminescence Properties of Commercial High-Pressure High-Temperature Diamond Powders

Diamond applications as thermoluminescence (TL) radiation detectors and dosimeters are extensively studied, especially in synthetic chemical vapor deposition (CVD) and high-pressure high-temperature (HPHT) diamonds. Herein, a comparative study of the thermal annealing (TA) effect on the TL properties of four samples of commercial HPHT microdiamonds (MD) powder with a 10-600 mu m-sized range purchased from PlasmaChem is reported. The TL measurements and irradiations are performed using a RISo TL/OSL reader (beta-radiation, Sr-90/Y-90). The TL glow curve analysis and dose behavior are studied with and without TA. The TL glow curves are composed of mainly two broadbands located around room temperature (RT) at 127 degrees C and 127-400 degrees C. TA at higher temperatures produces a shift of the maximum TL peak toward the higher-temperature side. After TA at 1000 degrees C, the TL repeatability is significantly improved with deviations around 3.4%, showing better TL performance. The TL fading in 24 h immediately after irradiation at RT is observed to be around 49-60% without TA and 18-26% after TA at 1000 degrees C. The present findings demonstrate that TA at 1000 degrees C increases the TL performance of the HPHT MD particles as TL dosimeters suitable for ionizing radiation.