Study of CW-OSL and ML characteristics of Ca₂Al₂SiO₇:Dy3+ phosphor for high dose dosimetry application.

Abstract

Ca₂Al₂SiO₇:Dy3+ phosphor was synthesized by solution combustion method. X-ray diffraction study revealed mixed phases of the phosphor annealed up to 1300 °C. Pure tetragonal phase of Ca₂Al₂SiO₇ was obtained after annealing the synthesized phosphor at 1450 °C. Effect of different doping concentration (0.0 M% to 3.0 M%) and different annealing temperature (400 °C to 1450 °C) on the Continuous Wave Optically Stimulated Luminescence (CW-OSL), and Mechanoluminescence (ML) properties of a gamma irradiated Ca₂Al₂SiO₇:Dy3+ phosphor was studied successfully. The optimum CW-OSL intensity was observed for the Ca₂Al₂SiO₇:Dy3+ (0.6 M%, 1100 °C) phosphor (CASO6D-1100), which showed linear and wide CW-OSL dose response (20 Gy to 5.0 kGy), and good reusability. Moreover, the bleaching time for the complete elimination of traps was found to be only 6 min in order to get the phosphor reused. The traps were observed to get gradually vacated after taking the CW-OSL readouts of the pre-irradiated phosphor several times. The ML studies showed that the maximum ML intensity was observed for the Ca₂Al₂SiO₇:Dy3+ (1.0 M%, 1100 °C) phosphor (CASO10D-1100) and exhibited linear and wide ML dose response (10.0 Gy to 2.0 kGy) with good reusability. Gradual decrease in the ML intensity was observed after carrying out repetitive ML readout cycles. Thus, it is found to be a good candidate for dosimetry applications using CW-OSL and ML techniques.