Investigation of OSL and thermally assisted OSL in Al2O3:Mg,Y Phosphor

Abstract

We report the photoluminescence (PL), thermoluminescence (TL), TL kinetics, optically stimulated luminescence (OSL) and thermally assisted OSL (TA-OSL) characterization of Al2O3:Mg,Y phosphor. PL studies result in the broad emission of Mg ion around 370-420 nm when excited by 330 nm wavelength. Its TL glow curve consists of two peaks at 120 and 240 ºC. The TL kinetics parameters such as trap depth (E), frequency factor (s) and the half-life of the trapped electron in the respective traps are determined. The material was found to possess strong thermal quenching in TL mode and thereby investigated for its OSL response to get the better efficiency. In OSL mode, it is found to possess three OSL components having photoionization cross-sections of 1.9×10-17, 2.4×10-18 and 4.8×10-19 cm2 respectively evaluated using CW-OSL and LM-OSL methods. The correlation of the TL peak and OSL active traps has been determined. It is found to give linear dose response up to 10kGy in OSL mode, thereby this material is a potential candidate for its application in high dose dosimetry. The temperature dependence of OSL studies showed that integrated TA-OSL initially decreases up to 50°C, then increases up to 120°C. The increase in TA-OSL at 120 ºC can be attributed to temperature dependence of photoionization cross-section.