TL, OSL and PL studies in Al2O3Al2O3:Si,Ti phosphor

Thermoluminescence (TL) and optically stimulated luminescence (OSL) characteristics of Al2O3Al2O3:Si,Ti phosphor have been studied. Its TL and OSL sensitivity is 1/9th and 1/120th respectively, compared to that of Al2O3Al2O3:C commercial phosphor. Its dose vs. OSL response is linear up to 5 Gy, beyond which it shows slight supralinearity up to a dose of 3×103Gy. The main TL peak at about 276 °C shows maximum emission at about 405 nm. Deconvolution of continuous-wave OSL (CW-OSL) decay curve suggests three individual CW-OSL decay components corresponding to photoionization cross-sections of 1.2×10-181.2×10-18, 2.7×10-192.7×10-19, 7.0×10-20cm2. For an absorbed dose of 2×103Gy followed by annealing at 530 °C for 20 min and a test gamma dose of 1 Gy, the radiation-induced sensitization factor for the CW-OSL response was 2.1. This can be explained by filling of deep traps (>530∘C). The photoluminescence (PL) spectrum of Al2O3Al2O3:Si,Ti shows emission at 410 nm for excitation at 240 nm. From PL measurements we could not detect any F and F+F+ center emissions in the Al2O3Al2O3:Si,Ti phosphor which is prepared under highly oxidizing conditions. The emission around 410 nm matches the emission reported in the literature for Ti4+Ti4+ ions in Al2O3Al2O3.