The effect of annealing and beta irradiation on thermoluminescence spectra of α-Al₂O₃:C,Mg

The effect of annealing on thermoluminescence spectra of beta irradiated α-Al₂O₃:C,Mg has been studied. Measurements were made on an un-annealed sample and samples annealed at 600, 700 and 900 °C. A glow curve measured at 1 °C/s from samples irradiated to 1 Gy shows a high intensity peak at 163 °C and six secondary peaks of weaker intensity at 43, 73, 195, 280, 329 and 370 °C. When the samples are annealed at 700 or 900 °C, an additional secondary peak appears at 100 °C. The thermoluminescence spectrum of an un-annealed sample measured at 1 °C/s between 300 and 700 nm shows the main emission band at ~ 410 nm and subsidiary emission bands at ~ 325 and 485 nm. The emission from samples annealed at 700 and 900 °C show similar bands except for a decrease in intensity of the emission at 485 nm. The emission bands at 325, 410 and 485 nm are attributed to F⁺, F and F₂²⁺(2Mg) -centres respectively. The decrease of the emission band at 485 nm is deduced to be due to the destruction of the F₂²⁺(2Mg) centre at 700 °C. The emission bands are unaffected by irradiation dose between 10 and 320 Gy. However, when the sample is annealed at or beyond 700 °C, any effects on the F⁺ and F centres emission can be easier distinguished particularly for doses greater than 10 Gy.