Determination of the kinetic parameters of the thermoluminescent glow curve of 1% cerium-doped alumina matrices (Al₂O₃:Ce)

In the present work, the kinetic parameters of Tl glow curves of alumina matrices doped with 1% Cerium (Al₂O₃:Ce) are reported. Four 1% cerium-doped alumina pellets were manufactured using the wet impregnation method, with a mass of 30 mg, a diameter of 5 mm and a thickness of 1 mm. The cerium-doped alumina matrices were irradiated in air at room temperature, at doses of 3, 5, 7 and 10 Gy using a 6 MeV linear accelerator (Linac). The Tl reading was recorded on a Harshaw TLD 4500 at 50 to 400° C at a heating rate of 5° C/s. The alumina matrices doped with 1% Ce showed a complex glow curve whose main peak is around 173° C (446 K). Kinetic analysis of the main peak was performed using the initial rise, full brightness peak, and curve fitting methods of Kitis et al. The kinetic order (b) of the main peak is around 1.24, which shows that recombination processes take precedence over re trapping, and the activation energy is around 1.24 eV. Deconvolution of the glow curve using the 4-parameter logistic asymmetric function shows that the curve is constituted by five brightness peaks, around 396 K, 446 K (main peak), 486, 559 and 628 K. In general, throughout the glow curve, recombination processes take precedence over re trapping as a mechanism for deactivating energy traps. (author)