Thermoluminescent properties of MgO:Sm co-doped with different lanthanides

This work presents results obtained from the synthesis of MgO:Sm co-doped with different lanthanides. The material was synthesized by the solution combustion method. With the obtained powder, dosimeters were manufactured in the pellet form; these were sintered at 1173 K for 2 hours. Before irradiation, the dosimeters were subjected to annealing treatment at 623 K for 30 minutes to eliminate any Tl signal generated during their production. They were allowed to cool down to room temperature and subsequently they were irradiated with ⁶⁰Co gamma radiation. The readouts were taken 2 hours after irradiation using a Harshaw Model 4000 Tl reader. The highest sensitivity was found for MgO:Sm,Tb with 0.4, 0.1 mol % of Sm and Tb, respectively. The experimental glow curve presents the main peak at 469 K and a very small peak at 440 K. Deconvolution analysis shows that these are general order kinetics peaks with activation energies of 1.74 and 1.94 eV respectively. The Tl response of MgO:Sm,Tb as a function of the gamma dose of ⁶⁰Co showed linearity up to 500 Gy. The lower detection limit (LDL) or minimum dose that this new material is capable to detect was found to be 0.12 mGy, with a 1.71% variability coefficient. These results suggest MgO:Sm,Tb is a promising material that might be used in dosimetry applications. (author)