Thermal annealing effect on the thermoluminescence of ZnO:Na

ZnO is a semiconductor material with a band gap of 3.37 eV. It exhibits an excellent resistance to radiation in addition it is inert and stable to environmental conditions, also it is not toxic and is insoluble in water. It is known that their optical properties are modified by doping. Thermoluminescence (Tl) is the thermally stimulated emission of light following the previous absorption of energy from radiation. In this work, we report results concerning the effect of different thermal annealing treatments on the thermoluminescence (Tl) features of Na doped ZnO phosphors. The characterized samples were synthesized by a chemical precipitation method and then sintered at 700, 800, 900 °C and 1000 °C for 24, 48 or 72 h. The best reusability into successive irradiation-Tl readout cycles were observed for the samples annealed at 900 °C for 48 h. The characteristic glow curves show three maxima located at ~ 135 °C, ~ 235 °C and ~ 295 °C after exposure to beta particle irradiation in the dose range from 0.5 to 1,024 Gy. The integrated Tl increases by increasing the irradiation dose with no saturation clouds. From the experimental results here reported, we conclude that the synthesized ZnO:Na phosphors are promising to develop new high performance Tl dosimeters and suitable thermal annealing procedures can be used to improve the Tl properties. (author)