Synthesis and thermoluminescence characterization of the doped barium aluminate phosphors

The stuffed tridymite type oxide of BaAl2O4 has been regarded as a long persistent phosphor. Thermoluminescence (TL) glow peaks of a powder sample of undoped and, Sm3+, Tb3+ and Pr3+ doped BaAl2O4 prepared by solid state reaction and combustion methods was investigated. The structure of the compounds was monitored by X-ray diffraction (XRD) and found a single-phase compound with a hexagonal structure. By carrying out a series of TL measurements for the temperature range from room temperature to 400 °C, the effect of beta radiation dose and heating rate of undoped, Sm3+, Tb3+ and Pr3+ doped BaAl2O4 phosphors, and also reproducibility are investigated. Peak shape method was also utilized to assess the trap parameters. The activation energy of the main peak at 128 C of undoped BaAl2O4 was found to be 0.97 eV. TL glow curves obtained from undoped, Pr3+ and Tb3+ doped BaAl2O4 decreases with increasing heating rates varying from 0.5 to 15 C.s-1 in a way matching with thermal quenching. Contrary to expectations, anomalous heating rate dependence is observed on Sm3+ doped BaAl2O4 sample with heating rate. A semi-localized transition model has been used in order to explain this anomalous.