Studying the Thermostimulated Luminescence of the Gd2O2S: Tb and Y2O2S: Tb Ceramics Compounds under the X-Ray Excitation

In this paper, we discuss the results of the luminescence properties of gadolinium and yttrium oxysulphides doped with terbium. These materials are known as effective Xray screen phosphors. Their applications are more accessible in a ceramic form. The emission spectra of the Gd2O2S: Tb and Y2O2S: Tb show lines which are associated with 5D3 - 7 FJ’ and 5D4 - 7 FJ (J’ = 0-6, J = 1-6) transitions in terbium. The decay time of the luminescence of these oxysulphides was found to be 200 µs. We found that new defects in the samples appeared after the ceramic formation in comparison with the initial powders. Energy levels of the defects were estimated using thermostimulated luminescence (TSL) measurements. The determined characteristics (light yield, relative concentrations of traps, transparency, and afterglow) of studying ceramics, depend on the pressure conditions and a thermal treatment. The ceramics light yield, was almost the same as that of the powders, despite of the new defects presence. powders were obtained despite the presence of new defects.