Thermoluminescence studies of ultraviolet and gamma irradiated erbium(III)- and ytterbium(III)-doped gadolinium oxide phosphors

Present paper deals with the thermoluminescence (TL) properties of Gd2O3:Er3+, Yb3+ phosphor synthesized by a conventional solid state reaction method. The TL measurements were performed under UV and gamma irradiations. The structural and morphological analysis of the resulting phosphor was carried out by X-ray diffraction (XRD) study and field emission gun scanning electron microscopic (FEGSEM) technique. The functional group determination of prepared phosphor was carried out by Fourier transform infrared (FTIR) analysis. Elemental analysis was carried out by energy dispersive X-ray analysis. The particle size was determined by transmission electron microscopic (TEM) technique. For UV irradiation UV source providing 254 nm wavelength was used. Whereas Co60 gamma source was used for gamma irradiation. The TL response of Gd2O3:Er3+, Yb3+ phosphor for two different radiations was compared and studied in detail. The process and possible mechanism for TL were investigated and discussed with the help of energy level models. The kinetic parameters such as order of kinetics, activation energy and frequency factors were evaluated by peak shape method and curve fitting technique. Effects of varying concentrations of Er3+ and Yb3+ was also investigated. The TL studies were further investigated by applying computerized glow curve deconvolution (CGCD).