Photoluminescence Comparison of γ-irradiated DyDoped CaWO4 Phosphors

Abstract

Photoluminescenc properties of gamma-irradiated Dy activated CaWO₄ system have been studied. CaWO₄: Dy samples having different concentration of Dy were prepared by solid state diffusion method. Dydoped CaWO4 phosphor has been prepared by solid state diffusion technique and the formation of compound was confirmed by taking XRD pattern. Photoluminescence (PL) emission spectrum of the CaWO4: Dy shows that Dy enters in both Dy²⁺ and Dy³⁺ ionic states in to the lattice. Samples were irradiated with gamma rays using ⁶⁰Co source. Mechanoluminescence (ML) and thermo luminescence (TL) of gamma irradiated CaWO4: Dy (0.1mol%) phosphors have been studied. A single peak has been observed in ML intensity versus time curve. However, two distinct peaks were observed in ML glow curves of the phosphors irradiated with higher gamma doses. Similarly, in TL glow curve a single peak around 120 °C was observed for the samples exposed to gamma dose 250 Gy. Shoulder appears in the TL glow curve if sample irradiated with higher values of gamma dose.