Thermoluminescence and optical studies on γ-ray irradiated KCl:Tb3+ crystals

This paper reports thermoluminescence (TL), optical absorption, photoluminescence (PL), photo-stimulated luminescence (PSL) and TL emission studies on KCl: Tb3+ crystals irradiated at room temperature. The glow curve of gamma irradiated crystals reveals two peaks at 423K, and 513K. Illumination with light of 560nm leads to a drastic change in the TL glow curve. PL of these crystals exhibits characteristic Tb3+ emissions due to transitions from the D-5(3) and D-5(4) levels to various levels of the F-7 septet. On F-bleaching the -irradiated crystals Z(3) centers are observed. The presence of the characteristic emission due to Tb3+ ions in the PSL at the F band confirms the participation of the Tb3+ ions in the recombination process. The defects generated by irradiation were monitored by the optical absorption and the thermally stimulated luminescence. Trap parameters for the TL process are calculated and presented. Emission of the TL glow peaks contains the characteristic emission of Tb3+ in addition to the emission due to the recombination of the F electron with V - type centers.