Defects in powder samples of Eu3+-doped material, which had been prepared via solid-state diffusion, were studied by means of thermoluminescence and fluorescence measurements. The defects were generated by exposing the powder to γ-rays. The effect of radiation defects was studied by comparing the fluorescence spectra of non-irradiated and γ-irradiated samples. The fluorescence output was found to decrease in the presence of defects. Broad and weak characteristic bands at 425nm, due to Eu2+, were observed; together with Eu3+ emission lines at 575, 594 and 616nm. These were due to 5Do → 7Fj transitions, where j was equal to 0, 1 and 2, respectively. Two thermoluminescence peaks were found for doped powder, whereas only a single peak arose from pure samples. The thermoluminescence emission was also greatly enhanced in the case of doped powder, and this increase was attributed to the presence of impurities. It was noted that defect accumulation depended strongly upon the level of γ-ray exposure.

R.B.Pode, S.J.Dhoble: Journal of Physics D, 1998, 31[1], 146-50