Radioluminescence properties of rare earths doped SrAl2O4 nanopowders

Nanopowders of SrAl2O4 pure and doped with rare earths were prepared via a proteic sol-gel methodology. The prepared materials presented a single crystalline phase, confirmed by XRD measurements. AFM results indicate that the average particle size is about 53 nm for SrAl2O4 powders. The radioluminescence spectrum of SrAl2O4: Eu2+, Dy3+ is composed by two intense peaks around 520 and 570 nm followed by a weaker emission peaking at 615 nm. It was observed that the intensity of RL emission during irradiation with X-rays decreased as a function of the irradiation time, indicating the build up of radiation damage in the nanopowders. The irradiated samples exhibited a persistent radiation damage that changes the colour of the sample, and also influenced the reduction in the scintillation efficiency. The saturation level of SrAl2O4: Eu2+ is 96%, exhibiting good resistance to radiation damage.