Thermally stimulated and photostimulated luminescence from long duration phosphorescent SrAl2O4:Eu, Dy crystals

The traps in long duration phosphorescent SrAl2O4:Eu2+, Dy3+ crystals have been evaluated using thermally stimulated luminescence and photostimulated luminescence (PSL) techniques. Afterglow phosphorescence is not observed at temperatures lower than 150 K. Traps with depths of Et,TSL = 0.0024, 0.46, and 0.49 eV are detected by thermally stimulated luminescence techniques. Photostimulated luminescence evaluations reveal that trapped carriers can be released optically using an infrared laser with Et,PSL = 0.55 eV. The trap at Et,PSL = 0.55 eV detected by the PSL may be correlated with the shallow trap levels at Et,TSL = 0.0024 eV.