Lu2O3:Tb,Hf storage phosphor

Lu2O3:Tb,Hf ceramics containing 0.1% of Tb and 0-1.5% of Hf were prepared in reducing atmosphere at 1700 oC and their thermoluminescence properties were systematically studied. For comparison Tb,Ca co-doped specimen was also fabricated and investigated. The Tb,Hf ceramics shows basically a single TL band located around 180 oC as found with heating rate of 15 oC/min. Ceramics singly doped with Tb show complex TL glow curves indicating the presence of traps of very different depths. On the other hand Tb,Ca co-doping is beneficial for the development of shallow traps with the main TL band around 70 oC. Hence, the aliovalent impurities, Ca2+ and Hf4+, strongly influenced the traps structure in Lu2O3:Tb ceramics, each of them in its own specific way. Isothermal decay of Lu2O3:Tb,Hf at 185 oC was recorded and its shape suggest that multiple hole trapping occurs in the Lu2O3:Tb,Hf ceramics. Due to the different traps depths the Lu2O3:Tb,Hf ceramics possess properties typical for storage phosphors, while Lu2O3:Tb,Ca is a persistent luminescent material rather.