Time-resolved OSL studies on BeO ceramics

Time-Resolved Optically Stimulated Luminescence (TR-OSL) from BeO ceramics was investigated using a blue laser (445 nm) as stimulation light source. It was observed that, at relatively low dose levels (up to similar to 25 Gy) the TR-OSL decay curve can be approximated with a single exponential decay function with a lifetime of similar to 26 gs at room temperature. Beyond 25 Gy a new decay component with a lifetime of a similar to 2 ts was observed in addition to the similar to 26 mu s component. Thermal stability, radiation dose response, optical bleaching, measurement temperature dependence of the components of the TR-OSL signal were investigated in detail. As result of these studies, a new OSL component which becomes unstable after 150 degrees C was observed. OSL decay rate of this component was found to be higher than the one which becomes unstable after 300 degrees C. In order to obtain information about the temperature dependence of the luminescence efficiency, luminescence emission lifetime was determined in the temperature range from 30 to 130 degrees C with 10 degrees C steps. Using the temperature dependence of the lifetime, thermal quenching energy was determined to be around 0.56 eV for the 26 mu s component. For the similar to 2 mu s component an enhancement in the component intensity was observed pointing to a thermally assisted process with activation energy of 0.15 eV. (c) 2013 Elsevier Ltd. All rights reserved.