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 ∼25 Gy) the TR-OSL decay curve can be approximated with a single exponential decay function with a lifetime of ∼26 μs at room temperature. Beyond 25 Gy a new decay component with a lifetime of a ∼2 μs was observed in addition to the ∼26 μs 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 °C was observed. OSL decay rate of this component was found to be higher than the one which becomes unstable after 300 °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 °C with 10 °C steps. Using the temperature dependence of the lifetime, thermal quenching energy was determined to be around 0.56 eV for the 26 μs component. For the ∼2 μs component an enhancement in the component intensity was observed pointing to a thermally assisted process with activation energy of 0.15 eV.