Photo-transferred thermoluminescence of shallow traps in β-irradiated BeO ceramics

Photo-transferred thermoluminescence signals from beryllium oxide (BeO) ceramics were measured in the low temperature range of 10-300 K. Samples irradiated at room temperature using a Sr90/Y90 beta source were cooled down to 10 K and trapped charges were photo-transferred at this low temperature using the light from a high power blue LED emitting at ~470 nm (2.6 eV). Thermoluminescence glow curve recorded at 0.2 K/s heating rate exhibited three peaks around 90, 160 and 185 K. The analyses of the TL peaks of the glow curve were accomplished using curve fitting, differential and peak shape methods. Results obtained from these techniques are in good agreement about the presence of three trapping centers in BeO ceramics with activation energies of 0.24, 0.48 and 0.56 eV. Moreover, the analyses indicated that first-order kinetics (slow retrapping) is the dominant mechanism in the luminescence process. Heating rate dependence of the glow curves was also investigated between 0.2 and 0.8 K/s rates.