BeO optically stimulated luminescence dosimetry using automated research readers

The objective of this work is to develop a methodology for precise optically stimulated luminescence (OSL) dosimetry using BeO chips and an automated research reader (Risø TL/OSL reader, Risø National Laboratory), documenting optimum detector preparation procedures, readout conditions, sensitivity, minimum detectable dose, and precision. We investigated the influence of stimulation wavelengths (green versus blue LEDs), pre-irradiation annealing conditions, reproducibility, sensitivity changes with dose or annealing, and precisions in the dose response curve with a reference irradiation. The results demonstrate that with proper annealing (700 °C/15 min) and the readout procedure described here (blue stimulation, total OSL area as the signal, and a fixed dose to correct for detector sensitivity, among other factors), a precision <1% (experimental standard deviation of the data) can be obtained with BeO. A fast OSL component that decays within 0.5 s was observed, but does not affect the results significantly except in specific conditions (initial intensity as the OSL signal, readout within 10 min following irradiation). Sensitivity changes were observed as a function of both readout time and dose, pointing out the need for annealing to reset the sensitivity. Other practical aspects, such as the cross-irradiation and bleaching in the automated reader, and the sensitivity of the signal to dim room red light were also tested. This work provides the basis and a demonstration of a protocol for new users interested in employing BeO for different dosimetry applications, including in medicine, using automated research OSL readers.