TL dosimetry of natural quartz sensitized by heat-treatment and high dose irradiation

The aim of this paper is to report the sensitization of the TL peak appearing at 270 °C in the glow curve of natural quartz by using the combined effect of heat-treatments and irradiation with high γγ doses. For this, thirty discs with 6×1mm2 were prepared from plates parallell to a rhombohedral crystal face. The specimens were separated into four lots according to its TL read out between 160 and 320 °C. One lot was submitted to γγ doses of 60Co radiation starting at 2 kGy and going up until a cumulative dose of 25 kGy. The other three lots were initially heat-treated at 500, 800 and 1000 °C and then irradiated with a single dose of 25 kGy. The TL response of each lot was determined as a function of test-doses ranging from 0.1 to 30 mGy. As a result, it was observed that heat-treatments themselves did not produce the strong peak at 270 °C that was observed after the administration of high γγ doses. This peak is associated with the optical absorption band appearing at 470 nm which is due to the formation of [AlO4]° acting as electron–hole recombination centers. The formation of the 270 °C peak was preliminary analyzed in relation to aluminum- and oxygen-vacancy-related centers found in crystalline quartz.