Irradiation effects on the low-temperature thermoluminescence (TSL) of quartz crystals

Abstract

The TSL of synthetic quartz below room temperature (RT) was examined for x- and z-growth zone samples. Preirradiation at 320 K by 10 4, 5 MeV electron pulses reduced very much the TSL peaks in the range 115–230 K and a peak at 70 K. Other TSL peaks below 110 K did not change much, while peaks at 252 and 265 K were enhanced by the electron preirradiation. Room temperature X-preirradiation caused most TSL peaks first to increase, and they started to decrease only after several hours of RT irradiation. New TSL peaks at 136, 161 and 181 K appeared after comparatively short RT irradiations. These peaks and a peak at 172 K could also be excited by cycles of X-irradiation at 20 K followed by annealing at 360 K. On preirradiation at temperatures above 250 K the peaks in x-samples increased while those of the z-samples decreased. The restoration by annealing at various temperatures up to above 800 K of the TSL of samples preirradiated at RT is also described. Almost all TSL peaks in the temperature range 115–230 K were observed to emit at 3.26 eV (380 nm) and their emission involved the relesase of electrons into the conduction band and recombination at one luminescence center. We propose that most of these TSL peaks are emitted when electrons are released from defects of the type [ X i Li + ] 0 , in which X i stands for various unspecified defects in the quartz lattice. Our model seems to account well for the observed effects.