Effects of 60Co gamma-ray irradiation on the optical properties of natural and synthetic quartz from 85 to 300 K

Optical absorption and luminescence measurements have been made between 85 and 300 K on natural and synthetic quartz during and after ⁶⁰Co gamma-ray irradiation. Absorption vs. dose curves can be resolved into the sum of a saturating exponential and a linear component. At 85 K the slope of the linear component is small, while at 300 K the linear term dominates the growth curves. The coloring induced by irradiation at 85 K decreased in a complex manner during anneal at a linear rate to 300 K. During this annealing process multiple-peak thermoluminescent (TL) glow curves were observed and recorded. The TL emission spectra are described accurately by single Gaussian-shaped bands, whereas the gamma-ray induced luminescence is comprised of several poorly resolved bands. All recorded TL glow curves are characterized by a set of four first order glow peaks between 150 and 220 K. The temperature dependence of radioluminescence intensity is described by a classical model in which a temperature-independent radiative transition competes with a thermally activated non-radiative process.