Preliminary study on the thermally stimulated luminescence characterization of UVC and beta irradiated tridymite.

Thermoluminescence (TL) emission of tridymite, a quartz-like mineral, could be used for a variety purposes, including basic research, ceramic technology, traditional/medical industry, and dating. The current study focused on the investigation of the thermal effects on both the luminescence emission and structural properties of natural tridymite. Thermally stimulated luminescence of beta and UVC irradiated samples exhibits complex glow curves indicating simultaneous physical-chemistry processes such as phase transitions, dehydration, dehydroxylation or redox reactions involving intrinsic defects (O vacancies giving rise to F+ and F-type centers, Schottky and Frenkel defects), extrinsic defects (dopants) and structural defects (stacking fault defects, linear and planar defects or dislocations). TL glow curves can be analyzed despite the complexity by assuming that photon emission can be fitted to 1st order kinetics. The structural changes observed using thermal X-ray diffraction up to 200 °C indicate that the Miller indices (204) and (321) have only a reversible behavior in the range of 26-29° 2θ. Tests based on the TL also corroborate such reversibility.