Understanding the Reasons for Variations in Luminescence Sensitivity of Natural Quartz Using Spectroscopic and Chemical Studies

Journal article, 2017

Natural quartz from diverse provenances exhibit variations in their luminescence sensitivity (photon flux/mg.Gy) that span over ten orders of magnitude. A range of factors (such as crystallization/recrystallization process, irradiation, thermal and optical history) that modify luminescence sensitivity have been considered to explain such differences in luminescence sensitivity. However, a clearly definable/identifiable reason is still awaited; such as, these large variations in luminescence sensitivity are related to commonly occurring luminescence quenchers/enhancers in natural quartz lattice. Towards this, quartz mineral grains extracts from different provenances and from varied depositional environments were examined spectroscopically using Fourier Transform infra-red spectroscopy (FTIR), optically stimulated luminescence (OSL), photoluminescence (PL), time resolved PL (TRPL) decay, thermoluminescence (TL) and the trace element analysis. The present study exhibited an anti-correlation between OSL sensitivity and water content in quartz (estimated through integrated intensity of normalized FTIR signal in the wave number region 3000-3600 cm(-1)), such that a sensitivity change of over 5 orders of magnitude corresponded to a change in integrated water absorption signal by 5 times, but in opposite direction. PL and TRPL results enabled further insights.