Ionic mechanism in the optically stimulated luminescence of quartz

Among the many centres found in crystalline quartz it is well known that Al, substitutional for Si, is always present in different concentrations giving rise at Room Temperature to ionic migration of the associated alkali ions. Many authors evidenced that these alkali ions are involved in trapping and recombination at the basis of Thermally and Optically Stimulated Luminescence, TL and OSL respectively. We have focused our attention on the OSL of quartz that is now widely used in sediment dating, although the trapping-detrapping mechanisms have not yet been clarified. Bulk synthetic crystalline quartz, with known concentrations of Al and alkali ions has been used. There is evidence that an ionic migration is at the basis of the OSL phenomenon, linking OSL emission with the TL peaks known as "110 °C" and "325 °C". This result is also supported by Radioluminescence (RL) measurements performed on swept and unswept quartzes. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA