Study of Deep Traps in Alkali Feldspars and Quartz by the Optically Stimulated Afterglow

The stimulation spectra of quartz and alkali feldspars were measured in the spectral region of 250-1100 nm, using optically stimulated afterglow. The effective stimulation in the spectral region 250-400 nm is revealed. It is established that the studied spectral region for both minerals was induced by thermally stable traps, depopulating at the temperatures of the palaeodosemetric thermoluminescence peaks. In the frame of the proposed model for the OSL processes in both minerals the observed simulation spectra are thought to be induced by defects of the same kind, with the ground state in the forbidden band and a set of excited states, some of which are located in the conduction band as quasi-local states. Ultraviolet stimulation can be used in luminescence dating and retrospective dosimetry with advantage to increase the information from the signal, compared with the widely used infrared stimulation.