Photoionization of radiation-induced traps in quartz and alkali feldspars

For the optimization of luminescence dating and dosimetry techniques on the basis of the optically stimulated luminescence, the stimulation spectra of quartz and alkali feldspars were measured in the spectral region of 250-11 00 nm using optically stimulated afterglow. Optically stimulated luminescen ce in all studied spectral regions is induced by the same kind of deep trap s, that produce thermoluminescence in the regions of palaeodosimetric peaks for both minerals. The mechanism for photoionization of deep traps was pro posed as being due to delocalization of the excited state of the correspond ing lattice defects. The excited state overlaps the zone states; i.e, is si tuated in the conduction band. Because of the high quantum yield of deep el ectron trap ionization in the UV spectral region, the present aim was to st udy the possibility of using UV-stimulation for palaeodose reconstruction. (C) 2000 Elsevier Science Ltd. All rights reserved.