Component-resolved bleaching spectra of quartz optically stimulated luminescence: preliminary results and implications for dating

Bleaching spectra of the 'fast' and 'medium' optically stimulated luminescence (OSL) components of quartz are reported. A dependence of photoionization cross-section, sigma, on wavelength was observed for the fast and medium components and a significant difference in their responses to stimulation wavelength was found. The ratio of the fast and medium photoionization cross-sections, sigma(fast)/sigma(medium), varied from 30.6 when stimulated with 590 nm light to 1.4 at 375 nm. At 830 nm the fast and medium photoionization cross-sections were found to be sufficiently different that infrared bleaching at raised temperatures allowed the selective removal of the fast component with negligible depletion of the medium. A method for optically separating the OSL components of quartz is suggested, based on the wavelength dependence of photoionization cross-sections. (C) 2003 Elsevier Ltd. All rights reserved.