OPTICALLY STIMULATED LUMINESCENCE IN KALAHARI QUARTZ - BLEACHING OF THE 325-DEGREES-C PEAK AS THE SOURCE OF THE LUMINESCENCE

Glow growth curves were obtained from a dune sand quartz from the Kalahari desert for the 10s optically stimulated luminescence (OSL) generated by 550 nm illumination, the rapidly bleaching peak (RBP) at 325 degrees C for a 20 degrees C/s ramp rate, photo transferred TL (PTTL) into the 100 degrees C peak, and the slowly bleaching peak (SBP) at 375 degrees C (with some contribution from the small peak at 280 degrees C) for a 20 degrees C/s ramp rate. These glow growth curves were identical for the OSL and the RBP, to within a multiplicative factor, supporting the idea that the same population of charged traps was being sampled. The glow growth curves for the PTTL and the SBP differed from those for the OSL and RBP and each other. All curves conformed reasonably well to saturating exponentials and the estimated doses derived from all four were in essential agreement.