The relationship between quartz thermoluminescence, photo-transferred thermoluminescence, and optically stimulated luminescence

The effects of green light stimulation on the thermoluminescence (TL) of a sedimentary quartz from the Kimberley region of Western Australia are reported. The loss of TL at 310 degrees C and the concomitant growth and decay of the photo-transferred TI. (PTTL) at both 110 and 160 degrees C are presented for optical stimulation of up to 200 s in a Riso TL/OSL reader. The optical decay lifetime for the 110 degrees C peak was about 130 s, and we deduce that this decay probably arises from optical stimulation of electrons rather than loss of recombination centres. A linear correlation was found between the loss of TL from the rapidly bleaching peak at 310 degrees C (following a natural (N) + 43 Gy dose) and the integrated optically stimulated luminescence (OSL), for stimulation at 125 degrees C and for stimulation times between 0.1 and 100 s. For another N + 43 Gy sample, the OSL signal decreased by about 20% with increasing preheat temperature from 220 to 280 degrees C, after correction for thermal activation of luminescence centres (monitored by an additional experiment). The TL signal associated with this OSL (i.e. the TL lost as a result of optical stimulation) decreased by about 30% with preheat temperature. For repeated 0.1 s stimulation at 25 degrees C, there was a linear relationship between the OSL, and the PTTL at 110 degrees C obtained after each stimulation. The effects of different doses and stimulation times on this relationship are reported, and the implications for dating protocols using the OSL signal are discussed. (C) 1997 Elsevier Science Ltd.