The LM-OSL signal properties of zircon: OSL signal resetting and dose dependency

초록

In this techinical report, with a view to developing a zircon OSL dating technique, we investigated the physical properties of OSL signals in zircon using LM-OSL (linearly modulated optically stimulated luminescence) measurements. By applying a general-order kinetic model, the zircon LM-OSL signals could be deconvoluted into four constituent signal components (fast, medium, slow1, and slow2), the photoionization cross sections of which were in the range of 10(-17) cm(2) and 10(-21) cm(2). We then examined the signal resetting efficiency of each LM-OSL component in response to optical stimulation. In this experiment, the fast signal component, which has the largest photoionization cross-section, was observed to decrease linearly and to be fully reset within similar to 6 s of blue-light stimulation. On the other hand, the medium and slow1 signal components exhibited exponential decay, reaching similar to 10% and similar to 20% of their initial count rates, respectively, after 50 s of optical stimulation. The slow2 signal component showed no distinguishable decrease in intensity over 180 s of blue-light exposure. As the absorbed dose increased, the intensities of the fast, medium, and slow1 signal components showed clear dose dependency, which was well described with a single saturating exponential function. The fast signal component reached dose saturation at similar to 170 Gy, whereas both the medium and slow1 signal components became dose-saturated at similar to 350 Gy.

키워드