Potential and limitations of the 210°C TL peak in quartz for retrospective dosimetry

Abstract

Abstract The potential of the 210 °C Thermoluminescence (TL) peak in quartz for accurate dose reconstruction is studied by comparative TL and optically simulated luminescence (OSL) measurements on quartz extracted from bricks from a mill in a contaminated village of the Techa River valley, Southern Urals, Russia. The cumulative doses measured with TL were found to be continuously lower (on average 10–20%) than the ones measured with OSL for the same sample and using the same luminescence reader. From dose recovery tests, laboratory kinetic analysis and available meteorological parameters of the sample site for the past 100 years, it is concluded that the most likely reason for the discrepancy is thermal fading of the 210 °C TL peak. By applying a suitable model, an effective lifetime of the electron trap of the 210 °C TL peak of 200–700 years is estimated for the moderate continental climate at the sample site. It is concluded that for samples in regions of continental climate and directly exposed to sunlight, dose measurements using the 210 °C TL peak should be restricted to the last 50–60 years. Applications to older samples should only be considered if bricks are not directly exposed to sunlight or if the background dose is small compared to the anthropogenic dose, as the latter will have been acquired during shorter times and will thus not have been subjected to significant thermal fading.