Investigations of the dose-dependent anomalous fading rate of feldspar from sediments

Abstract

Anomalous fading characteristics of feldspar from sediments are investigated using both modelling and experimental data. Based on the theory of tunnelling from electron traps to randomly distributed recombination centres proposed by Huntley (2006 J. Phys.: Condens. Matter. 18 1359-65), the following aspects are modelled: the tunnelling-related decay of the luminescence signal from laboratory-irradiated and naturally irradiated samples, the effects of anomalous fading on the shape of dose response curve (DRC) under natural irradiation, the probability distribution of trap-to-centre distance for laboratory-irradiated and naturally irradiated samples and the dependence of anomalous fading on natural doses and their relationship to the density of recombination centres. The modelling results were tested by measuring the anomalous fading rate and DRCs for K-feldspar from laboratory-irradiated samples and naturally irradiated samples with different ages. The experimental data show that the fading rates for both laboratory-irradiated samples and naturally irradiated samples are strongly dependent on the size of radiation dose received. © 2008 IOP Publishing Ltd.