Towards a general kinetic model for optically and thermally stimulated luminescence of quartz

Abstract

An attempt to produce a self-consistent general model of quartz luminescence behaviour (thermally and optically stimulated) is presented. Results from a numerical simulation of the quartz electronic system are described. The processes of choosing and testing the numerical parameters are described in detail and the results of the modelling are compared to a wide range of laboratory measurements of several different natural quartz samples. The model comprises five electron trapping centres and four hole trapping (recombination) centres (empirical evidence for multiple hole trapping centres is described). The model is shown to reproduce, to a high level of accuracy, the empirical data for measurements of dose response, phototransfer efficiency, dose quenching, thermal activation, optical de-sensitisation, optical sensitisation, OSL temperature dependence and power dependence, among others, of the natural sedimentary quartz samples measured. The relationship of TL and OSL sensitivity is also examined and the effects of dose quenching on OSL described. A development of the Zimmerman model for dose quenching and pre-dose sensitisation is suggested and the variation in sensitisation characteristics between samples is examined. It is shown that by varying the concentration of hole trapping centres in the model over a relatively small range, it is possible to produce a similarly wide variation in both dose quenching and subsequent thermal activation characteristics to that observed empirically.