Simulations of the predose technique for retrospective dosimetry and authenticity testing

The predose technique of thermoluminescence (TL) for quartz has been used extensively for retrospective dosimetry and archaeological authenticity testing. In this paper, we use a previously published comprehensive kinetic model for quartz, to simulate the complete sequence of experimental steps taken during the additive dose and the multiple activation versions of the predose technique. The simulation results show how both versions of the predose technique can reproduce the paleodose received by the sample with an accuracy of 1–5% in the low dose region of 0–2 Gy. For doses greater than ∼2Gy the non-linear dose dependence of the sensitivity of the “110∘C” TL peak causes significant inaccuracies in the technique. The solution of the kinetic differential equations elucidates several electron and hole processes taking place during the experimental predose procedure; these processes include the thermal transfer of holes from the Zimmerman hole reservoirs to the luminescence center, the radiation quenching of the TL sensitivity and the radiation-enhanced sensitivity of quartz samples. Specific numerical examples are given for samples exhibiting the thermal activation characteristics of “low-S0S0” and “high-S0S0” values. Quantitative results are presented for the effect of the test dose and of the calibration beta dose ββ on the accuracy of both versions of the predose technique. Results are also presented for the sensitivity of the predose technique to the natural variations of the hole concentrations in the luminescence center. Finally, the results of the predose technique simulations are compared with those from simulating the popular single aliquot SAR/OSL technique based on optically stimulated luminescence signals.