Correlation between isothermal Tl and Irsl in K-Feldspars of various types

Abstract

Feldspars are used as natural dosimeters to date geological and archaeological materials. These minerals are widely used in dosimetric methods of dating using luminescence signals, such as Thermoluminescence (TL), Optically Stimulated Luminescence (OSL) and Infrared Stimulated Luminescence (IRSL). The present work is an effort to compare the Isothermal decay Thermoluminescence signals (ITL) to the IRSL signals from four K-feldspar samples which belong to two different species, namely microcline, and sanidine. The experimental data were fitted by analytical expressions coming from a tunneling recombination model. The results prove that all ITL and IRSL signals can be fitted very accurately with the analytical equations and that only two tunneling components are needed to obtain a high-quality fit. These tunneling components consist of a very fast and intense component, which is followed by an extended slowly decaying component. Significant differences were found between the best-fit parameters of the ITL and IRSL signals, indicating that thermal excitation processes may reach different traps from optical excitation processes in these samples.