Thermal stability of infrared stimulated luminescence of sedimentary K-feldspar

The thermal stability of the infrared stimulated luminescence (IRSL) signal measured at 50 degrees C as a function of IR stimulation time was investigated using KF grains extracted from sediments from central China. A dependence of thermal stability of IRSL signal on IR stimulation time and stimulation temperature were observed in pulse annealing studies. Relatively lower thermal stability is given by the initial part of the IRSL measured at 50 degrees C, than the later part of IRSL curve. Based on these observations, the thermal stability of the post-IR IRSL signal stimulated at elevated temperatures (100-200 degrees C) was also investigated. It was found that at least two groups of traps (shallow and deep) are associated with the IRSL and post-IR IRSL signals. The IRSL signal obtained at 50 degrees C is mainly from the shallow traps while the post-IR IRSL obtained at elevated temperatures is mainly from the deep traps. The kinetics parameters obtained using pulse annealing test indicate that the shallow IRSL traps are probably associated with the similar to 300-350 degrees C TL peak and the deep traps are probably associated with the similar to 400 degrees C TL peak. The shallow traps (similar to 350 degrees C TL peak) are associated with those easy-to-fade traps and the deep traps (similar to 400 degrees C TL peak) are associated with hard-to-fade traps. (C) 2010 Elsevier Ltd. All rights reserved.