Photon transferred TL signals from potassium feldspars and their effects on post-IR IRSL measurements

A recent flourish of studies using post-infrared infrared stimulated luminescence (post-IR IRSL) signals for retrospective dose determinations necessitates the investigation of photon transferred thermoluminescence (PTTL) signals induced by IR stimulation for potassium feldspars (K-feldspars). In this study, we investigated characteristics of PTTL signals and their effects on post-IR IRSL measurements for K-feldspars extracted from two bedrock samples. The temperature corresponding to maximum PTTL intensity (Tpeak) and the highest temperature at which PTTL signals are observed (Tmax) increase with the preheat temperature before IR stimulation, although no further increment of Tpeak is observed when preheat is higher than 320 °C. The interference of the PTTL signal with the post-IR IRSL signal is non-monotonically dependent upon the temperature of the latter. The PTTL signals lead to an underestimation of the thermal stability of multiple-elevated-temperature (MET)-post-IR IRSL290 signals and may contribute to poor dose recovery ratios (DRR) using post-IR IRSL290 signals. The DRR values are substantially improved when the temperatures of preheat and post-IR IR stimulation are elevated to suppress the interference of the PTTL signal. This study highlights the importance of a careful inspection on PTTL signals before measuring the post-IR IRSL signals for K-feldspars.