Red luminescence emission from potassium feldspars stimulated by infrared

Abstract

The use of the blue–UV Infrared stimulated luminescence (IRSL) from feldspars in luminescence dating has generally been unsuccessful due to age underestimation related to anomalous fading. The red emission from feldspar may however provide a non-fading alternative. A series of experiments are reported here which investigate IR stimulated (λ = 833 ± 5 nm) red luminescence emission from potassium feldspar. The aim is to demonstrate the potential of red IRSL as an alternative to the widely used UV-blue emission IRSL approaches. Five key factors are optimised to increase the dose-related red IRSL signal, and to decrease the background signal levels. These include photomultiplier tube (PMT) characteristics, detection filter combinations, laser diode intensity, measurement temperature, and substrate related effects. Preliminary measurements are described that illustrate the considerable potential of red IRSL for dating applications, including low sensitivity changes from volcanic potassium feldspars and high dose saturation of red IRSL from sedimentary and volcanic potassium feldspars.