Thermoluminescence characteristics of the main glow peak in α-Al2O3:C exposed to low environmental-like radiation doses

Thermoluminescence of alpha-Al2O3:C irradiated to low doses (0.04-7.20 mGy) similar to those measurable in the environment has been investigated. The glow curve consists of a dominant peak near 200 degrees C and two additional glow peaks of weaker intensity at around 74 and 342 degrees C, respectively for measurements made at 5 degrees C/s. Analysis of the main peak using various methods shows that in this low dose range, the peak follows non-first order kinetics and also that the peak is unitary rather than being a composite of two overlapping peaks as is thought to be the case at comparatively higher dose. Its dose response was observed to be linear and the dependence of the luminescence intensity on heating rate showed that the thermoluminescence is subject to thermal quenching. However, further examination suggests that thermal quenching may be more of an effect with increase in luminescence excitation dose. Various parameters obtained from kinetic analysis including quantitative analysis of thermal quenching are given. (C) 2013 Elsevier B.V. All rights reserved.