Identification of ESR centers and their role in the TL of natural salt from Lluta, Peru

Abstract

In this study, the thermoluminescence (TL) properties of natural NaCl from Lluta, Arequipa-Peru was investigated. The number of peaks and the kinetic parameters associated with the TL glow peaks of NaCl sample after gamma-irradiation were analyzed by initial rise and deconvolution method. Defect centers induced in pure salt by gamma irradiation have been studied by electron spin resonance (ESR) with a view to identify the centers associated with the TL process in the salt. Thermal annealing experiments indicate the presence of three defect centers. Center I characterized by the g-value 2.011 is identified as an O− ion and relates with the dominant TL peak at 220 °C. Center II with a g-value of 2.0058 is attributed to a F center and is found to correlate with the 128 °C TL peak. Center III has of g-value 2.014 and is also assigned to an O− ion.