Thermoluminescence (TL) and electron paramagnetic resonance (EPR) of dumortierite sensitized by heat treatments

The present study presents the effect of heat treatment on TL and EPR of dumortierite. It was found that applying a heat treatment at 1200 degrees C for 1h, followed by slow cooling to room temperature, is optimal for improving its TL sensitivity. The glow curves of the sensitized dumortierite sample show TL emission bands centered at 350, 475, and 580 nm. The kinetic parameters of the TL peaks were obtained using the Tm-Tstop and deconvolution methods. In addition, sensitized dumortierite exhibits a linear response with gamma-radiation dose and low fading in its TL response. Studies using the technique of EPR were carried out to investigate the defect center EPR signals observed after gamma-irradiation. A single defect center with an axially symmetric g -tensor was observed with principal values g & Vert; = 2.0009 and g perpendicular to = 2.0017. The center was attributed to an F+ center and appears to correlate with the TL peak at 200 degrees C.