Effect of particle size on the thermoluminescence dosimetric properties of household salt

This work investigates the effect of particle size on the thermoluminescence (TL) response of household salt that is classified into five size fractions between 63 and 250 μm. Irradiation induced two main TL peaks at 110 and 240 °C for each particle size fraction. In addition to these peaks, two additional glow peaks were observed at 80 and 300 °C for particles with small size (<90 μm). The complexity of the glow curve pattern increased with decreasing particle size (<125 μm). The intensity of the main dosimetric TL peak at 240 °C increased with increasing particle size. The maximum beta radiation sensitivity of the salt samples was obtained for the particle sizes of 125-180 and 180-250 μm. For different particle sizes, the stability of the dosimetric TL peaks at room temperature was studied over a storage period of 30 days. No systematic difference in the minimum detectable dose values observed for each grain size fraction and it was found to be 0.4 Gy for each grain size fraction. The kinetic parameters of the dosimetric TL peak were determined for different particle sizes using the initial rise and variable heating rate methods. Moreover, the variations in the glow peaks depending on the heating rate were also analyzed. While an expected behavior of low temperature TL at 110 °C was observed, an interesting heating rate behavior (anti-quenching) of the high temperature dosimetric TL peak at 240 °C was observed.