Impact of dose and heating rate on thermoluminescence kinetics in aquamarine (Be3Al2(SiO3)6:Fe)

The study of a thermoluminescent (TL) material begins with the response of the material to different doses of radiation and different rates of heating (Bos, 2006a), For this reason, the present work deals with the possible variations of the kinetic parameters for two groups of glow curves of beryl in its variety known as aquamarine. (Be₃Al₂(SiO₃)₆: Fe). The exposure and reading process was performed in a RISO TL/OSL DA-20 reader at room temperature. For the development of this work, the sample was irradiated at different doses (Between 4 and 100 Gy) of β-radiation with a source of ⁹⁰Sr/⁹⁰Y. The glow curve was recorded at a heating rate of 1 °C/s. The results show four experimental glow peaks around the 75, 115, 189 y 302 °C. The glow peak with the highest intensity at about 75 °C is referred to as the "main peak". A second set of glow curves was obtained with a radiation dose β of 1 Gy. These were recorded at different heating rates between 0.5 and 5 °C/s. The glow peaks show a shift towards higher temperature values as the heating rate increases, in agreement with theory. However, a slight decrease in the area of the glow peak is observed, more pronounced in the case of the main peak. The kinetic analysis performed on the glow curves recorded at different doses of beta radiation and heating rates, using different methods of kinetic theory, such as the initial ascent method, full peak glow, curve fitting and the dimensionless fitting method, shows that the trapping parameters (activation energy, frequency factor, and order parameter) are independent of the absorbed dose, in the measured range, and of the heating rate used.