Thermoluminescence characteristics of gamma-irradiated Gd:Mg doped silica glass

This study explores the characteristics of thermoluminescence (TL) yield of silica glass doped with Gd2O3 and MgO for dosimetry via sol-gel route, with varying concentrations of rare earth metal oxides, ranging from 0.1 to 0.8 mol%. Gamma irradiation was delivered using 1.25 MeV Co-60, with entrance doses of 2-10 Gy. The characterization of Gd:Mg-doped SiO2 included assessing TL dose response, sensitivity, linearity index, glow curve, and fading. It has been found that 0.2 mol% Gd:Mg-doped SiO2 shows promising TL dosimetric properties due to its high linearity, high sensitivity, and low thermal fading. In addition, it demonstrated exceptional dosimetric response across the entire dose range studied, with a coefficient of determination R-2 exceeding 91%. A computerized glow curve deconvolution method was conducted to determine the kinetic parameters by using Glowfit software. The glow curves include five peaks associated with activation energies and frequency factors with values 0.88-2.42 eV and 5.58 x 10(6)-7.22 x 10(26) 26 s(-1), respectively. The 0.2 mol% Gd:Mg-doped SiO2 demonstrates minimal fading effects, retaining a significant portion of the TL signal with similar to 33% of the initial signal lost over 28 days post-irradiation. The results indicate that the Gd:Mg-doped SiO2 offers a promising performance as a low-cost passive radiation dosimeters.