Akademik Veri Yönetim Sistemi
Journal of Luminescence, cilt.230, 2021 (SCI-Expanded)
© 2020 Elsevier B.V.Although naturally occurring luminescence materials such as quartz and feldspars are generally used for radiation dosimetry and dating, natural borates may also stand as a promising material for dosimetry and dating. We report thermoluminescence (TL) and optically stimulated luminescence (OSL) of one of the most abundant boron minerals in Turkey namely, ulexite (NaCaB5O6(OH)6·5H2O). An X-ray diffraction (XRD) analysis confirmed that the sample has triclinic crystal structure and contains 40.55% of B, 5.92% of Na2O, 12.3% of CaO. A thermogravimetric analysis indicates two stages of dehydration within 60–160 °C, 160–250 °C and dehydroxylation within 260–580 °C. Analysis of TL glow curves using fractional glow and deconvolution reveal that there are four glow peaks at 154, 211, 273 and 327 °C in the glow curve of ulexite. All the glow peaks follow a non-first order kinetics. The activation energies of the traps are estimated from the fractional glow curves as 0.72, 0.93, 1.16 and 1.28 eV and that evaluated from the deconvolution analysis as 0.76, 0.83, 0.96 and 1.27 eV. The lifetimes of these traps are estimated within 1.55 days–3.6 × 104 years. The radiation dose responses of the TL peaks are supra-linear between 8 Gy and 1024 Gy. OSL decay curve of ulexite consists a fast, a medium and a slow component with recombination lifetimes of (0.63 ± 0.08), (7.51 ± 0.71), (93.49 ± 3.62) s respectively. The fast OSL component obeyed first order, whereas medium and slow components obeyed general order of kinetics. The dose response of the medium and slow OSL components showed a sub-linearity from 64 Gy to 4096 Gy whereas the fast component showed linear response between 8 and 4096 Gy.