Beta radiation induced luminescence of polycrystalline Cu-doped Li2B4O7

Thermoluminescence (TL) and radioluminescence (RL) properties of polycrystalline lithium tetraborate (Li2B4O7) doped with different concentrations of copper (0.25, 0.5, 1wt %) under beta irradiation have been investigated. The feasibility of using this borate in radiation dosimetry at low doses has been evaluated. Tissue equivalent Li2B4O7 was prepared by solid state reaction using mixing stoichiometric compositions of lithium carbonate (Li2CO3) and boric acid (H3BO3) and a solution of CuCl2 as dopant. The glow curve of the most efficient copper doped borate (Li2B4O7:Cu 0.5wt %) shows a main stable peak centered at 225°C and a second low temperature peak centered at 80°C. The low temperature peak fades completely after 24h of storage in darkness and at room temperature or after an annealing at 120°C for 10s. The main peak of the Li2B4O7:Cu remains constant. The TL response of Li2B4O7:Cu shows good linearity in the analyzed dose range. The stability and repeatability of RL signals of the borate have been studied and the Li2B4O7:Cu (0.5wt %) shows the higher RL emission and a stable and repetitive response. Results show that polycrystalline Li2B4O7:Cu has prospects to be used in beta radiation dosimetry.