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, 1 wt %) 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 0.5 wt %) 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 24 h of storage in darkness and at room temperature or after an annealing at 120 °C for 10 s. 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 (0.5 wt %) 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.