Thermoluminescence and radioluminescence properties of tissue equivalent Cu-doped Li₂B₄O₇ for radiation dosimetry

Thermoluminescence (Tl) and radioluminescence (Rl) properties of lithium tetraborate (Li₂B₄O₇) doped with different concentration of copper (0.25, 0.5, 1 wt %) under gamma and beta irradiation has 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 degrees C and a second low temperature peak centered at 80 degrees C. The low temperature peak disappears completely after 24 hours of storage in darkness and at room temperature or after an annealing at 120 degrees C for 10 seconds. 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 %) shown the higher Rl emission and a stable and repetitive response. Results show that Li₂B₄O₇:Cu has prospects to be used in gamma and beta radiation dosimetry. (Author)