Synthesis, luminescent and dosimetric properties of Li2B4O7:Cu,Ag,Tm

This work reports the preparation of a new thermoluminescent (TL) material obtained by doping the host salt of lithium borate with copper, silver and thulium ions (Li2B4O7:Cu, Ag, Tm). With the obtained material, sintered dosimeters in form of discs were made and exposed to gamma radiation from a(60)Co source. It was found that these dosimeters show a sensitivity of approximately 40% of that shown by the commercial dosimeter TLD-100 (LiF:Mg,Ti). The thermally stimulated luminescence of the prepared material showed a linear response with dose for gamma radiation in the dose range from 0.001 to 50 Gy. Its luminescent signal remains constant during 24 h after irradiation, exhibiting a better behaviour than the commercial dosimeter TLD-800 (Li2B4O7:Mn) which decreases up to 60% of its original signal in the same period. The lower detection limit was determined to be equal to 0.1 mGy and TL measurements showed repeatability within 2.5%. The kinetic parameters were determined using several methods. The variable heating rate method showed the lowest energy valueEof the main peak (peak 1). Initial rise and peak shape methods showed intermediate values whereas the deconvolution method showed the highest energy valueE, using heating rates of 1, 2, 6 and 10 K/s. Results obtained from the morphology, crystallography, Raman spectroscopy and photoluminescence are also reported. These results suggest that this new thermoluminescent detector could be a promising material to use in clinical dosimetry applications.