Applicability in dosimetry of thermoluminescent Li2B4O7 doped with Cu or Eu impurities

Thermoluminescence properties of Li2B4O7 polycrystalline powder undoped and doped with Cu or Eu impurities are investigated. Glow curves of beta irradiated samples are recorded and the dependences of their shapes and of the peak intensities on the dopant concentrations are determined. The results obtained for Li2B4O7:Cu show, besides a very good agreement with previously reported data for slightly doped samples, the appearance of extra TL peaks with increasing Cu concentration. In the case of Li2B4O7:Eu, a high temperature thermoluminescence peak caused by the impurity is observed at any dopant concentration. Comparison with data concerning undoped Li2B4O7 allows for identification of the contributions of impurities to the glow curves. As an important dosimetric feature, the linearity of the TL response of all dosemeters is determined: a satisfactory behaviour is found for appreciably doped Li2B4O7:Cu, whereas samples doped with Eu or with low concentrations of Cu exhibit supralinearity and sub-linearity phenomena.