APPLICABILITY IN DOSIMETRY OF THERMOLUMINESCENT LI2B4O7 DOPED WITH CUOR EU IMPURITIES

Thermoluminescence properties of Li2B4O7 polycrystalline powder undope d and doped with Cu or Eu impurities are investigated. Glow curves of beta irradiated samples are recorded and the dependences of their shap es and of the peak intensities on the dopant concentrations are determ ined. The results obtained for Li2B4O7:Cu show, besides a very good ag reement 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 wi th data concerning undoped Li2B4O7 allows for identification of the co ntributions of impurities to the glow curves. As an important dosimetr ic feature, the linearity of the TL response of all dosemeters is dete rmined: a satisfactory behaviour is found for appreciably doped Li2B4O 7:Cu, whereas samples doped with Eu or with low concentrations of Cu e xhibit supralinearity and sub-linearity phenomena.