Luminescence of MgF2-WO3 ceramics synthesized in the flux of 1.5 MeV electron beam

The results of comparative analysis of optical properties of MgF₂ single crystals and MgF₂ ceramics, non-doped and doped with tungsten trioxide obtained in the process of high-speed radiation synthesis in air under a flux of 1.5 МеV electrons, are presented. The synthesized ceramics are found to have a high degree of crystallinity, their elements composition is close to stoichiometric, and the phase composition is a rutile lattice. Using time-resolved spectroscopy, it was shown that the initial defectiveness of as-synthesized ceramics samples is represented by emission centers belonging to WO₃ complexes and radiation defects of F₂- types with spectral-kinetics parameters similar to those in irradiated by ionizing radiation MgF₂ single crystals. The ratio between these types of defects is determined by the temperature and luminescence excitation method and the ratios between dopant and co-dopant (LiOH). In MgF₂ ceramics samples, being exposed to ionizing radiation, two radiative channels of relaxation of electronic excitations were found: T-So (triplet-singlet) emission transition in self-trapped excitons (STE) at 3.2 eV and recombination of F–H Frenkel pairs accompanied with the emission at 4.0 eV. The temperature dependences of these channel efficiency in the range of 5–300 K are similar to those ones observed in MgF₂ single crystals.