Luminescence studies on electron and structural states in dielectrics under irradiation

Spectra of radiation-induced luminescence (RIL) and photoluminescence (PL) of Al2O3 and BeAl2O4:Cr3+ single crystals and BN ceramics have been obtained. In Al2O3 under 8 MeV proton irradiation, the recharging of defects causing RIL has been shown to occur in the track vicinity of 10(-6) cm size. After neutron irradiation, an essentially non-equilibrium distribution of Cr3+ impurities over structurally distinguishable sites in the crystal lattice of BeAl2O4 was registered by PL spectroscopy. An effective temperature characterising this distribution under neutron irradiation exceeds the melting point of the material. The RIL and PL of BN were caused by colour centres on grain boundaries. Radiation-induced structural transformations in BN ceramics under neutron and 26.7 MeV Ne ion irradiation principally occur on the grain boundaries but not in the bulk of grains.