Luminescence and radiation defects in electron-irradiated Al2O3 and Al2O3:Cr

Luminescence of Al2O3 single crystals doped with Cr3+ (∼500 ppm) (ruby), non-irradiated and irradiated by 50-MeV electrons, has been studied in a wide range of excitation energy (3.75–20 eV) at 9 K and compared with the luminescence of irradiated undoped Al2O3. Irradiation of ruby by 50-Mev electrons (up to fluences of 2 × 1017 e/cm2) does not lead to any significant changes of Cr3+ related luminescence. The comparison of absorption spectra and the excitation spectra of different emissions has shown that the presence of Cr3+ ions strongly reduces the creation of F centers in Al2O3:Cr by 50-MeV electrons.