Radioluminescence of alumina during proton and heavy ion irradiation

Radioluminescence (RL) of sapphire and polycrystalline alumina (p-Al2O3) under 8 MeV proton (flux 2 x 10(12) proton/cm(2)s), 150 MeV argon (4.3 x 10(8) ion/cm(2)s) and 253 MeV krypton (4.3 x 10(8) ion/cm(2)s) ion irradiation has been measured in the UV and visible ranges. The processes causing the changes of RL of sapphire with a dose differ from those of p-Al2O3. Radiation-induced annealing of oxygen vacancies in p-Al2O3 occurs with decreasing F+-band. Inhomogeneous distribution of traps associated with grain boundaries causes electrical charging of microscopic regions in p-Al2O3 and an increase of F-band of RL. The accumulation of charge carriers at traps increases excitation probability of F-center and results in growth of F+-band of sapphire. A ratio of initial to saturation intensity of the F+-band increases with increasing the linear energy loss of incident particles. (C) 2003 Elsevier Science B.V. All rights reserved.