Irradiation damages in lithium oxide

Irradiation defects in lithium oxide, irradiated by oxygen ions with energies of 0.5, 0.75, 1.25 and 100 MeV, were studied by an optical absorption technique. In the optical absorption spectra, a dominant absorption band at about 310 nm in wave length and weak bands at about 375 and 570 nm were observed. The 310 nm band corresponds to F+-centers, and the 375 and 570 nm bands may be due to F aggregate centers. The intensity of the 310 nm band increased with the incident ion energy as well as the fluence. From the considerably large dependence of the intensity on the incident ion energy, the irradiation defect production due to the electron excitation process was conjectured to occur during the oxygen-ion irradiation. Isochronal and isothermal annealing experiments were carried out and the activation energy for recovery of the F+-centers was the same as that for lithium oxide irradiated with thermal neutrons. (orig.)