Electron spin resonance measurement of irradiation defects in vitreous silica irradiated with neutrons and ion beams

The electron spin resonance (ESR) measurement of irradiation defects in ion beam irradiated vitreous silica was performed. The spin densities of E′ centers, non-bridging oxygen hole centers (NBOHCs), and peroxy radicals (PORs) were measured as a function of the ion beam intensity, fluence, and post-irradiation isochronal annealing temperature. The results of the ion beam irradiation were compared with those of neutron irradiation, and both results were consistently explained by considering the dpa values of irradiation. Based on the proposed mechanism and mass balance, the concentration of the other defects such as oxygen deficiency centers (ODCs) were evaluated.