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

The electron spin resonance (ESR) measurement of irradiation defects in neutron-irradiated vitreous silica was performed to study the effects of the OH content, neutron fluence, and post-irradiation isochronal anneal to 873 K. Together with the usual paramagnetic states of E′ centers, non-bridging oxygen hole centers (NBOHCs), and peroxy radicals (PORs), some new states were observed in the ESR spectra. The principal-axis g-values of these states lied in the range g∼2.0–2.2, which were typical of O2− ions in solids. Considering these new defects, the observed effects of the OH content, neutron fluence, and post-irradiation isochronal anneal were discussed to obtain some details of the reaction mechanism of the irradiation defects.