Absorption band at 7.6 eV induced by γ-irradiation in silica glasses
- Authors: Cannas, M.; Gelardi, F.; Pullara, F.; Barbera, M.; Collura, A.; Varisco, S.
- Publication year: 2001
- Type: Articolo in rivista (Articolo in rivista)
- Key words: Ceramics and Composites; Electronic, Optical and Magnetic Materials
- OA Link: http://hdl.handle.net/10447/214941
Abstract
Optical absorption of defects induced by γ-irradiation in both natural and synthetic silica is experimentally investigated in the vacuum-ultraviolet (UV) range. Our results show that γ-rays, in a dose range of 1000 Mrad, induce an absorption band centered at 7.6 eV, the so-called E band, whose growth kinetics is not related to γ-activated precursors but to defects of the glassy matrix directly induced via the breaking of Si-O bonds occurring under γ-irradiation. Moreover, we observe that γ-rays do not bleach the E band present in some silica samples before irradiation, so ruling out that the associated defects can be precursors of the paramagnetic E′ centers, also induced by γ-irradiation.