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Absorption band at 7.6 eV induced by γ-irradiation in silica glasses |
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| Authors: | M. Cannas F. M. Gelardi F. Pullara M. Barbera A. Collura S. Varisco |
| Affiliation: | a Dipartimento di Scienze Fisiche ed Astronomiche, Istituto Nazionale per la Fisica della Materia, University of Palermo, via Archirafi 36, I-90123 Palermo, Italy b Osservatorio Astronomico G.S. Vaiana, piazza del Parlamento 1, I-90134 Palermo Italy c Istututo per le Applicazioni Interdisciplinari della Fisica, CNR, via U. La Malfa 153, I-90146 Palermo, Italy |
| 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. |
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