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RESEARCH PRODUCT
ESR and PL centers induced by gamma rays in silica
Marco CannasMaurizio LeoneFranco Mario GelardiRoberto Boscainosubject
Nuclear and High Energy PhysicsMaterials sciencePhotoluminescenceGrowth kineticsAbsorption bandRadiochemistryGamma rayAnalytical chemistryGrowth rateInstrumentationCrystallographic defectRadiation hardeningExcitationdescription
We have studied the point defects created by γ irradiation in various types of commercial silica glasses, including both natural and synthetic samples, with different OH content, in the low dose regime (0.05–100 Mrad). We found that the growth rate of E′ centers depends strongly on the silica type, ranging from 2 × 1015 cm−3 Mrad−1 to 6 × 1017 cm−3 Mrad−1. Samples of natural silica are rather susceptible to γ ray exposure, as E′ concentration saturates (typically 5 × 1017 cm−3) for doses as low as a few Mrads. For both synthetic and natural samples, the radiation hardness is higher in wet than in dry silica. Moreover, we found a strict correlation between the concentration of E′ centers and the γ-induced absorption band at 5.8 eV. Finally, exposure to γ rays generates in all the samples a photoluminescence band at 4.4 eV, whose excitation spectrum has a maximum at 4.95 eV. This band exhibits a sublinear growth kinetics in all the investigated samples.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1996-08-01 |