6533b822fe1ef96bd127d68c
RESEARCH PRODUCT
Creation of paramagnetic defects by gamma irradiation in amorphous silica
Franco Mario GelardiSimonpietro AgnelloMarco CannasRoberto Boscainosubject
Range (particle radiation)PhotoluminescenceField (physics)Solid-state physicsChemistryAnalytical chemistryAtomic and Molecular Physics and Opticslaw.inventionParamagnetismlawAtomic physicsElectron paramagnetic resonanceHyperfine structureLine (formation)description
An electron spin resonance (ESR) study of the defects induced by γ-rays in various types of natural and synthetic silica is reported. Three main structures were identified: the E′ center and two doublets with field splitting of 7.4 and 11.8 mT, respectively, both centered around the E′ center signal. Another structure partially overlapping the E′ center line was also detected, consisting in three peaks with a maximum field splitting of 1.36 mT. We have investigated the growth kinetics of these centers on increasing the y-ray accumulated dose. In all investigated materials the growth of E′ centers can be interpreted as caused by γ-activated conversion of one or more precursors. The 1.36 mT structure can be considered as a hyperfine structure of the E′ centers generated by the same precursors but interacting with a nuclear spin. The 7.4 mT doublet features a sublinear growth with the γ dose in the whole investigated range (from 0.01 to 1000 Mrad) and a strict correlation with the γ-induced photoluminescence band at 4.4 eV. Finally the 11.8 mT doublet is generated only in natural silica samples and can be related to the γ-induced bleaching of the emission bands at 3.1 and 4.2 eV.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2000-07-01 |