X-ray absorption techniques were used to analyze local structures in silica glasses, before and after neutron irradiation in a nuclear reactor. The use of Si K-edge EXAFS revealed that the numbers of O atoms which were coordinated with Si had increased after irradiation. This indicated the occurrence of structural relaxation; such that some of the bonds connecting SiO4 units were broken and that Si atoms were likely to form regular SiO4 tetrahedral bonds. Photoluminescence and optical absorption measurements clearly showed different features for O vacancies in the samples. The B2β-type O-deficient center existed as a principal intrinsic defect in fused-silica glass. Another type of B2α center was formed in synthetic silica glass.

X-Ray Absorption and VUV Spectroscopic Studies of Silica Glasses Irradiated in a Nuclear Reactor. T.Yoshida, T.Tanabe, H.Yoshida, T.Ii: Journal of Electron Spectroscopy and Related Phenomena, 2001, 119[2-3], 221-7