Radiation induced paramagnetic centres in nuclear glasses by EPR spectroscopy

An electron paramagenetic resonance (EPR) investigation of a series of glasses irradiated at room temperature with beta or X radiation sources has been made in order to predict the long term behavior of glasses used in the nuclear waste disposal. EPR spectra of the irradiated glasses have been measured and treated using computer simulations. Simulation of the g factor and hyperfine interaction distributions have led to the identification of different paramagnetic centers in these irradiated glasses. The following paramagnetic defects were identified: boron oxygen hole center (BOHC), HC1 center, two different hole centers, peroxy radical (Oxy defect), E' centers, and electron trapping processes for iron and zirconium ions: Zr4+ + e(-) --> Zr3+ and Fe3+ + e(-) --> Fe2+. In particular, no paramagnetic defects associated with aluminum ions are detected in these irradiated glasses. (C) 1998 Elsevier Science B.V. All rights reserved.