EPR study of Yb-doped irradiated glasses

Yb³⁺ reduction under β and γ irradiation has been studied in aluminoborosilicate glasses by EPR spectroscopy. From the Yb³⁺ EPR line variation, we demonstrate that more than one Yb³⁺ sites coexist in the pristine Yb-doped glasses. Reduction of Yb³⁺ into Yb²⁺ is observed for all integrated doses and Yb doping contents. For doses higher than 10⁸ Gy, an Yb³⁺ ion environment change occurs, this change is correlated with a stabilization of the reduced Yb²⁺ state. The paramagnetic defect concentration displays a linear variation as a function of the logarithm of the dose. The glass doping with Yb₂O₃ leads to a substantial decrease of the defect concentration as well as a modification in the relative proportion of the defects produced. In particular, Yb doping tends to increase the relative content of Oxy defects.