Neutron irradiation effects on the structural properties of KU1, KS-4V and I301 silica glasses

In this paper, we have studied the effects of high neutron fluences (10²¹ and 10²² n/m²) and high γ-ray doses (23.8 MGy) on the structural properties of three different types of silica glasses: two high purity silica with different OH content, KU1 (800 ppm) and KS-4V (≤ 0.2 ppm); and a commercial silica Infrasil 301 (≤ 8 ppm). The experimental results obtained by Raman and Fourier transform infrared (FTIR) spectroscopies have been compared with ab-initio simulations and show that, while the global changes on the structure of the gamma-irradiated silica are not significant, the structural changes due to neutron irradiation result in an increase of the number of strained bonds responsible for the formation of new defects that alter the optical properties of the glasses. (authors)