Dominant role ofE′centers in x-ray-induced, visible luminescence in high-purity amorphous silicas

Detailed measurements of the x-ray-dose dependence of spectrally resolved x-ray-induced luminescence in bulk high-purity $a$-Si${\mathrm{O}}_2$ were performed. The dose dependence of the luminescence intensity is compared to that of the paramagnetic $E_{\gamma }^{\prime }$-center concentration in two types of silicas. Clear experimental evidence is presented that the main features of the 2.6 and 2.75 eV luminescence bands are due to the same radiation-induced defect, and that this defect is related to the $E_{\gamma }^{\prime }$ center.