Low Temperature Cathodoluminescence in Disordered SiO2

In recent charging studies, a discernible glow was detected emanating from sample surfaces undergoing electron beam bombardment that resulted from a luminescent effect termed cathodoluminescence. This suggests that some of the materials used as optical elements, structural components, and thermal control surfaces in the construction of space-based observatories might luminesce when exposed to sufficiently energetic charged particle fluxes from the space plasma environment. A central focus of our experiments was the temperature dependence of the luminescent behavior. Here, an overview of our experimental results is given, as well as a qualitative model to describe the luminescent behavior. We look at a simple model of band theory and the filling of localized or trapped states and the electron transitions from which the luminescence originates.