Optical phenomena observed in low‐energy ion and electron bombardment of silica surfaces

Optical spectroscopy has been used to characterize the interaction of ionizing radiation with glasses, including ions with energies in the 3–10 keV range, and electrons with energies ranging from 320 to 640 eV. Characteristic line emission spectra of desorbed excited atoms, as well as luminescence spectra from the near‐surface bulk, were observed. A search for possible changes in desorption mechanisms as a function of radiation dose was carried out by observing the time dependence of integrated intensity and spectral linewidth for desorbed silicon and the trace element calcium. Defect formation in the near‐surface bulk was monitored by spectrally resolved, time‐dependent measurements of the bulk luminescence and by electron paramagnetic resonance spectroscopy. These spectroscopic observations are correlated with identifiable differences in the manufacturing processes of several silicas, and thus can be related to one particular kind of surface radiation damage, namely, ion‐ and electron‐induced desorption.