Carbon monoxide production in low energy oxygen ion bombardment of pyrolytic graphite and Kapton surfaces

We report the results of an investigation of the interaction of low energy oxygen ions with pyrolytic graphite and Kapton surfaces. CO molecules emitted from the surface as a result of the ion bombardment were detected by a mass spectrometer. Because the ion‐induced signals were small compared to that arising from the CO background pressure in our vacuum system, the ion beam was modulated and the modulated component of the CO signal measured with a lock‐in amplifier. The quantum yield (CO molecules emitted per incident oxygen ion) for graphite rose from 1.9 at 4.5 eV ion energy to 6.6 at 465 eV. Comparable yields were obtained for Kapton. The large size of our yields suggests contributions to the reaction process from the background O₂ molecules in our vacuum system.