Molecular contamination of an EUV instrument in geosynchronous orbit

摘要

Molecular contamination of ultraviolet (UV) optics has been well characterized at wavelengths longer than 120 nm, and some tests have been done at very short wavelengths (10 nm). Characterization of molecular contamination effects at intermediate wavelengths is scarce. This paper draws a parallel between organic light filters and molecular contaminants, considering the contaminant as an extra organic film on an existing filter. This allows the analyst to use Henke light absorptance analysis to characterize extreme ultraviolet (EUV) light attenuation. This technique shows that peak light attenuation occurs near 73 nm (17 eV), rather than the previously assumed 121.6 nm, due to the preferential ejection of 2s electrons in carbon near 17 eV.