Comparison of silicon nanoscale gratings to carbon foils for use in space plasma mass spectrometers

Carbon foils are an enabling technology in plasma mass spectrometers. For example, they are used to ionize incident neutrals via charge exchange or to trigger timing signals in time-of-flight telescopes via secondary-electron emission. However, the mass resolution and overall effectiveness of these spectrometers is negatively affected by foil-induced scattering of both the ions’ energy and trajectory. We report on recent developments on self-supported silicon nanoscale gratings, which have been developed at the University of Michigan. If successful, these gratings will function similarly to carbon foils relative to their ionization and secondary electron yield. The gratings will also be able to suppress EUV radiation and thus enable novel types of instrument architectures. The feasibility of using these gratings as an alternative to carbon foils was investigated. We present results of laboratory data of these gratings to characterize their charge-exchange and electron emission characteristics.