Surface Ionization with Cesiated Converters for Space Applications

Neutral particle imaging can be used for remote sensing of magnetospheric plasmas. Due to the low fluxes of neutral particles and the very transient nature of many phenomena in such environments, a highly sensitive detection method is required. Neutral particles in the energy range between 10eV and 1keV have not previously been accessible to a mass, energy and angle analysis. Surface ionization, a well-established laboratory technique, can efficiently convert neutral particles in this energy range into negative ions to be analyzed with mass spectrographs. This article describes surface ionization with low work function surfaces as a method and discusses its applicability in spaceborne instrumentation.