Initial Plasma Tests of the IPROSEC Cathode Device

摘要

The Ion Proportional Surface Emission Cathode (IProSEC) is a low- brightness cathode technology under development for applications where large areas are available for emission and it is advantageous to avoid the space charge effects often associated with bright or intense sources. Space applications include spacecraft charge control and electrodynamic tethers. Surface Emission Cathodes emit electrons by concentrating an electric field between a p-doped insulating substrate and an adjacent metal cathode element. The substrate potential is held positive of the cathode with gate elements. In plasma, the gate is eliminated due to ambient ion flux which maintains the substrate potential near plasma ground. Prototype devices have been tested using a laboratory plasma source achieving sustained and stable operation over a wide bias voltage for a given ion flux. The principle of operation, ion flux proportionality, and prototype performance is discussed.