Patent ID: 8736170
Filing Date: 2014-05-27
Classification: H01J

Abstract:
1. A cold field emission electron source comprising: an electron emitter, having a sharpened end forming an emitter tip, the axis of the emitter defining a source emission axis; an extractor electrode, located in front of the emitter tip, the extractor electrode having a hole approximately centered on the source emission axis; an emitter enclosure electrode, located behind the emitter tip, the emitter enclosure electrode having a hole approximately centered on the source emission axis, the hole diameter being larger than the diameter of the emitter wire so that the emitter tip extends past the emitter enclosure electrode, the extractor electrode and the emitter enclosure electrode forming a substantially enclosed volume defined by an inner surface of the extractor electrode and an inner surface of the emitter enclosure electrode; and a cleaning filament positioned within the volume for cleaning the inner surfaces of the extractor electrode and the emitter enclosure electrode.