Electron generation and delivery system for contamination sensitive emitters

Contamination may be removed from a field emitter unit during operation of the emitter unit in an environment at a pressure that lies within a range between 10-6 torr and 10-8 torr. At regular predetermined intervals an electron beam from an emitter tip may be deflected away from a path through a beam defining aperture and onto an electron collector. An electron beam current to the electron collector may be determined and the emitter unit may be flash heated if the current to the electron collector is below a threshold. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.