Field Emission, A Newly Practical Electron Source

The properties of the field emission electron source are discussed. These include high current density, small size, no heater, instantaneous response, and a highly non-linear current-voltage relationship. Engineering data are then derived including conductance, perveance, beam power, etc. It is shown that the field emission cathode is electrically stable and that it has long life given suitable environments and/or operating conditions which are specified. Microwave, voltage control and measurement, electron optical and other applications are discussed. A 300-megw flash X-ray tube now in production is described The availability of the field emitter as a newly practical electron source is expected to make possible a number of new devices which may more often complement than compete with existing technology.