TWT Operation with Low-Voltage Field Emitter Array Cathode

The implementation of field emitter arrays as an electron beam source for TWTs has experienced some advancement in the recent past. The development of low-voltage Spindt field emitter arrays however have made possible operation at significantly reduced voltages than those required in the past, potentially improving emitter reliability and lifetime. As such, L-3 Electron Devices, teamed with SRI International, is developing a field emitter array TWT (FEA-TWT) employing these new cathodes in order to evaluate their operation in the TWT vacuum environment, to investigate TWT design specific to use of field emitter arrays, and to quantify several aspects of FEA-TWT performance that will be substantially different than those of conventional thermionic-based TWTs. This paper reports the Spindt-type field emitter arrays, which exhibit greatly reduced operating voltages from those of the previous generation of emitters produced by SRI.