Operation of a low-voltage high-transconductance field emitter array TWT

L-3 Communications continues development and testing of a moderate power helix TWT incorporating a new low-voltage high-transconductance field emitter array cold cathode developed by SRI International. The TWT employs a custom electron gun required to control the high beam space charge density created in the acceleration region between the HV cathode surface and the grounded input TWT helix. A custom FEA mounting header was also developed to correctly position the emitter within the electron gun and to allow for electrical connection to the base and gate. The TWT itself uses periodic permanent magnet focusing employing a single sever and a high power collector. The collector was redesigned to maximize pumping speed and improve overall TWT vacuum. The program goals are 100 mA operation at 100 W and 5 GHz.