Spatially Distributed Electron Beam Gun for High Pulse Repetition Rate Operation

We propose herein the exploration and design of a spatially-distributed electron gun capable of generating approximately 1.25 A at a beam voltage of around 20 kV. The actual beam current and voltage is subjected to considerations of the power supply in terms of size and weight. The electron gun will incorporate a focus electrode to effect a high-repetition rate operation and to reduce stresses on the power supply with a reduced voltage swing. An evaluation of various potential beam-wave circuit interaction circuits will also be performed to ensure efficient RF performance and to avoid potential spurious oscillations once the interaction circuit is integrated with the gun and magnet into a fully functional amplifier upon transition. The resulting electron beam will be matched with a light weight magnet system, which depending on the outcome of the evaluation can potentially be either a periodic permanent magnet (PPM) system or a “circuit only” solenoidal permanent magnet system. The overall goal is to maximize the RF power to weight ratio of future amplifiers. In the Phase-I Option, a preliminary mechanical layout will be developed. This layout will include specifications for gun, magnet, and collector to form the foundation for the Phase-II engineering plan