Non-intercepting gridded guns for high power linear beam tubes

The design and performance of gridded guns for high power microwave tubes will be described. High power pulsed microwave tubes use convergent flow electron guns with high current density. Most of the microwave tubes use cathode pulsing for beam switching. To minimize weight and size of pulse modulators, a gridded gun with high amplification factor is used. For high power application a non-intercepting control grid is required. The problems that must be solved in the development of these guns are the difficulty of construction, current density variation across the cathode surface and the difficulty in obtaining high beam area convergence when high perveance operation is required. A novel solution to these problems will be described.