A convergent confined-flow focusing system for millimeter wave tubes

A convergent confined-flow PPM focusing system for use in a millimeter-wave coupled-cavity TWT has been designed and tested. In this paper, the design procedures that were followed to produce the electron gun and its associated magnetic circuit will be discussed. A solenoid-focused tube and a PPM beam test module were built to demonstrate the validity of the design. Test data on the beam transmission achieved in the PPM module are presented.