Design of a large-orbit electron gun with gradual reversal magnetic field for a W-band permanent magnet peniotron

Abstract

This paper demonstrates the operating characteristics of an axis-encircling large-orbit electron gun and a corresponding permanent magnet system of a W-band peniotron. The practical novel large-orbit electron beam with axial velocity spread of 5.17%, transverse velocity spread of 1.28%, guiding center deviation ratio 10.7%, and high velocity ratio 2 is designed. The main advantages of such a peniotron in the large-orbit configuration with a permanent magnet system are its compact size, reduced operational gap, and lower cost. Critical characteristics, such as acceleration voltage and the relative axial position of the magnetic system and electrode system have also been well examined and it is shown that a careful control of them is important for the device performance.

Acknowledgment

This work is supported by the National Natural Science Foundation of China (Grant No. 60971065).