Design of an Electron Optics System for 220GHz Traveling Wave Tube

Electron optics system (EOS) which includes Electron gun and focusing system is a key part of Traveling wave tube (TWT). In the meantime, focusing system uses periodic permanent magnet (PPM) to reduce the weight and volume of the vacuum electron device. The results show that the passing rate of electron beam is high and its ripple is low. The optimum parameters of EOS are listed as follows: the current emitted from the surface of cathode is about 25mA when the operating voltage is 15kV, the length and diameter of drift tube are 65mm and 0.2mm, respectively.