Design and Analysis of Electron Optics System for 0.67 THz Staggered Grating Backward Wave Oscillators

The electron optics system (EOS), which includes the electron gun and focusing system, is the core of backward wave oscillators (BWO). This paper presents a simulation and analysis of the EOS of a 0.67 THz BWO. The design process for the electron gun and Periodic closed magnetic focusing system is described. First, the initial parameters of the electron gun were obtained using the Tiwary method and MATLAB. After further simulation and debugging, the circular electron beam electron gun with operating voltage of 23.8kV and current emitted of 18.2mA was designed. Second, to reduce the device's size and weight, the Periodic closed magnetic focusing magnetic field structure matching the electron gun was adopted, making the stable transmission distance of the electron beam greater than 30mm, and the channel radius is 0.07mm.