Design and Experiment of a Sheet Beam Gun for Extended Interaction Oscillator

This paper presents the design and experiment results for a W-band sheet beam electron gun of the extended interaction oscillator (EIO). A 3D simulation has been performed, and then, the structure parameters of the electron gun have been optimized. The simulation results show that the beam waist (BW) and transmission ratio are extremely sensitive to the distance between the cathode and the focus electrode. By observing the beam waist and the beam range, the maximum beam range is up to 46 mm, which is measured at the beginning of the beam-wave interaction cavity. In addition, the thickness of the beam waist decreases rapidly when the cathode is moved along the positive axial direction by 0.03 mm. Moreover, the voltage on the focus electrode has a significant impact on the beam trajectory. At last, by considering the deviation, experiment results show that the transmission is improved to 98%.