Electron Beam Emission and Interaction in 0.3-THz Gyrotron for Second Harmonic, CW Operation

This paper describes the design of a 0.3-THz gyrotron at second harmonic operation. The interaction cavity design and the beam-wave interaction computation are carried out for TE0,6 mode by using the particle-in-cell electromagnetic simulation approach. The simulation results confirm >6-kW output power with efficiency similar to 17% by using an electron beam with accelerating voltage 20 kV and current 2.0 A. To achieve the required electron beam parameters, a triode magnetron injection gun is designed. The transverse-to-axial velocity ratio (alpha), 1.27 and the transverse velocity spread <4% are realized. Considering the fabrication and operation of the device, the parametric analysis is also performed.