High frequency radiation generation using pseudospark-sourced e-beam

Summary form only given. High frequency radiation sources in sub-terahertz frequency range (0.1-1 THz) are currently very attractive for both research and technical applications. To generate the high frequency radiation, a pseudospark (PS)-sourced electron beam is ideal because of its scalability accompanied with high intensity and high quality beam generation [1, 2]. The propagation of a PS electron beam is aided by an ion channel formed by the beam front resulting in no need for a guide magnetic field, which brings great simplicity and flexibility. Most recently, PS-sourced electron beam experiments were performed with beam diameters in both the millimeter and micro meter range. The 3mm beam was also diagnosed with a beam produced x-ray image. The PS beams have been applied in radiation sources from Ka to W bands [3, 4]. For further radiation generation, a klystron at 94 GHz is designed because the klystron is an ideal choice for higher frequency operation due to its operation mechanism, efficiency and robustness as well as the fact that it may be easily scaled in size as well [5]. Based on the 1 mm diameter PS-sourced electron beam experiment, a 94 GHz klystron with a drift tube of 0.2 mm diameter is expected to be driven by a beam of 15 mA at 8 kV. The klystron cavity at 94 GHz was simulated using the particle-in-cell (PIC) code MAGIC and a novel coupling structure was simulated using CST Microwave Studio. Simulation results revealed a strong amplification signal even taking into account the energy spread caused by the sweeping voltage during PS discharge.