Design of a Sheet Beam Electron Gun and a Depressed Collector for Terahertz TWT

A sheet beam electron gun and a depressed collector for a 0.34 THz sheet beam traveling wave tube amplifier are designed. The beam current of the designed sheet beam electron gun is 0.365 A at 23 kV voltage. The sheet beam size at the beam waist is 0.2 mm $\times$ 0.05 mm. The transmission of the electron beam over 3.6 mm in distance can attain 100%. The beam compression ratio is 21 when the beam trajectory is relatively smooth with good laminarity. The final optimized results show that the efficiency of the axisymmetric five-stage depressed collector can reach about 80% which can meet the design requirements.