Design of an Electron Optics System for a $W$-Band Sheet Beam Klystron

The design of an electron optics system for a W-band sheet beam klystron was described. An elliptically cylindrical electron gun and wiggler focusing structure were adopted to produce and guide a 80-kV 4-A sheet beam with an elliptical cross section of 10 times 0.4 mm. The wiggler focusing principle was reviewed and a practical structure was presented. MAFIA was used to simulate the structure. The simulation showed that the electron beam transmission attained 100% over 100 mm in distance with a fill factor that is less than 0.6.