Design of a gridded gun and PPM-focusing structure for a high-power sheet electron beam

We describe the design of a gridded electron gun and periodic permanent magnet (ppm)-focusing structure to create and guide a 415-kV, 250-A sheet beam with a cross section of 100 mm /spl times/ 8 mm. The gun is intended for use with a 40-MW X- band sheet beam klystron for driving accelerators. Using the three-dimensional (3-D) code suite AMAZE, we designed a ppm structure that guided the beam over 80 cm with 98% transmission.