Design of sheet beam electron gun

Sheet beam is employed in THz devices as the beam offers an effective interaction with the RF signal. Sheet beam gun design is a challenge in achieving required flatness and laminarity over the length of RF-beam interaction. As per the published literature, sheet beam shape is obtained by using complicated shapes of cathode, BFE and anode. In the present work a planar gun geometry has been proposed. It was found that the shape of BFE has a critical bearing on the laminarity of beam. The BFE having a dumbbell shape and the anode having a rectangular slit produced good laminar beam. The work on single gun has been extended to obtain twin beams which are oppositely directed. The results are encouraging.