Electron gun design for multi-beam pulsed amplifier

This paper presents the design of an eight beam electron gun using OPERA 3D code for pulsed amplifier. The electron gun has to deliver total current 560 (70×8) mA at voltage 6 kV. Each beam has a perveance of 0.15 μP making a total gun perveance of 1.2 μP corresponding to a total beam power of more than 3 kW. The cathode radius is 13.5 mm and individual emitter radius is 1.55 mm having current density 0.92 A/cm². Focusing has been accomplished through solenoid. The beam pulsing can be accomplished through beam forming electrode relatively at lower negative potential at BFE with respect to cathode. This design has an added feature of cathode protection from ion bombardment with the application of additional ion barrier anode.