Multiple beam guns for high power RF applications

The U.S. Department of Energy is funding development of multiple beam electron guns for high power RF sources. The advantage of multiple beam devices is that the operating voltage can be significantly reduced from that required for a single beam. In a multiple beam device, the beam power is divided into a multiplicity of smaller beams that traverse the RF circuit in individual beam tunnels. This dramatically reduces the space charge forces that drive the beam voltage requirement. The reduced operating voltage significantly reduces the cost of the power supply system, improves efficiency, reduces the device length, lower the magnetic field required for confinement, reduces radiations hazards, and increases the bandwidth. This paper describes an eight beam gun designed to produce 100 MW of beam power for a multiple beam klystron.