A triple-beam 6.7 GHz, 340 kW monotron

The low-voltage monotron oscillator described in this work comprises a cylindrically symmetric cavity operating in the TM/sub 040/ mode, excited by three axially-directed hollow beams. The cavity geometry (radius 8.42 cm, length 1.0 cm) and injection beam energy (10 keV) are determined by a one-dimensional treatment disregarding space-charge forces. A 2.5-D particle-in-cell simulation is carried out for 0.4 cm thick beams at 80 A current giving 340 kW output power at an overall tube efficiency of 14.2%.