High-quality electron beam with non adiabatic pumping

In this paper we report on numerical simulation and experimental test of a non-adiabatic gun which generates a high-quality annular electron beam by an electrostatic pumping method. The experimental gun geometry produces a 500 kV, 700 A electron beam with total power about 250 MW in 30 ns pulse length. Measured beam parameters are compared to numerical calculations that predict an electron velocity pitch ratio of 0.6, perpendicular and longitudinal velocity spreads of 1.5% and 0.1 %, respectively, after adiabatic magnetic compression.