US Patent 11517975 Enhanced electron beam generation

An electron beam source including a cathode, an anode, a means for deflecting an electron beam over a target surface and at least one vacuum pump, the electron beam source further including a contraction area arranged between the anode and the means for deflecting the electron beam where a hole in the contraction area is aligned with a hole in the anode with respect to the cathode, a first vacuum pump is arranged between the contraction area and the anode and a second vacuum pump is arranged above the anode, a gas inlet is provided between the contraction area and the means for deflecting the electron beam, wherein a first crossover of the electron beam is arranged between the cathode and the anode and a second crossover is arranged at or in close proximity to the contraction area.