Highly efficient electron beam generation in a wide-aperture discharge in helium

The paper deals with a gas discharge having electron beam generation efficiency η≅100% at a voltage U>300 V. The discharge has been realized in helium in a cell with a cathode diameter of 19.5 cm. The discharge features are a higher η as compared to other discharges, the presence of reverse bends in the voltage-current characteristics including the occurrence of a falling section, and nonmonotony in η(U) and its growth with increasing He pressure. The discharge peculiarities are explained by its photoemissive nature. The basic contribution to the photoemission is made by the emission from the resonance state excited in the secondary processes