GB561911A - Improvements in electron discharge devices - Google Patents

Abstract

561,911. Electron beam valves. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Oct. 30, 1942, No. 15290. Convention date, Oct. 30, 1941. [Class 39 (i)] In an electron discharge device having a cathode 11 and a collector electrode 15 and between them a pair of electrodes 19 and 20 spaced axially to provide a gap across which a high-frequency field may be generated for velocity modulating the electron stream, the electrode 15 has electron receiving surfaces 17 and 18 located at different distances from the cathode and means are provided to separate the slower and faster electrons so that they all arrive at the receiving surfaces more nearly simultaneously than if the latter were at the same distance. In operation the velocities of the electrons in the beam are cyclically varied by the field in the gap between electrodes 19 and 20 and the gap 26 in the input resonant cavity 25. A projection 21 from electrode 19 enters electrode 20 and thus a radial field is set up in electrode 20 which reverses its direction in unison with the velocity varying field in the gap. The faster electrons are diverted outwardly and pass through the annular space between tubes 22 and 24 to surface 18 whereas the slower electrons proceed axially within tube 22 and are received on surface 17. An output resonance cavity 27 is provided having a gap 28 between electrodes 24 and 15. The electron beam may be first modulated by a grid 13 and the velocity modulation superimposed on this.