GB577037A - Improvements in or relating to electron discharge devices employing hollow resonators - Google Patents

Abstract

577,037. Electron discharge valves. BROADWAY, L. F. Jan. 14, 1941, No. 515. [Class 39 (i)] An electric circuit includes a velocity-modulation electron-discharge device in which a cathode surrounded by' or surrounding an annular resonator projects electrons in a number of radial directions through a gap in it, the gap being entirely open or having only a grid or grids joining its opposite edges and lying transversely of the path of the electrons, some or all of the electrons being returned through the gap by a reflecting electrode maintained at a suitable potential. An electron discharge device comprises a toroidal resonator surrounding or surrounded by a cathode which projects a stream of electrons in a number of radial directions through a gap in it, which gap is either entirely open or has only a grid or grids joining its opposite edges and lying transversely of the path of the electrons. As shown, an annular cathode 2 is mounted between disc form electrodes 3 which cause the electron beam to converge into a sheet which passes radially through a gap 5 in a toroidal resonator of dumb-bell section. The electrons are returned through the gap by a negatively-biassed pair of ring-shaped electrodes 7, which may be connected by a surrounding ring to form an electrode of U- shaped cross-section, or replaced by a ring- shaped electrode concave towards the gap 5. The portion of the resonator adjacent the electrode 7 may be substantially flat. Grids or conducting straps may join the upper and lower parts of the resonator, and the two parts may be coupled by a concentric line or other coupling when the electrostatic coupling between them is insufficient. Energy may be withdrawn by a concentric line coupling 8. A second resonator concentric with the first may be employed, and be coupled to it when the device is for use as an oscillation generator. For use as an oscillation mixer, the electrode 7 is maintained at such a potential that electrons exceeding a predetermined velocity are collected by it or by a further target electrode. The oscillations to be mixed may be applied to the same or to separate resonators. In another form a resonator of the transmission line type is used, comprising concentric cylinders extending through the glass envelope, the seal occurring at a voltage node as described in Specification 574,708. An axially-disposed cathode and focusing electrodes project radially-directed electrons through annular gaps in the two cylinders, the inner and outer peripheries of the gaps being bounded by grid-wires extending between the opposed edges of the cylinders. An annular reflecting electrode extends round the outside of the gap. A second resonator similar to the first may be arranged concentrically around it. Specification 545,146 as open to inspection under Sect. 91 also is referred to