GB543752A - Improvements in electron discharge devices - Google Patents

Abstract

543,752. Electron oscillators. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Sept. 13, 1940, No. 14183. Convention date, Sept. 13, 1939. [Class 39 (i)] In an electron discharge device wherein a beam of electrons flows through coaxial tubes 46, 47 and past a gap 55 between these tubes the defocusing effect of the electrostatic field produced by the potentials on the tubes is reduced by a magnetic field produced between the members 52, 53, Fig. 4, adjacent the gap. The tubes 46, 47 are part of a resonant tank circuit as described in Specifications 541,477 and 543,592; the tubes may consist of copper coatings on the members 52, 53, the resonator being completed by the cylinder 48 and discs 49, 50. With an accelerator electrode 44 in front of the cathode the magnet member around it may have a gap 54 to provide a field opposing the dispersal effect of the electrode 44. With the gap 73, Fig. 5, centrally of the resonator the pole pieces 52, 53 are connected to side arms 72 ; a separate electromagnet 76 is used to provide a concentrating field in front of the cathode. In a modification where the resonator is contained within an evacuated envelope the electromagnet is outside the envelope and the pole pieces have extensions passing around the side discs and outer cylinder of the resonator. The means for suppressing secondaries described in Specification 543,592 may be used. In a further construction a number of square cathodes 80, Fig. 7, with control grids 81 send beams through grid like parts 95, 96 in the co-axial tubes, the collector electrode 82 having corresponding pockets 83. The magnetic lens is produced between the gap separating the extensions 88 of the permanent magnets 92, 93. The tank circuit includes the discs 90, 91 and the non- magnetic closure 89. An accelerator electrode 84 is placed in front of the collector.