GB634703A - Electron discharge devices - Google Patents

Abstract

634,703. Electric discharge devices. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. June 26, 1945, No. 16330. Convention date, Nov. 22, 1943. [Class 39 (i)] An electric discharge device, Fig. 1, includes an indirectly heated cathode 11 for providing a stream of electrons, a receiving electrode 12, and a deflecting electrode assembly 17, 171 comprising a plurality of electrode elements 18, which may be made by slotting a solid block of metal, spaced apart along one side of the path of said stream and a second plurality of electrode elements 18 similarly spaced apart along the opposite side of the said path, with an element of either plurality opposite to an element of the other plurality and adjacent elements of either plurality connected together so as to constitute a plurality of open-ended cavity resonators 19 with their open ends adjacent to the path of the stream. Adjacent electrode elements 18 of either plurality are spaced apart a distance equal to the distance travelled by an electron during a half period of the operating frequency of the device. The depth of the slots 19 between adjacent electrode elements of either plurality is equal to a quarter of a wave length at the operating frequency. In order to ensure that the electrode elements are properly phased during operation cross connecting straps 21, 22 are provided. These straps may be continued down the length of the deflecting electrode assembly, positively to lock all cavities 19 for 180 degree phase difference. A beam-forming element 13 at cathode potential, a focussing electrode 14, a double-apertured electrode 15, an electrode 16 for suppressing secondary electrons and a coaxial input line and loop 20 are also provided. The device may be used as a converter or amplifier. Typical voltages for the various electrodes are given. Electrode 12 may be used as a secondary emitter and electrode 16 as a collector. In the construction shown in Fig. 3 a coaxial line cavity resonator is used instead of the collector 12 comprising an inner conductor 31 and an outer casing 30 provided with an aperture 32 into which the electron beam may be directed. The resonator may be used to provide frequency multiplication. The output may be taken by the coaxial line 33.