GB472583A - Improvements in or relating to electron discharge devices - Google Patents

Abstract

472,583. Thermionic valves; electric resonators. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. March 1, 1937, No. 6092. Convention date, Feb. 29, 1936. [Classes 39 (i) and 40 (iii)] An electron-discharge device for use at high frequencies comprises a U-shaped member, the legs of which are of large cross-section and mass, the inner faces of the legs being closely spaced, flat and parallel; a pair of anode segments at the free ends of the legs on the inner surfaces thereof and having oppositely disposed semi-cylindrical surfaces providing a cylindrical chamber, the axis of which is parallel to the flat surfaces of the U-shaped member and contains a straight thermionic cathode. In the split-anode magnetron shown in Fig. 1, the U-shaped member 14 has its ends 18 formed into semi-cylindrical anode surfaces which surround the axiallv disposed filamentary cathode 20. The outer surface of member 14 is coated with carbon to increase radiation, the inner parallel faces and the thin edge strips 17 being left uncoated. The assembly is supported by an upper mica spacer 26, and a lower mica spacer 27 carried on a glass or ceramic cross 24 supported on the cathode leads 13. Supports or leads 22 for the ends of the member 14 are carried on the cross 24. A pair of non-magnetic shields 21, carried on the cathode leads, protect the envelope from the impact of electrons concentrated thereon by the longitudinal magnetic field set up by coils 28. The shields may be replaced by a single cylinder. A flexible connection 25 supplies the anode voltage. In a modification, the U-shaped member is secured to a metal portion of the envelope which may be merely an end plate or, as in the form shown in Fig. 5, may be a cup-shaped member 32 surrounding the assembly. In this form a cooling jacket 34 is provided.