| 摘要 |
974,962. Velocity-modulated tubes. C.S.F.- COMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL. Jan. 18, 1963 [Jan. 19, 1962], No. 2349/63. Heading H1D. A rotationally-symmetric electron gun includes a thermionic cathode, comprising a number of emissive surfaces separated from each other by non-emissive intervals, and an anode, one of the two electrodes surrounding the other. Electrons emitted by the cathode are concentrated into a tubular beam rotating about itself by an axial magnetic field produced by coil 6, and by radial and axial electric fields. As shown, the electric fields are produced between cathode 1, Fig. 1, and anode 2, and between electrodes 3 and 4. The positions of the cathode and anode may be reversed, the anode being conical and the cathode internally emissive. The cylindrical cathode may comprise annular, or axially-extending, emissive bands separated by annular grooves or axiallyextending baffles. Alternatively, rectangular emissive surfaces 13, Fig. 5, may be provided between mutually-perpendicular grooves 14 or within the meshes of a non-emissive grid 14. The electron gun may be used in M-type travelling-wave tubes having symmetry of revolution or in O-type tubes or klystrons, Figs. 7-9 (not shown). |
