Abstract: A multibeam electron tube with several approximately parallel electron beams passing through a body. Among the beams, at least some define an interbeam volume, each beam defining the interbeam volume being subjected to a perturbing azimuthal magnetic field induced by all the other beams. The tube includes an element allowing, in at least one conducting element located in the interbeam volume, flow of a reverse current in the opposite direction to that of the current of the beams, this reverse current generating, in the beams defining the interbeam space, a magnetic correction field whose purpose is to oppose the perturbing magnetic field. Exemplary embodiments of the present invention especially apply to the multibeam klystrons or traveling wave tubes.

Abstract: The disclosure relates to electron guns comprising several electrodes, including a plurality of cathodes designed for the production, from an emissive face, of an electron beam each. Each of the cathodes is surrounded by a pole piece. This pole piece is designed to convey a magnetic flux close to the emissive face of the cathode. Application to longitudinal-interaction multibeam electron tubes.

Abstract: Disclosed is an multiple-beam electron tube built around an axis (Z). These electron beams go through at least one resonant cavity (10) coaxial with this axis (Z). The beams are contained on both sides of the cavity in drift tubes (3) that end in the cavity in lips (5'), facing each other in the cavity. The spacing between two facing lips is not constant. Application especially to multiple-beam klystrons with improved output.

Abstract: A method for the manufacture of a helix-coupled vane line consists in cutting out, in a part comprising at least one channel, successive slots through the channel that extend beyond the channel so as to obtain portions of turns each fixedly joined to a vane; cutting out, in another part, a succession of fingers that are all fixedly joined to each other; connecting the turn portions to the fingers so that one end of a turn portion is connected to one end of a first finger and the other end of the turn portion is connected to the base of a second finger adjacent to the first finger; and separating the fingers from one another at their bases. Application of helix-coupled vane lines. Is most notably for crossed-field amplifiers.