| 摘要 |
779,733. Velocity-modulated tubes. SPERRYRAND CORPORATION. March 10, 1953, No. 6650/53. Class 39(1). The variation in the transverse de-bunching force due to space-charge repulsion in different parts of the beam owing to the different degree of bunching is compensated by making the magnetic focusing field greater at those parts where the bunching is denser. Preferably the device operates with Brillouin flow from a magnetically shielded cathode and the required magnetic field at each point is obtained by substituting the appropriate current density in the bunch at that point in the Brillouin equilibrium equation. In a cascade klystron, separate coils 8, 9, 10 and 11, 12, 13 are arranged respectively between the buncher and cascade resonators 2, 3 and the cascade and catcher resonators 3, 4 and the desired variation of magnetic field along drift tubes 6, 7 is obtained by varying the turns or current in each coil or both. A preliminary focusing coil 14 is provided. The same arrangement may be used in a travelling-wave tube or magnetic disc poles 19, Fig. 2, may be energized by coils 21 surrounding yokes 20. Alternatively the pole-pieces may form say every fifth disc 26, Fig. 4, in a discloaded delay line. The screened cathode 40, Fig. 5, and focusing ring 41 are positioned within the skirt 31 of magnetic pole-piece 30 on which is mounted anode 36. A formula is given for determining the proper position of the point A (where the beam is parallel) from data relating to the shape of the curve giving the axial variation of magnetic flux, which is stated to show a maximum at a certain distance in front of the pole-face. Specific dimensions and data in an example are given. Specification 729,812 is referred to. |
