GB1160006A - Microwave Linear Beam Tubes - Google Patents

Abstract

1,160,006. Klystrons. VARIAN ASSOCIATES. 4 Dec., 1967 [5 Dec., 1966], No. 55117/67 Heading H1D. In a klystron amplifier including an interaction section for bunching the electron beam and for extracting energy from the bunched beam, the interaction section includes at least one resonant portion having a plurality of coupled periodic elements for providing a plurality of gaps that interact with the beam, the coupled elements being so dimensioned that the phase shift between R.F. electric fields across adjacent gaps is n # where n is an odd integer. In Fig. 1 the output section 34 comprises four resonant cavities defined by the end walls 35 and three discs 38, 40 and 42. The outer cavities are differently dimensioned from the inner cavities because they are differently loaded by the couplings between cavities when operated in the n # mode, and should be such as to produce equal electric fields across all the interaction gaps at the resonant frequency. The discs 38, 40 and 42 may be wheel-shaped with four radial spokes (Fig. 2A, not shown) or may include kidney shaped coupling slots which may be staggered in the three discs (Fig. 2B, not shown). An alternative construction comprises a flat substantially rectangular member with a central beam aperture (Figs. 7 and 8, not shown), and a further alternative comprises a disc with an internal annular cooling channel and a central beam aperture which also provides capacitive coupling between adjacent cavities (Figs. 9 and 10, not shown). In Fig. 3, the output waveguide 58 is coupled by an iris 57 to the penultimate cavity, and rib members 59 are provided in the walls of the cavity to compensate for the electrical distortion caused by the iris 57. An alternative construction uses three cavities with the output taken from the end cavity (Figs. 3 and 3A, not shown). The cavities are separated by drift tubes having bevelled edges and surrounded by annular members including kidney-shaped coupling apertures.