GB1053861A - - Google Patents

Abstract

1,053,861. Travelling wave tubes. VARIAN ASSOCIATES. Dec. 16, 1963, No. 49615/63. Heading H1D. A travelling wave tube having an electron beam focused by a periodic permanent magnet stack has an arrangement for preserving the continuity of the magnetic field in the vicinity of input and output waveguide structures and a removable collector-cooler structure, wherein the axis of the electron beam and the axis common to the periodic magnetic field may be selectively aligned. As shown, an output waveguide 26 has parallelpiped magnets 18 arranged with their physical axes parallel to the waveguide axis, but magnetized so that their broad faces are polarized in an opposite sense to each other. The magnets 18 cooperate with rectangular polepieces 16, and betweentheseand the periodic permanent magnet stack formed by annular magnets 2 and annular polepieces 4 is arranged a larger diameter annular magnet 12 and a larger diameter polepiece 13. The collector 81 is cooled by a removable cooler structure 82, the structure 82 being frictionally held by a collet 83 having a plurality of circumferentially spaced segments 87 separated by slots 88. The cooling structure 82 is urged on to the collet by a thumb-screw 91, and released by a flange 92 of the thumb-screw pulling against an overlying bracket 97 attached to the structure 82. The travelling wave tube 7 is held at each end by an annular ring or collet 71 with fingers 72, and may be transversely adjusted by the provision of a thumb-screw 73 acting against a spring 76. A cylindrical shield 101 is screwed over the cooling fins 96 to prevent damage to the tube.