GB685753A - Improvements in and relating to wave guides for electric discharge devices - Google Patents

Abstract

685,753. Particle accelerators; travelling wave tubes. BRITISH THOMSON-HOUSTON CO., Ltd. June 23, 1948 [June 27, 1947], No. 16881/48. Class 39(i) [Also in Groups XXII and XL(b)] A waveguide intended for co-operation with an electron or ion beam for generating or amplifying electromagnetic waves or for accelerating the beam comprises a helically formed metallic surface enclosed in and contacting a metallic cylinder and having a central opening through which the beam may pass. Preferably the helical conductor has a slanting generatrix and turns of conical shape, and is formed of thin sheet metal. In a preferred method of manufacture, Fig. 6, split centrally apertured discs 2, 4 are stacked in overlapping relation as shown and the overlapping abutting surfaces are tinned. The stack is then compressed between plates 3, 5 and heated until the tin melts and joins the discs together. The helical structure thus formed is then screwed into a tapped bore in the metal cylinder and soldered in position therein. Alternatively, the heat treated stack is wound on a conical mandrel, Fig. 7 (not shown), before being introduced into the cylinder. The complete discharge device comprises also input and output waveguides 12, 13 coupled to the helical guide by slots 11, a cupshaped anode, and a magnetic focusing coil 10. Specification 652,155 is referred to.