GB1089489A - Electromagnetic slow wave structure - Google Patents

Abstract

1,089,489. Velocity-modulated tubes; particle accelerators. COMPAGNIE FRANCAISE THOMSON - HOUSTON - HOTCHKISS BRANDT. Oct. 15, 1965, No. 43888/65. Addition to 1,014,190. Heading H1D. In a modification of the slow wave structure disclosed in the parent Specification, for use in travelling- wave amplifiers, backward wave oscillations, and particle accelerators, copper bands or metallized surfaces 3, supported on the inner peripheries of the beryllium oxide rings 2, are interrupted as at 4, adjacent bands being connected by copper bars 5, arranged such that the conductive path winds always in the same sense about the axis, to give a helix-derived structure of increased bandwidth. The beryllium oxide rings may themselves be either interrupted, as at 9, or recessed (Fig. 2, not shown) opposite the ring interruptions, to give increased helical coupling with a beam passing through the structure, and the rings may be provided with additional, smaller recesses (Fig. 3, not shown) to reduce the capacity further. In a further embodiment (Fig. 5, not shown) the connecting bars 5 make an oblique angle with the conductive annuli 3 which they connect, such that the structure approaches more closely the helical form. The beryllium oxide rings may be spaced apart by ceramic cylinders lining the metal envelope, and attenuation may be provide by coating some of them with carbon.