Abstract: A coupled cavity travelling wave tube has a coupling wall/ferro-magnetic pole piece formed as an iron-copper-iron sandwich with a coolant channel therein defined at least in part by the inner copper member of the sandwich. Where the coolant channel is defined also in part by a surface of an outer ferromagnetic member, at least that surface is electroplated.

Abstract: A coupled cavity TWT comprises a hollow copper tube having a plurality of tranverse walls of iron which define cavities. The walls each include an aperture on the longitudinal axis of the tube through which an electron beam passes during operation of the TWT. Any energy dissipated by electrons colliding with the surfaces of the apertures is conducted as heat away from the walls along thermal conduction paths which include copper elongate members.

Abstract: The invention provides a linear beam tube which may be protected against high voltage arcs between the cathode and anode of its electron gun by connecting to ground a limiting impedance in a series path from said anode. The anode is carried upon the end of a ceramic cylinder which is co-axially within a conical metallic member. The end of the ceramic cylinder remote from the anode is attached to one end of said conical metallic member, the other end of which is flanged, with the flange passing through the tube envelope to provide an external termination which may be connected to ground. Resistive material is deposited in a groove in the inner surface of said ceramic cylinder to form a deposited impedance which extends from the anode over the end of the ceramic cylinder, to the end of the conical metallic member and constitutes said limiting impedance.

Abstract: A travelling wave tube is provided with a slow wave structure consisting of clover leaf cavities in which frequency selective attenuators are present in subsidiary cavities formed within the nose of a clover leaf cavity. Each attenuator consists of dielectric material loaded with attenuation material. The use of the invention enables the coupling properties of the clover leaf cavities and their resonant frequencies to be chosen to provide optimum oscillation suppression.

Abstract: A coupled cavity travelling wave tube is disclosed which has a sever including a termination wedge, a sever pole piece with a drift tube and a termination cavity member defining a rectangular waveguide. Disposed in the rectangular waveguide are preformed projections which are provided so as to engage with the termination wedge, the termination wedge thereby being sandwiched between the projections and the sever pole piece.