Abstract: In a traveling wave tube device of the type comprising a helix which causes a microwave power to interact with an electron beam and a periodic permanent magnet assembly for focusing the electron beam, there are provided a plurality of annular permanent magnets and a plurality of pole pieces which are alternately disposed between input and output member of the microwave. The permanent magnets and pole pieces define annular recesses and a plurality of troidal metal spring rings are disposed in each recess in thermal contact with the permanent magnets and a carbonaceous coating coated on a pumped enclosure containing the helix.

Abstract: A solid heat-dissipating member having an axial aperture to slidably receive a collector of a traveling-wave tube, includes at least one radial hole opening to the axial aperture. A contacting element having a spherical surface is accommodated in the radial hole so as to be held in pressure contact with the collector under the action of a biasing spring arranged in the radial hole. The collector can be held in good thermal-conducting relation with the heat-dissipating member without the danger of seizing and can be smoothly withdrawn therefrom when required.