Abstract:
A sputter-ion pump for use in combination with an electron tube having at least one thoriated tungsten cathode comprises a vacuum envelope and a getter-cathode within the envelope. The getter cathode comprises a first cathode member consisting of at least one reactive material selected from the group consisting of titanium, zirconium, thorium, tantalum, niobium and vanadium. A second cathode member, consisting, e. g. , of a reactive material and carbon, provides a recarburizing atmosphere for forming, in situ, a tungsten carbide layer on the thoriated tungsten cathode of the electron tube so as to increase the life of the electron tube.