| 摘要 |
<p>PURPOSE:To prevent reduction of advantages and life of an electron tube by covering the surfaces of a porous metal of a high fusing point except for its electron radiation surface by design with a metal layer of a high fusing point, or otherwise brazing it with a metal of a high fusing point. CONSTITUTION:The side surfaces of an impregnation type cathode 1 consisting of a cathode base body of porous tungsten having electron radiation material impregnated in it are covered with a brazing material 2 consisting of molybdenum and ruthenium alloy. At the back surface of the impregnation type cathode 1, in addition, the brazing material 2 is welded with a sleeve 3 by laser welding. The brazing material is not diffused in the surface of the side surfaces, so electron radiation from the cathode is limited to the electron radiation surface by design. Reduction of the life of the electron tube by damage to an anode or slow-wave circuit by electron radiation from surfaces other than the electron radiation surface by design can thus be prevented.</p> |
