| 摘要 |
<p>1,264,765. Electrode materials and processing. VARIAN ASSOCIATES. 16 June, 1970 [16 June, 1969], No. 29222/70. Heading H1D. A method of fabricating a dispenser cathode for a convergent stream electron gun comprises forming a pattern of crossing grooves 9 in the concave face of a cathode blank defining an array of cells, forming concave facet 3 in the cells and incorporating in the groove pattern a multi-apertured grid structure 8. The structure acts to focus electron beamlets through apertures 7 in a control grid 6 identical with grid structure 8. The cathode blank is of porous W impregnated first with Cu or plastics material which is subsequently removed and replaced by Ba. Grooves 9 forming a hexagonal pattern are milled, chemically etched or electrical discharge machined then circular or hexagonal facets 3 are machined or electrical discharge machined. Grid structure 8 of Mo, coated with C, Ti, Zr, or Ir to prevent electron emission, is supported in but not touching the grooves 9 by a member 11 which acts as a heat sink. Alternatively, the structure 8 is brazed with Mo-Ni or Mo-Ru in the grooves. The cathode forms part of a high convergence gun for use in linear beam tubes, e.g. as described in Specification 1,191,755.</p> |
