GB741189A - Improvements in and relating to electron flow devices - Google Patents

Abstract

741,189. X-ray tubes. GENERAL ELECTRIC CO. July 9, 1953 [July 19, 1952], No. 19069/53. Class 39 (1). A getter comprises a body of zirconium secured to a tantalum mounting member, which member is supported on an electrode so that the zirconium is in spaced heat-exchanging relationship with it. In the application shown, 19 is the rotating anode, mounted on a shaft 35, of an X-ray tube. The zirconium getter is in the form of a washer 39, secured to a supporting tantalum washer 40. This latter is sprung into a groove 37 on the shaft, closely behind the anode, and being heated by it; the washers are split, as at 41, for ease of attachment. The tube envelope may be made by joining together three pre-formed sections of pressed glass, of precisely predetermined configuration and wall thicknesses; these are sealed together at 15-J and 17-J. The wall thicknesses may taper, as at 15 and 11. A thin window may be formed at 71 by forcing part of the glass envelope outward at this point, and then grinding off the projecting glass flush with the remaining surface. The cathode structure is housed inside a shell 13 which protects the seals and connections against stray electron bombardment. The cathode may comprise two filaments, mounted in grooves in a steel block, Fig. 4 (not shown). It is necessary for one of the filament leads passing through the block to be insulated from it, one method being shown in Fig. 10. The lead 47 passes through a metal sleeve 54 which is surrounded by an insulating body 50. This is held in a cup 51, of which a rim 52 is welded to the steel block. The end of the lead 47 is welded to the supply lead 61. If this is stranded, as at 62, the welded end may be tipped with a ferrule 621.