GB444945A - Improvements in x-ray tubes - Google Patents

Abstract

444,945. R÷ntgen-ray tubes. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN, Emmasingel, Eindhoven, Holland. Oct. 12, 1935, No. 28245. Convention date, Nov. 9, 1934. [Class 39 (i)] In a R÷ntgen-ray tube of the kind comprising an auxiliary electrode which, when negatively charged, exerts a spreading effect on the cathode beam, the cathode comprises two parallel juxtaposed incandescent elements, the spreading electrode being provided in the plane of symmetry between the elements. By this construction a uniformly loaded anode spot is obtained when the spreading device is in operation. In the form shown, the cathode comprises two parallel helically wound filaments 3, 4, Fig. 3, disposed on either side of a metal strip 6 forming the spreading electrode. The cathode is positioned within a shield 2 and opposite an aperture 5 therein. A shielding plate 7, Fig. 1, extends behind the filaments. Insulated leads 8, 9 pass to one end of each filament, the other ends being connected to the plate 7. The strip 6 is folded so as to grip two mica plates 16, 17 which rest in U-shaped supports 18, 19, the strip being supported from the plate 7 by an interrupted wire 14 and bead 13 and by the insulated lead 12. The continuation 24 of the cathode shield is supported from the stem by a clamp 26. The distribution of specific load in the spreadout beam is illustrated. The potential of the electrode 6 may be automatically controlled by the anode current.