GB357978A - Improvements in x-ray tubes - Google Patents

Abstract

357,978. R÷ntgen-ray tubes. LINDEMANN, F. A., Clarendon Laboratory, Oxford. June 30, 1930, No. 19786. [Class 39 (i).] One electrode, the cathode or the anticathode, is centrally disposed with a lead at one end only and is surrounded along most of its length by the other electrode which is permeable to X-rays throughout its length. Thin tubes may be used therapeutically instead of radium needles or tubes of small bulbous form may be used in hollow organs. The outer electrode may form the envelope of the tube or a metallic deposit on the glass or metal envelope or may be of gauze or network or a spiral winding on longitudinal wires. The inner electrode may be a wire positioned by insulating beads. When the anticathode is the inner electrode, it is of platinum substitute sealing-pin wire known as " Erkadraht " wound with a platinum strip and the surrounding cathode is of aluminium gauze with square holes. The outer electrode may be earthed or the tube surrounded by an earthed casing acting as a filter or having a window for the rays and the lead to the central electrode may be surrounded by an earthed flexible casing which may be filled with insulating material. A constant gas-pressure may be maintained by a vapour-forming substance unaffected by the electric current. The tube may be closed by an aluminium plug 9. In the Figure, cathode rays from the cathode 2 strike the anticathode 4 and the X-rays produced pass out through the anticathode.