GB550551A - Improvements in and relating to gettering arrangements for highly evacuated envelopes of electron discharge tubes - Google Patents

Abstract

550,551. Rontgen-ray tubes. BRITISH THOMSON-HOUSTON CO., Ltd Sept. 9, 1941, No. 11490. Convention date, Sept. 9, 1940. [Class 39 (i)] In an X-ray tube a getter is mounted within a chamber 45 formed within a head 27 in which the filamentary cathode 31 is mounted ; the head is fixed to a support 33 the outlet from the chamber 45 to the main envelope space being through an annular space 54 formed between the support 33 and a sleeve 57 attached to the:head. The getter material 85, Fig. 4,-barium and/or magnesium -is held in a wire 77 with a thin wall 79, so that when the wire is heated the getter will vapourize and past into the chamber 45 but will not deposit on the electrode terminals. The getter may be released in stages so that part may be used after the tube has been at work. The wire 77 is attached to a side wall of the head at one end 81, the other end passing through a glass seal 93 to a cable 83. A similar construction is provided for the cathode leads 91 all three passing through tubes 89 formed of an iron nickel cobalt alloy ; the cathode is supported from wires 57 held in an insulating clamp 67 which is attached to the head 27 by screws 65 holding in place the closure plate 61. The support 33 is sealed to the glass re-entrant sleeve 23 of the envelope with the intermediary of a ring 37. The chamber for the receipt of the getter may be formed in the anode.