GB909308A - Improvements in or relating to high-vacuum getter and ion pumps - Google Patents

Abstract

909,308. Dicharge apparatus. CSF. COMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL. April 13, 1959 [April 16, 1958], No. 12400/59. Class 39 (1). A high vacuum getter and ion pump comprises an envelope and an electrode system within the envelope comprising a cathode and an anode, one of the cathode and anode electrodes being formed of or coated with or supporting a reserve supply of gettering metal, such as titanium so as to act also as a gettering electrode, supply means for the cathode and anode electrodes to produce by the discharge current therebetween a detectable ionization of residual gas molecules within the envelope, the gettering electrode being arranged to be heated additionally to the heating effect, if any, of the minimum ionizing discharge current or of the heating current required to produce said discharge current to evaporate said gettering metal. The getter is of Ti, A or K. In Fig. 1, the anode 5 is a Ti helix and carries a heating current. The tube has a water jacket 7. In Fig. 3, filament 3 is a planar spiral and sectionalised anode 5 supports a Ti getter. A control grid may be provided. There may be an axial magnetic field, Fig. 4 (not shown). In another form, Fig. 5 (not shown), two Ti wall coatings act as cold cathodes and getters. The anode is an annulus containing a heater and with a getter coating. An axial magnetic field is provided. In Fig. 7 there is a control grid 11 and a helix anode 5 with a Ti getter coating. 13 is a helical cooling tube. In another form, Fig. 10 (not shown), there is an electron gun with a helix anode having a Ti getter coating and a screen mounted on its far end. The last few turns of the helix are of larger cross-section to carry more Ti. In Fig. 11, the Ti getter is carried by the hot or cold cathodes 25, 25<SP>1</SP> and anode 5 is a loop. In Fig. 13, the hot or cold cathode filaments 30 carry Ti getter helices and pass through holes in discs 27. The filaments are supported by springs 31. Anode 5 is a filament. Coil 28 produces an axial magnetic field.