GB874674A - Ion-getter pump - Google Patents

Abstract

874,674. Discharge apparatus. HIGH VOLTAGE ENGINEERING CORPORATION. Jan. 27, 1958 [Jan. 26, 1957], No.. 2653/58. Class 39(1). An ion-getter pump for producing a high vacuum below 10<SP>-6</SP> mm. of mercury consisting of a casing containing an ion source and a vaporizer source for getter metals, particularly titanium, is characterized in that the ion source is created in one part of the casing and is in communication with the vaporizer source which is created in another part of the casing, there being no substantial restriction of the flow of gas between the two parts of the casing. In the arrangement shown, a layer of getter metal 5 is formed on the wall of a tube 1 by vaporization of titanium wires 4 wound on one or more hairpin-shaped wires 2 of high-melting-point metal such as tungsten. A connection 6 enables a specific potential to be given to the layer 5. The gas to be pumped which may bea rare gas, is ionized by a discharge device 3 of the Penning type. If a very high final vacuum of about 10<SP>-7</SP> mm. of. mercury or less is required, a heated cathode 8 is used. Otherwise, any other source of electrons, such as a radio-active preparation or a pointed cathode may be used. Other types of ion source may also be used. The vaporizer source may be directly or indirectly heated. A preliminary evacuation of the container 7 to a pressure of about 10<SP>-2</SP> mm. of mercury is effected by a backing, pump, and the getter metal 4 and tungsten wire 5 are outgassed by powerful heating. Thebacking pump is then removed and the discharge device switched on. In operation, the temperature of the vaporizer source may be maintained at a value below the vaporizing temperature of the getter metal except for repeated brief intervals when it is raised above that temperature. Owing to the separation of the vaporizer source and the ion source the electrodes of the latter are not contaminated by evaporated getter material.