GB977431A - Cold cathode ionization gauge - Google Patents

Abstract

977,431. Ionisation gauges. VARIAN ASSOCIATES. May 14, 1962 [May 22, 1961], No. 18508/62. Heading H1D. A cold cathode ionization gauge comprises a cellular anode electrode 36 defining a plurality of glow discharge passageways 37, an ion-collector plate 42 disposed on one side of the anode, a shield electrode 38 arranged to shield the ioncollector plate electrically from the anode electrode, disposed between the anode and ioncollector and having a plurality of apertures 40 aligned with the cells of the anode electrode and permitting the passage of ions through them, a vacuum-tight envelope 33 adapted as at 34, 35 to be connected to a structure whose pressure is to be measured, means 46 for producing a magnetic field through the anode, ion-collector and shield electrodes, and current-measuring means 49 connected to the ion-collector plate to permit measurement of the ion current to the ion-collector. Shield electrode 38 acts as a cathode, and a further cathode 39 may be provided. The further cathode 39 may be apertured, and a further ion-collector electrode provided. The apertures in the shielding plate may be covered by radially extending vanes or by wire gauze, or may be entirely a mesh screen. The apertures may be frusto-conical in shape, the larger opening being disposed facing the ioncollector.