| 摘要 |
PURPOSE:To obtain a vacuum gauge constituted so that a negative ion is formed by adhering an electron having extremely small kinetic energy to a gas molecule and collected by an ion collector to be measured, by mounting a negative ion forming device, an ion acceleration electrode, an ion collector and a magnet applying a magnetic field vertical to the axial direction. CONSTITUTION:A filament 11 for generating a thermoelectron is concentrically arranged in a cylindrical electrode 10 and the potential thereof is kept higher by several volts than that of the electrode 10 by a power source 16 and a nega tive ion forming device is constituted by both of them. An ion acceleration electrode 12 is concentrically arranged in front of the electrode 10 and the filament 11 in the axial direction and the potential thereof is kept higher by several ten volts than that of the electrode 10 by a power source 17. Further, an ion collector 14 is arranged further in front of the ion acceleration electrode 12 to be earthed through a high resistor 18. Magnets 15 are respectively ar ranged above and below the vacuum container 22 between the electrode 12 and the collector 14 and applies a magnetic field vertical to the axial direction.
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