| 摘要 |
1535314 Ionization manometers BOC INTERNATIONAL Ltd 14 April 1976 [6 Feb 1975] 5070/75 Heading HID A high-vacuum ionization gauge of the coldcathode Penning type comprises a source of charged particles situated inside the gauge but outside the discharge chamber 7 on the side remote from the inlet 31 for gas or vapour. The discharge chamber is defined by cylindrical cathode members 8 surrounding the end of an anode rod 16 which extends through a glass seal 26. A radioactive source may consist in a coating of thoria on a shield 28 protecting the glass seal 26, or it may consist of a wire made of the radioactive isotope of nickel arranged in an internal circumferential groove of the container 2. Such a wire may comprise a core of non-radioactive nickel with a coating of radionickel covered by a further coating of inert nickel. |
