Ionisation vacuum meter of cylindrical form - has ionic trap wire within anode coil wire

摘要

The ionisation vacuum chamber comprises a base cap, or flange (1) which contains electrical contact wires (2-6). The first pair (2, 3) a feeders to the cathode (7) which is carried by a stiff side support wire. Another two wires (4, 6) are terminals for a thick wire anode coil (10). The central wire terminal is for an ion trap wire, which may be one one of a number of special shapes, typically coiled, S or Z shaped or be a pair of close set parallel wires. A centrally symmetric logarithmic gradient field is created between the trap and the anode. The effect is based on the Bayard-Alpert principle.