Abstract

Ion focusing vacuum gauge was applied to measure the time varying neutral gas pressure in the Heliotron D toroidal chamber.
Gas was puffed from a coaxial gun which was joined to the chamber with a thine pipe. Measurement-was done without producing plasma.
The pressure range 10^-4 to 10^-7 Torr could be measured without difficulty.
When a pulse of 50 volt hight and 10 μsec width was applied to the gauge, the increased in collecter current was 100 μA for 10^-6 Torr.