Production of Well Known Pressures of Pure and Mixed Gases in the High-vacuum Range

G. Schneppe

Jan 1973 · Air Force Cambridge Research Laboratories, Air Force Systems Command, United States Force

About this ebook

A gas inlet system is described which uses the pressure-based dynamic expansion method to produce well-known pressures over the range from 1/(10 to the 4th) to less than 1/(10 to the 8th) Torr. The average absolute accuracy is about 2%, and the reproducibility better than 1%. Adjustments of the test pressure are performed within a few seconds. The gas is introduced into the test volume through a porous glass filter. Its small conductance causes a strong pressure reduction, so that the reference pressure can be measured by a compensated capacity manometer, which in turn is calibrated against an Hg-U-manometer. This technique is suitable also for measurements of active and corrosive gases. In addition, the apparatus described consists of two independent gas inlet systems which allow them to produce gas mixtures as quickly and accurately as a pure gas pressure. It is useful for mass spectrometer calibration.