A Sensitive Vacuum Gauge with Linear Response

Abstract

A new type of vacuum gauge is described for measuring pressures in the range between zero and 10 millimeters of mercury. The gauge response is a linear function of pressure. Three sensitivity ranges are provided by a selector switch giving pressure ranges of 0 to 0.1 millimeter, 0 to 1.0 millimeters, and 0 to 10 millimeters, the second value in each case corresponding to full-scale deflection of the output meter. The gauge is actuated by the ionization current resulting from the action of the radiation from a minute amount of radium on a small portion of the atmosphere within the vacuum system.