Operation and Control of a High Pressure Ionization Gauge

Abstract

This paper reviews the characteristics of a high pressure ionization gauge originally reported by Schulz and Phelps [Rev. Sci. Instrum. 28, lOSt (1957)]. The gauge is available commercially as the Westinghouse WL-7903. A brief theoretical treatment is given for the linear regime, p$t Torr. The gauge sensitivity is derived from known ionization cross sections for a number of atomic and molecular gases, including argon, krypton, and xenon. Also, an improved gauge controller circuit is described. For a given gas the controller normalizes the gauge sensitivity to unity and provides a direct reading of gas pressure on a linear scale. The controller has proved very useful in the operation of a cw :Bowing-gas laser in which 0.1 to 300 mTorr pressures occur. In addition, new experimental data are presented for argon, krypton, nitrogen, and air in the "nonlinear" range 2-500 Torr.