Operation of a Bayard–Alpert gauge in a uniform 0–0.16 tesla magnetic field

Abstract

The behavior of one widely used Bayard–Alpert ionization gauge in a magnetic field has been experimentally investigated for two cases: field orthogonal to, and parallel to the grid axis. Emission, grid and collector currents, and current to the wall surrounding the gauge were measured as functions of field magnitude and direction for N2 in the pressure range 5×10−8 to 2×10−4 Pa. In addition to graphical presentation of these data, a qualitative description is given of the oscillatory components observed in the collector and wall currents. The data show that the zero-field gauge sensitivity can lead to large pressure measurement errors when operating the gauge in fields as weak as 0.005 T and that under certain conditions these errors may reasonably be accounted for by first determining gauge response as a function of field.