Bayard-Alpert (B-A) ionization gauges are hot-filament style devices used to measure pressures below 1 x 10-3 Torr. Recent developments in this technology have improved the accuracy of these devices, at these pressures, to the 4% to 6% range, improved the performance relative to the x-ray limit, and provide greater reliability with more options for filament materials. In addition, degassing techniques allow B-A gauges to provide lower and more reliable pressure readings.
This technical note discusses the different types of Bayard-Alpert gauges, basics of operation, components of a B-A gauge, and degassing techniques.
