Nude Ion Gauge & Spare Filaments

Hot Kathode Ion Gauges.
Bayard-Alpert ionization gauges have different relative sensitivities for different gas species. As a result, pressure readout provides a direct reading only for the gas for which the gauge is specified (Nitrogen). This is called a readout of Nitrogen equivalent pressure. A simple mathematical conversion of the direct pressure readout to the pressure of the nonstandard gas can be made, using the relative gauge sensitivity for the specific gas.

Pressure region.
Hot kathode ionization gauges work best in given pressure ranges. The useful range of most of these gauges start at 1.10 e-3 mBar.