UHV-24 Bayard-Alpert Gauge Tube
Bayard-Alpert hot-cathode ionization gauge tubes employ a heated filament for the source of electrons. The Agilent UHV-24 has a wide range of operating pressure capabilities. It can measure pressures below 2 x 10-10 torr. Because of its small diameter and closed structure, its ionization rate is at least twice that of other ionization gauges. The small collector diameter limits the X-ray current, which also helps extend the lower pressure limit of the gauge.