8142 Glass Bayard-Alpert

Type 8142 is a versatile gauge constructed with a rugged bifilar grid and a thoriated iridium filament. The interior of the tube is platinum coated, shielding the gauge components from electrostatic and static charges that can occur in various operating conditions. This gauge contains a burnout-resistant thoriated iridium filament. It is also available in a rugged, long-life design described in the special gauge section.



Tubulation3/4”, 1” Pyrex® or Nonex® glass or 3/4”, 1” Kovar® flanges are available
EnvelopeNonex® 7720 glass
Mounting PositionVertical
Collector.005” tungsten
FilamentThoria-coated iridium or tungsten
GridTungsten helix configuration


Sensitivity for N210/Torr
X-ray Limit2 × 10-10 Torr
Operating Pressure2 × 10-10 to 1 × 10-3 Torr
Electron-Bombardment Degas70 W
Resistance-Heated Degas6.3 V to 7.5 V @ 10 A
Bakeout Temperature250 °C

Pyrex® is a registered trademark of Corning.
Nonex® is a registered trademark of Corning.
Kovar® is a registered trademark of Westinghouse Electric Corp.