Table of Contents
Advertisement
Technical Information
Degas
All UHV-24 and UHV24p ionization gauges are operated and degassed at the
factory before shipment. Whether to degas the gauge after installation depends
upon the application. In large systems that take a long time to pump down, such as
several days, or will be baked for an extended period of time, degassing the gauge
has a negligible affect. Considering that the e-beam degas system used runs at a
high emission current, it may not be worth the theoretical reduction in filament life
that results from the small reduction in gas load. In small systems, where the gauge
is a larger percentage of the system surface area and gas load, there may be
benefits to using degas after installation. Gauge degassing is not generally needed
unless the goal is to reach pressures below 1x10
clean tube contamination.
If using degas, an approximately 25 minute e-beam degas duration, using Agilent
XGS controllers, is all that is needed. Extending the degas interval only serves to
heat up the surrounding chamber walls and increases the out-gassing rate from
those surfaces. Bakeout is a better way to degas the chamber walls.
Bakeout
A temperature of +450 °C is a safe maximum for repeated or extended bakeout of
the nude gauge.
Do not:
Exceed +450 °C
Expose the gauge to thermal shock
Agilent UHV-24/UHV-24p Ionization Gauge User Manual
Torr. Degas is not intended to
-8
23
Advertisement
Table of Contents
