Stanford Research Systems RGA100, Operating Manual And Programming Reference

Page: 39 / 362

Basic Operating Modes of the SRS RGA 2-7
SRS Residual Gas Analyzer
Important : The RGA’’s sensitivity factor for total pressure measurements is highly mass
dependent. Some residual mass discrimination takes place in the filter that results in the
mass dependence of the RGA readings being different from that of the Bayard-Alpert
gauges.
Expect to see deviations between the two gauges as the composition of the
residual gas changes.
Do not rely on the RGA total pressure measurement for critical applications where
accurate total pressure measurements are required. A high precision IGC100
controller connected to a calibrated Bayard-Alpert ionization gauge is
recommended instead.
Note: RGA Windows cannot perform total pressure measurements while the electron
multplier is activated. As a result, the total pressure window displays zero values while
the electron multiplier is being used. For more information on this subject please consult
the section titled Total Pressure Measurements in the Programming chapter of this
manual.