Agilent Technologies VS Series Operation Manual page 90

VS Series Helium Mass Spectrometer Leak Detectors
8. Check to see if the leak rate signal is somewhat unstable and drifts lower than the
calibrated value. If so, lower the test port pressure with the power probe or utilize a
larger external calibrated leak.
Vacuum external calibrations were external gain factors exceed the limit of 50 due to a
high helium background (Range Stop E-8) can be performed as above, with the
exception that the background must be zeroed out prior to initializing split flow.
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