A residual gas analyzer (RGA) is a small quadrupole mass spectrometer, typically designed for environment analysis, process control, and contamination monitoring in vacuum systems. RGA's can monitor the quality of the vacuum by detecting (and measuring) minute traces of impurities in a low-pressure gaseous environment.
RGA's are usually mounted directly onto, and into, the vacuum chamber. RGAs perform various functions which would be difficult to obtain by other methods, including: the analysis of various gas-phase reactions, monitoring changes that occur in any gas environment, detecting vacuum leaks, and checking mass flow controllers.
Related: Residual Gas Analyzer or Leak Detector — which one is right for the job? Get the answer in our blog post, When To Use An RGA.