A residual gas analyzer (RGA) is a small/rugged mass spectrometer designed for process control and contamination monitoring in vacuum systems. Utilizing quadruple echnology, there exists two implementations, utilizing either an open ion source (OIS) or a closed ion source (CIS). RGAs may be found in high vacuum applications such as research chambers, surface science, accelerators, scanning microscopes, etc. RGAs are used in most cases to monitor the quality of the vacuum and easily detect minute traces of impurities in the low-pressure gas environment. These impurities can be measured down to 10^-14 mbar levels, possessing sub-ppm detectability in the absence of background interferences.
MKS Instruments have a wide-range of RGA's suitable for atmospheric to UHV vacuum requirements.