A Directory & Technical Resource Centre for all vacuum users
Vacuum is the great enabling technology of the 21st century. Lots of us use vacuum as a means to an end - for others the presence of a few molecules (still a big number!) is critical.
Vacuum-Resource.Org aims to offer information service and directory to all vacuum users. All website visitors can access the directory to search for suppliers in a specific technology area or geographical region.
We encourage you to register as a member to gain access to the technical resources and downloads. Please also submit your ideas and requests for what you would like to find on this website resource. We do not collect, or pass on any marketing data. It is your choice how you want to interact with the suppliers and manufacturers you find on these pages.
A Residual Gas Analyzer (RGA) is an instrument for measuring the partial pressures of gas species in a vacuum system. It is really a MASS SPECTROMETER characterised by being small, robust and low cost.
The origins of RGA date back to the Manhattan Project circa 1942, initially using a magnetic sector field to separate ions of differing charge-to-mass ratio, but nowadays it is the quadrupole mass spectrometer that is usually at the heart of an RGA.
An RGA consists of three modules:
The quadrupole mass filter is four rods (or hyperbolic electrodes) with the trajectory of ions along the central z-axis described by the Mathieu equations:
By applying RF + DC voltages to the rods, ions of one mass-to-charge ratio successfully find their way from the source (ionization) to the detector. Sweeping the RF/DC amplitude produces a mass spectrum which provides a 'fingerprint' of the ions remaining in the vacuum environment. The figure below diagrammatically shows the ion paths when the quadrupole filter is tuned to measure mass 28 ions (typically nitrogen).
RGA Benefits & Features