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A Residual Gas Analyzer (RGA), otherwise known as a quadrupole mass analyzer (QMS), is a small mass spectrometer that operates under vacuum to measure which elements, and how much, are flying around in a vacuum chamber. 


            EV2-120-000FT Residual Gas AnalyzerImage Modified



it reads out spectra like this:

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The Y-axis represents the partial pressure that a given (molecular mass)/(molecular charge) represents within the total pressure of the chamber. 

CHP - Quadrupole Mass SpectrometryImage Added

Future sections:

data display and interpretation

negative linear scale as an artifact of firmware setting the zero

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Video File: How RGAs work

Discussion: how RGAs work and how the data can be ambiguous. 

View file
namehow RGAs work.mp4
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Future sections:

ionization continued

cracking

RGA hardware

filament

faraday cup

electron multiplier

calibration

tuning


external resources:

CERN tutorial on interpretation of RGA spectra

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