1. Residual Gas Analyzer (RGA)
Applications of Mass
Spectroscopy (MS)

2. Residual Gas Analyzer (RGA)
1) Creates an environment with a large ion population.
2) Separates ions by their mass to charge ratio.
3) Detects ions with same mass to charge ratio.
A detector that senses ions that come through the quadrupoles
sample
Various
Carbon Monoxide
Hot wire e
Ions C O + C +
Intensity O +
The quadrupole rods direct select mass to charge
ions down middle path depending on magnetic
fields applied to pole pairs. 12 14 16 28 10 50 C O ++
Mass/charge
Note:
The intensity of first three mass to charge ratios shown are much smaller than the intensity of the 28 m/z signal.

3. quadrupoles
ion generation

4. Electromagnetic quadrupoles
Graph records the number and type of ions that reach the detector
Atoms from vacuum chamber
Detector
Electromagnetic quadrupoles
Select ions that reach detector
Ions form and are drawn
between quadrupoles
0.7
current
hot
ionizing
filament
Residual Gas Analyzer

5. Although the molecule was ionized
into three different types of ions:
The electromagnetic field around the quadrupoles only allowed the “red” type of ions to reach the detector.
The “blue” ions and the “purple” ions
crashed into the sides of the metal rods (the quadrupoles) before they could reach the detector.

6. This time the electromagnetic field around the
quadrupoles was changed.
The three types of ions were
formed but the quadrupoles only allowed the “blue” type of ions to reach the detector.
The “red” ions and the “purple” ions crashed into the sides of the metal rods (the quadrupoles) before they could reach the detector.

7. the electromagnetic field around the
quadrupoles was changed for a third time
only the “purple”
type of ions reach the detector.
The “red” ions and the “blue” ions crashed into the sides of the metal rods (the quadrupoles) before they could reach the detector.

8. Mass Spectra – Residual Gas Analysis
The quadrupole attached to this vacuum training system is used to monitor the gas composition in the vacuum system. For this application, the mass spec is called a Residual Gas Analyzer, RGA. RGA’s are used to monitor the relative amounts of different gases in the vacuum chamber.
electronics for the quadrupole mass spec
vacuum chamber
quadrupole mass spectrometer installed
specific gas source for a vacuum training system

9. Mass Spectra – Residual Gas Analysis
Many high tech consumer items are made in vacuum chambers of various sizes. There are particular gases in specific amounts required for different application processes performed in a vacuum system. A quadrupole mass spec (or RGA) attached to the vacuum system is one way to monitor the gases composition and amounts in the chamber to assure high quality control.
Quadrupole installed in a mass spectrometer application
Electronics for the quadrupole mass spec
Vacuum chamber
Specific gas source for a vacuum training system

10. Mass Spectra – RGA Spectra
Mass spectra of gases in the vacuum system are analyzed by the attached RGA image and stored on a linked computer