A system for tokamak/torus fusion research

The qRGA (quadrupole residual gas analyser) is designed for analysis of fusion system fuel delivery, and operates in TIMS mode. TIMS mode provides for control of the energy of the electrons emitted within the ionisation source, resulting in each species, D2 and 4He for example having a unique fingerprint that can be determined by qRGA. This mode of operation is known as Threshold Ionisation Mass Spectrometry (TIMS).

qRGA for tokamak/torus fusion research


At nuclear fusion research facilities, special analysis of the vacuum conditions within Tokamaks is challenging due to complex interactions of hydrogen isotopes within the Tokamak. Typically, gas purity is assessed by using RGAs and obtaining conventional mass spectrum. Validation of fusion fuel purity is complicated due to D2 and 4He occupying the same atomic mass, 4 amu (mass separation 0.0254 amu), rendering fuel validation purity problematic using conventional mass spectrometry RGA techniques.


  • Real time quantitative gas analysis in a mass range 1-200 amu
  • Sub PPM detection levels
  • qRGA operates in both conventional mass analysis and TIMS modes
  • 0.5 eV electron energy resolution over the range 0-150 eV
  • Low cost multi unit solution with radiation and magnetic shielding solutions




The system is supplied with MASsoft Professional software.

This Windows 8 compatible software allows control of the instrument via USB 2.0, RS232 or Ethernet. Provides comprehensive I/O for data output and for reading data from external devices for integration and display with mass spectrometer data.