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Detector setup fails with beam error - WKB12269

Article number: 12269


  • "Beam error - too many beam intensity failures" or "Beam error - beam too weak" error occurs during detector voltage setup
  • Problem arises even when the beam for LeuEnk is stable
  • Cannot improve beam intensity sufficiently with higher flow rate or sensitivity
  • Abnormal isotopic pattern for Leu Enk (incorrect relative intensity for 2nd and 3rd isotope peaks or artefact peaks are present in between isotopes)
  • 2nd C13 isotopes (M+2) not visible


  • Xevo G2
  • Xevo G2-S
  • Xevo G2-XS
  • Synapt G2
  • Synapt G2-S
  • Synapt G2-Si
  • Synapt XS


Problem is related to excessively high or low detector voltage at the beginning of the detector setup.


  1. In the Tune page, go to the Setup drop-down menu and select System View
  2. Enter the password: access
  3. Go to the System drop-down menu (not the system 1 or system 2 tabs)
  4. Select Auto Values.
  5. If the signal is too high and shows artefact peaks after the real ones, decrease the detector voltage to remove artefacts but ensure LeuEnk is still giving a strong signal.
  6. If the signal is too low and the isotopic pattern of Leu Enk is abnormal, increase the detector voltage to reach signal in mid e6
  7. Click Update and Close.
  8. Run Detector Setup.
  9. Repeat for Negative Ion mode, if necessary.


Make sure that the beam is stable (too high desolvation temp. and gas flows can cause an unstable beam)

Nominal mass position should be adjusted as needed

Capillary voltage should not be too high as this may cause overloading of the detector

Rapid changes in detector gain are typically seen with new detectors or when the instrument has recently been switched back on after several months of inactivity

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