link to homepage

Institute of Energy and Climate Research

Navigation and service

Techniques for radical concentration measurements


The institute IEK-8 has many years of experience in the development and operation of highly sensitive instruments for measurements of trace gases in the ppb and pptv range. For OH radicals, atmospheric measurements have been achied as low as 0.01 pptv. The physical techniques that are being used are:

  • Laser induce fluorescence (LIF)
    This method allows the direct laser detection of OH radicals. HO2 and RO2 radicals can be detected after chemical conversion to OH.


  • Optical absorption spectroscopy

  • Laser flash photolysis + LIF
    Measurement of atmospheric OH lifetimes, which depend on the concentrations of atmospheric OH reactants and their OH reaction rate coefficients.
  • Chemiluminescence detection (CLD)
    for NO and NO2
  • Gas Chromatography
    for VOCs, CO, Peroxyacetylnitrate (PAN)
  • Chemical-Ionisation Mass Spectrometry (CIMS)
    This technique can be applied for a variety of trace gases (e.g. VOCs and oxygenated VOCs), which can be ionised, for example, by H3O+, Br-, NO3- ions. The measurement of HO2 radicals by CIMS is under development. VOCs and oxygenated VOCs can be be measured by PTRMS or CIMS.

IEK-8 is also operating facilities that support calibrations and data assurance in international projects and measurement networks (e.g., ACTRIS, GAW).

  • The atmosphere simulation chamber SAPHIR and the project EUROCHAMP allow instrumental tests and measurement comparisons under realistic tropospheric conditions.
  • Within Global Atmospheric Watch (GAW), IEK-8 takes the role of a World Calibration Center for

    • airborne ozone sondes and humidity sensors
      (WCCOS und ESF)
    • measurements of NOx (WCCNOx).









Dear visitor,

To make our website suit your needs even more and to give it a more appealing design, we would like you to answer a few short questions.

Answering these questions will take approx. 10 min.

Start now Close window

Thank you for your support!


In case you have already taken part in our survey or in case you have no time to take part now, you can simply close the window by clicking "close".

If you have any questions on the survey, please do not hesitate to contact:


Your Team at Forschungszentrum Jülich


Note: Forschungszentrum Jülich works with the market research institute SKOPOS to anonymously conduct and analyze the survey. SKOPOS complies with the statutory requirements on data protection as well as with the regulations of ADM (Arbeitskreis Deutscher Markt- und Sozialforschungsinstitute e.V.) and ESOMAR (Europäische Gesellschaft für Meinungs- und Marketingforschung). Your data will not be forwarded to third parties.