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High-temperature Scale

Working Group 7.31


Poster about realization and the dissemination of the International Temperature Scale from 962 °C to 3000 °C
Poster WG 7.31 (in German)


The main tasks of the working group are the realization and the dissemination of the International Temperature Scale ITS-90 from 962 °C to 3000 °C as well as the realization and dissemination of the spectral radiance in  the spectral range from the ultraviolet (220 nm) to the mid- infrared (13 µm) with smallest possible uncertainties at the highest metrological level. 

For this purpose, the working group operates measurement setups for the calibration and characterization of radiation thermometers and radiation standards for temperature and spectral radiance against national standards. 

The working group thus guarantees the metrological traceability of high-temperature radiation thermometry and of source-based radiometry to the International System of Units (SI) for customers from industry and research and for other national metrology institutes.



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  • Further development of the International Temperature Scale above 962 °C based on metal-carbon high-temperature fixed points and absolutely calibrated filter radiometers
  • Development of thermodynamic temperature measurement in the high-temperature range, traceable to the primary standards “electron storage ring” (synchrotron radiation) and “cryogenic radiometer”
  • Development of new measurement methods for the spectral emissivity above 750 °C
  • Development of user-specific methods of traceable industrial hightemperature and radiance measurement, for example for:

    • aerospace  industry (≈ 1300 °C to 3000 °C)
    • refractory metals manufacturing ( > 2500 °C)
    • silicon carbide and C/C (carbon) composite materials (up to 2800 °C)
    • manufacturing of iron, steel, glass and ceramics (up to approx. 1800 °C)
    • energy efficiency comparison of infrared heating radiators

  • Development and realization of a robot-based measurement set-up for the radiometric characterization and calibration of imaging systems for spatially resolved radiance and temperature measurements
  • National and international committee work and standardization activities in the field of thermodynamic temperature measurement, radiation thermometry and thermography

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The following services are carried out in working group 7.31 in accordance with the Opens external link in new windowQuality Manual of Division 7:

  • Calibration of the radiation temperature of tungsten strip lamps and cavity radiators from 962 °C to 3000 °C
  • Calibration of radiation thermometers and thermal imagers in the temperature range from 962 °C to 3000 °C
  • Calibration of the spectral radiance of radiation sources (tungsten strip lamps, integrating sphere based radiators) in the spectral range from 220 nm to 2.5 µm
  • Calibration of the spectral irradiance responsivity of filter radiometers in the spectral range from 238 nm to 1.7 µm
  • Calibration of the integrated irradiance responsivity of thermal detectors with blackbody radiation

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