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Ionising radiation protection

Protection and environmental level calibration service

Expert calibration

NPL's protection-level calibration service is tailored for ionisation chambers used as secondary standards or instruments required for measurement of the greatest accuracy. Calibration of either an ionisation chamber alone or as a complete instrument is available.


  • Calibrated directly against the NPL air kerma primary standards or via specially constructed transfer chambers.
  • X-ray qualities in accordance with ISO 4037 narrow spectrum series (see table below).
  • 60Co, 137Cs and 241Am radionuclides.
  • Air kerma rates in the range 5 mGy/hr to 50 mGy/hr


  • Calibrations are carried out during October to December each year by arrangement.
  • Under the terms of a EUROMET agreement, calibrations with 4 MeV to 7 MeV X-rays may be undertaken at the Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany. Enquiries in this case should be directed to Dr Sigmund Guldbakke at PTB (Tel: +49 531 592 6211)

Don’t see what you are looking for? Our diverse skill set enables us to provide bespoke solutions. Please contact us to discuss your requirements.

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