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Ionising radiation

Environmental Radioactivity - Medicine - Occupational Radiation Protection - Nuclear Hazards Defence

Ionisierende Strahlung

Radon measurements

The Radon Calibration Laboratory of the Federal Office for Radiation Protection (BfS) regularly carries out comparative tests for passive radon measuring devices with solid-state track detectors or electrets.

Radon calibrating laboratory

The BfS calibrating laboratory

The Federal Office for Radiation Protection (BfS) operates an accredited calibration service laboratory of the German Accreditation Body (DAkkS) for the measuring quantities "activity concentration of radon-222 in air" and "potential alpha energy concentration of the short-lived radon decay products" (PAEC) with standards directly based on the national standards (primary standards). Routinely the calibration of measuring devices of various design is carried out at request. In addition defined concentrations of radon and its decay products are provided in closed volumes for scientific issues.


The Federal Office for Radiation Protection's (BfS) calibration laboratory (DAkkS number: D-K-15063-01-00) offers the following services:

  • Calibration of active measurement systems for radon-222 and short-lived progenies,
  • Calibration of passive, integrating measurement systems for radon-222,
  • Test of metrological properties of measurement devices and
  • testing of measurement methods.

Quality assurance

Depending on the type of measuring device, the calibration of measuring devices or the regular participation in comparative tests carried out by the Federal Office for Radiation Protection (BfS) are a fundamental requirement for the quality assurance of radon measurements. Furthermore, radon measuring services handing out passive measuring devices have to demonstrate their organisational and professional competence through accreditation or approval.

Interlaboratory comparison of passive radon measuring devices

The Federal Office for Radiation Protection's (BfS) Radon Calibration Laboratory carries out comparison tests for passive radon measuring devices. These measurements serve the purpose of quality assurance of institutions carrying out and evaluating radon measurements either for the monitoring of occupationally exposed persons or in households. German as well as international measuring institutions can participate.

The current interlaboratory comparison of passive radon measurement devices using track-etch detectors (SSNTD, in diffusion chambers) or electret ionisation chambers will take place in the 1st quarter of 2018.

Diffusion chamber

Measurement methods

Measurements of radiation exposures from Radon-222 can be performed using either passive measurement devices or direct-reading devices. Passive measurement devices include radon diffusion chambers equipped with nuclear track detectors, providing readings proportional to the radiation imparted by radon during the period of measurement. These measurement devices are particularly suitable for long-term studies covering several months. Direct-reading devices should be used to measure the current radon concentration and to study its variation with time.

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