Traceability of radon-222 activity concentration in the radon chamber at the technical university of Catalonia (Spain)

In order to provide reference 222Rn activity concentration, a device based on the alpha spectrometric measurement of 218Po collected electrostatically on a PIPS detector, has been developed and characterised. Traceability is achieved by the use of primary 222Rn standard activity inside a glass bulb obtained from the Physikalisch–Technische Bundesanstalt. Radon standard activity is then transferred to the instrument that measures the reference radon activity concentration. The instrument is used in the walk-in radon chamber of the Institute of Energy Technology at the Technical University of Catalonia in order to provide a reference atmosphere for the calibration of radon concentration detectors. Under typical environmental calibration conditions within the radon chamber, an expanded uncertainty of roughly 4% (k=2) for radon concentration is usually estimated.