Metrological realization of the radon activity concentration in air.

In the framework of the EMPIR research project Metrology for Radon, a facility was devised that provides stable and traceable atmospheres for the realization of radon activity concentration at a high metrological level. The facility is used to calibrate and test devices for measuring radon in the air. It enables precise long-term exposures in the range between 100 Bq/m and 1000 Bq/m. The radon activity concentrations are realized with uncertainties of about 1.0 % (k = 1).