The aim of WP1 is to develop radon gas activity standards for the realization of reference fields for radon activity concentration in air in order to calibrate radon measurement instruments traceable to primary standards in a range of activity concentrations (100 Bq/m³ to 300 Bq/m³). This range is relevant for regulations defined by the European Council Directive 2013/59/EURATOM for indoor radon concentrations at workplaces (article 54) and dwellings (article 74).
This challenge is addressed by the development of new emanation sources. The performance of these sources is demonstrated by corresponding comparisons between these new sources and the well-established radon gas standards.
To maximize the benefit for practical applications, these new sources are used in radon calibration laboratories in order to develop new procedures for the realization of reference atmospheres. Already established procedures for the calibration of active and passive radon monitors (ICRU Report 88) provide a solid base for a quality assured evaluation of the performance of the new procedures.
At the end, this work package will close a metrological gap in Europe by realizing traceable radon reference atmospheres in the range of activity concentration of 100 Bq/m3 to 300 Bq/m3, while keeping the uncertainties as small as feasible.