Task 1.1: Development of new radioactive reference sources with stable and known radon emanation capacity

The aim of this task is to develop reference radon sources for ²²²Rn (radon) and ²²⁰Rn (thoron) with constant, stable measured emanations traceable to primary standards, based on three different technologies and to compare these sources with decaying radon gas standards at SUJCHBO, CEA and METAS. The activity ranges of the emanation sources will depend on the volumes in which they are intended to be used, but they will be capable of generating radon activity concentrations between 100 Bq/m³ and 300 Bq/m³ in the specific calibration chambers of BfS, IRSN, BFKH, METAS and SUJCHBO.
PTB will develop emanation sources based on a radium salt, and deposited on exchangeable carriers (electrodeposition), where ²²²Rn (²²⁰Rn) will be monitored relative to the activity of ²²⁶Ra (²²⁸Th). CEA will develop emanation sources based on polymers and CMI will develop emanation sources based on a similar but not identical method to CEA’s.