Task 2.2: Investigation of the influence of thoron on radon measurements and calibrations

The aim of this task is to investigate the influence of thoron on radon measurements and calibrations through the study of the sensitivity to thoron of a large sample group of radon monitors used in Europe, in order to understand and potentially correct for the influence of thoron on the performance of the radon monitors.
A large number of radon monitors are available in the laboratories at BEV/PTP, CEA, IRSN, STUK and SUBG and continuous (active) as well as integrated (passive) measurement devices will be investigated, with each partner addressing the instruments most commonly employed by end-users in their country. The experimental study will involve exposure of monitors to reference thoron and radon plus thoron concentrations and theoretical models and analysis will also be employed to determine, understand and potentially correct for the influence of thoron on the performance of the radon monitors.