Over 50 % of naturally occurring radiation exposure is due to ²²²Rn (progenies), but traceability of measurements to the International System of Units (SI) is lacking. To address this, two new ²²²Rn sources were developed to be used as calibration standards for reference instruments. These sources were investigated by comparing their estimated calibration factors for one instrument. Despite the small differences derived, all uncertainties are well within the intended target uncertainty of 10 %.

In this work, a novel approach to deduce the release of the natural radioactive noble gas ²²²Rn from solid sources containing the isotope ²²⁶Ra is presented. Therein, supporting radioactivity measurements of the source are used in conjunction with a theoretical description of the dynamics. For radiation protection and environmental research, reliable and comparable ²²²Rn measurements, and therefore reference atmospheres of ²²²Rn, are needed. This work improves their realization.

There is a growing need in health and climate research for high-quality radon observations. A variety of radon monitors, with different uncertainties, operate across global networks. Better compatibility between the measurements is required. Here we describe a novel, portable two-filter radon monitor with a calibration traceable to the International System of Units, and demonstrate the transfer of a traceable calibration from this instrument to a separate monitor under field conditions.

Radon gas is the largest source of public exposure to naturally occurring radioactivity. Radon can also be used, as a tracer to improve indirectly the estimates of greenhouse gases important for supporting successful GHG mitigation strategies. Both climate and radiation protection research communities need improved traceable low-level atmospheric radon measurements. The EMPIR project 19ENV01 traceRadon started to provide the necessary measurement infrastructure and transfer standards.