Radon progeny monitoring outdoors using multiple NaI detectors

Radon progeny may be used as tracers of environmental processes. In this work, a methodology involving two NaI(Tl) detector systems for the continuous monitoring of short-lived γ-emitting radon progeny activity in atmospheric air is presented. The primary detector focuses on the γ-rays of radon progeny accumulated on an air filter during aerosol sampling, while the secondary detector monitors changes in the γ-background of the measurement site. The methodology yields measurements regarding the ²¹⁴Pb and ²¹⁴Bi atmospheric activity variability at regular and short intervals. Efficiency calibration of the measurement set-up allows for activity concentration estimations. Changes in the correlation between total γ-measurements recorded from the two detectors indicate events such as precipitation impulses, difficult to be otherwise identified, that lead to intense radionuclide deposition. Moreover, total -γ deposition modeling along with machine learning can be used to predict the γ-activity in air during intense scavenging events.