Calibration and metrological test of the RadonEye Plus2 electronic monitor

Consumer-grade electronic radon monitors are increasingly utilized by users and researchers. Fast and cost-effective procedures for their metrological assurance are necessary. The metrological characteristics of 20 RadonEye Plus2 monitors were investigated. The new monitors had low background of 2.5 ± 0.5 Bq/m³. The precision error for the studied group was estimated at about 9 % and the biased error (accuracy) ranged from 3 % to 16 % for activities in the range 280–2900 Bq/m³. An excellent linearity of all monitors was observed in this range. The statistical fluctuations of the RadonEye Plus2 at 300 Bq/m³ were estimated at 9% (relative percent error). A simplified calibration procedure was successfully applied. The exposure was at activity concentration exponentially increasing with a small rate, being almost constant within a single measurement of the RadonEyes. The correction factors obtained with this procedure are in excellent agreement with those obtained through the standard procedure with exposure at different constant radon concentrations. The correction factors of the monitors ranged from 0.70 to 1.06 with an average of 0.880 and a standard deviation of 0.079. Overall, the results show that the metrological characteristics of RadonEye Plus2 are sufficient for measurements in dwellings and workplaces. However, the spread of their correction factors highlights the importance of individual calibration when measurements are made for research, legislation compliance tests or decision making.