Intercomparison of equipment measuring radon activity concentration in the air—an example from a hydrotechnical structure in Dobromierz (SW Poland)

The semi-conductor SRDN-3a probe, an AlphaE detector with a silicon diode in a diffusion chamber, an AlphaGUARD monitor with an ionization chamber and CR-39 track detectors had been tested simultaneously in long-term measurements conducted in the technical corridor of Dobromierz dam. The passive detectors were exposed twice: for 56 days, and 117 days, others in parallel, with a 1-h data recording interval. The data distribution was tested with the Shapiro–Wilk test and outliers in the critical region were identified using Shewhart control charts. The correctness was evaluated by a z-score test recommended by the IAEA. The characteristics of outliers for each detectors are determined by the location of the critical region (a two-sided region and a positive skew). These are 13.0% and 13.5% for AlphaE, and 9.81% for SRDN-3a. For the reference device, these are 15.8% and 10.5%. The z-score test confirm that all the detectors can be successfully used both in commercial and scientific monitoring measurements.