Spatial distribution of radon in an experimental room

The spatial distribution of radon and the relevance of the placement of radon detectors relative to the entry path of radon-containing air in an experimental room was investigated. A radon emanation source was used from which the air was transported with a constant air flow into the room. The radon contaminated air was released under a floor element used for electrical wiring which has multiple holes connecting to the inner volume of the room. At 36 equally spaced lattice points in the room the radon activity concentration was measured with two different solid-state nuclear track detectors of type Radonova Radtrak and Radonova Rapidos. The radon exposure on the detectors was accumulated over 72 days. Additionally, an electronic measurement device of type Saphymo AlphaGUARD was used as reference. It indicated a radon exposition of 475(1) kBq  h/m³. The detectors of type Radtrak had a mean exposition of 564(36) kBq  h/m³ and the ones of type Rapidos 496(15) kBq  h/m³. Except for one outlier both types of detector showed a homogeneous distribution of radon in the room. Therefore, we have shown that under these experimental conditions the placement of the radon detector does not significantly influence the measurement result.