Radon measurements during the building of a low-level laboratory

Radon measurements were provided during the different stages of building of a low-level laboratory in Belgrade. The depth of the laboratory is 12 m, equivalent to 30 m of water with an area of 45 m 2. The whole of the laboratory is hermetically lined with 1 mm Al foil and is ventilated with filtered air. Radon concentrations were measured with the CR-39 detector as well as via the gamma-ray spectroscopic measurements. The radon concentrations in the air were achieved to 20 Bqm −3 and reduction of secondary and tertiary cosmic-ray fluxes is five times when ventilation, filtering and sealing was applied.