VOLUME TRAPS - A NEW RETROSPECTIVE RADON MONITOR

A new method to trace back average radon concentrations in dwellings o ver several decades in time has been developed. This retrospective rad on monitor is based on the measurement of the alpha activity of Po-210 deposited in volume traps, e,g,, spongy materials used for mattresses and cushions, Polyester samples with different densities have been ex posed to radon-laden air, The exposures correspond to characteristic r adon concentrations between 390 Bq m(-3) and 3.9 kBq m(-3) over a 20 y period, The precision in converting the Po-210-signal to the radon ex posure has been improved by more than one order of magnitude compared to other common techniques. It is shown that this very sensitive metho d may be applied to almost all types of volume traps used in household s.