Feasibility of in Situ Radon Monitoring Using Common Gm Counters

Abstract

Most of the detectors used for radon measurements rely on registering the alpha-rays coming from the 222 Rn decay itself and those from its daughters 218 Po and 214 Po, as well. Although active alpha-detectors have very low background and good efficiency, they are relatively expensive and are not well suited for field work due to their sensitivity to the ambient air humidity. In this work, an alternative possibility for in situ systematic measurements (monitoring) of radon concentration is investigated. It is suggested to use simple and wide spread detectors -Geiger-Mueller (GM) counters which are sensitive to beta/gamma radiation of 222 Rn daughters 214 Pb and 214 Bi. Long term measurements of the radiation background in uninhabited dwelling rooms were performed using simultaneously a classical radon alpha-particles detector (based on an ion chamber) and a beta/gamma detector (GM counter); the basic meteorological parameters at the site were also monitored. A very high correlation between the response of both detectors was found (r 2 ~0.9) which indicates that the radon monitoring can be successfully performed by means of cheap and moisture resistant GM counters. The drawbacks and the limitations of this method are also discussed.