  The new EU Council Directive 2013/51/Euratom of 22 October 2013 introduced
limits for the content of 222Rn in drinking water. Radon analysis in water
requires a lengthy task of collection, storage, transport and subsequent
measurement in a laboratory. A portable liquid scintillation counting device
allows rapid sampling with significant savings of time, space, and cost
compared with the commonly used techniques of gamma spectrometry or methods
based on the desorption of radon dissolved in water. In this study, we describe
a calibration procedure for a portable liquid scintillation counting device
that allows measurements of 222Rn in water by the direct method, and we also
consider the case of 226Ra being present in the sample. The results obtained
with this portable device are compared with those obtained by standard
laboratory techniques (gamma spectrometry with a high-purity Ge detector, gamma
spectrometry with a NaI detector, and desorption followed by ionization chamber
detection).
