title: Optimized measurement of radium-226 concentration in liquid samples with radon-222 emanation.
abstract: Measuring radium-226 concentration in liquid samples using radon-222 emanation remains competitive with techniques such as liquid scintillation, alpha or mass spectrometry. Indeed, we show that high-precision can be obtained without air circulation, using an optimal air to liquid volume ratio and moderate heating. Cost-effective and efficient measurement of radon concentration is achieved by scintillation flasks and sufficiently long counting times for signal and background. More than 400 such measurements were performed, including 39 dilution experiments, a successful blind measurement of six reference test solutions, and more than 110 repeated measurements. Under optimal conditions, uncertainties reach 5% for an activity concentration of 100 mBq L(-1) and 10% for 10 mBq L(-1). While the theoretical detection limit predicted by Monte Carlo simulation is around 3 mBq L(-1), a conservative experimental estimate is rather 5 mBq L(-1), corresponding to 0.14 fg g(-1). The method was applied to 47 natural waters, 51 commercial waters, and 17 wine samples, illustrating that it could be an option for liquids that cannot be easily measured by other methods. Counting of scintillation flasks can be done in remote locations in absence of electricity supply, using a solar panel. Thus, this portable method, which has demonstrated sufficient accuracy for numerous natural liquids, could be useful in geological and environmental problems, with the additional benefit that it can be applied in isolated locations and in circumstances when samples cannot be transported.
authors.affiliation: Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Univ. Paris Diderot, CNRS, F-75005 Paris, France. Electronic address: perrier@ipgp.fr.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Perrier
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Aupiais
authors.affiliation: Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Univ. Paris Diderot, CNRS, F-75005 Paris, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Girault
authors.affiliation: Wrocław University of Technology, Faculty of Geoengineering, Mining and Geology, Division of Geology and Mineral Waters, Wybrzeże S. Wyspiańskiego 27, 50-370 Wrocław, Poland.
authors.forename: Tadeusz A
authors.initials: TA
authors.lastname: Przylibski
authors.affiliation: Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Univ. Paris Diderot, CNRS, F-75005 Paris, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Bouquerel
mesh_terms: D060766:Drinking Water / Q000032:analysis; D060587:Groundwater / Q000032:analysis; D008900:Mineral Waters / Q000032:analysis; D011834:Radiation Monitoring / Q000379:methods*; D011883:Radium / Q000032:analysis*; D011886:Radon / Q000032:analysis*; D014875:Water Pollutants, Radioactive / Q000032:analysis*; D014920:Wine / Q000032:analysis
chemical_list: D060766:Drinking Water; D008900:Mineral Waters; D014875:Water Pollutants, Radioactive; D011886:Radon; D011883:Radium
keywords: Groundwater; Mineral water; Pollution; Scintillation; Tap water; Wine