Perrier Frédéric, Aupiais Jean, Girault Frédéric, Przylibski Tadeusz A, Bouquerel Hélène
Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Univ. Paris Diderot, CNRS, F-75005 Paris, France.
CEA, DAM, DIF, F-91297 Arpajon, France.
J Environ Radioact. 2016 Jun;157:52-9. doi: 10.1016/j.jenvrad.2016.03.006. Epub 2016 Mar 19.
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.
利用氡 - 222逸出法测量液体样品中的镭 - 226浓度，与液体闪烁法、α 或质谱法等技术相比仍具有竞争力。事实上，我们表明，在不进行空气循环的情况下，通过使用最佳气液体积比和适度加热，可以获得高精度。通过闪烁瓶以及足够长的信号和本底计数时间，实现了具有成本效益且高效的氡浓度测量。进行了400多次此类测量，包括39次稀释实验、成功对六种参考测试溶液进行的盲测以及110多次重复测量。在最佳条件下，对于100 mBq L⁻¹ 的活度浓度，不确定度达到5%，对于10 mBq L⁻¹ 则为10%。虽然蒙特卡罗模拟预测的理论检测限约为3 mBq L⁻¹，但保守的实验估计为5 mBq L⁻¹，对应于0.14 fg g⁻¹。该方法应用于47个天然水样、51个商业水样和17个葡萄酒样品，表明它可能是其他方法难以测量的液体的一种选择。在没有电力供应的偏远地区，可以使用太阳能板对闪烁瓶进行计数。因此，这种便携式方法已证明对众多天然液体具有足够的准确性，在地质和环境问题中可能会有用，其额外的好处是它可以应用于偏远地区以及样品无法运输的情况。
