Measurement uncertainties of long-term 222Rn averages at environmental levels using alpha track detectors.
More than 250 replicate measurements of outdoor Rn concentration integrated over quarterly periods were made to estimate the random component of the measurement uncertainty of Track Etch detectors (type F) under outdoor conditions. The measurements were performed around three U mill tailings piles to provide a range of environmental concentrations. The measurement uncertainty was typically greater than could be accounted for by Poisson counting statistics. Average coefficients of variation of the order of 20% for all measured concentrations were found. It is concluded that alpha track detectors can be successfully used to determine annual average outdoor Rn concentrations through the use of careful quality control procedures. These include rapid deployment and collection of detectors to minimize unintended Rn exposure, careful packaging and shipping to and from the manufacturer, use of direct sunlight shields for all detectors and careful and secure mounting of all detectors in as similar a manner as possible. The use of multiple (at least duplicate) detectors at each monitoring location and an exposure period of no less than one quarter are suggested.
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Jacobs Engineering Group Inc., Uranium Mill Tailings Remedial Action Project, Albuquerque, NM 87108.
D000393:Air Pollutants / Q000032:analysis*; D000396:Air Pollutants, Radioactive / Q000032:analysis*; D000512:Alpha Particles; D008906:Mining; D011336:Probability; D011834:Radiation Monitoring / Q000379:methods*; D011886:Radon / Q000032:analysis*; D012621:Seasons; D014501:Uranium
D000393:Air Pollutants; D000396:Air Pollutants, Radioactive; D014501:Uranium; D011886:Radon