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Radiation Protection Dosimetry 45:33-36 (1992)
© 1992 Oxford University Press
Analysis of Error and Minimum Detection Limits for 222Rn Measurements
Charcoal canisters have come into widespread use for screening measurements of 222Rn, especially in residences, and public and commercial buildings. Although measurements made by the canister method are not of laboratory-grade accuracy, the method is none the less very attractive for a number of uses such as those cited above. For this reason, it is quite important to make a realistic assessment of the error inherent in this methodology and its associated detection limits. This paper reports on recent efforts made at the National Air and Radiation Environmental Laboratory (NAREL) in this regard. An important finding in this work is that both the total error and the minimum detectable level rapidly reach unacceptable levels when the diffusion barrier charcoal canister is exposed for less than 2 d. In fact, the results of the theoretical investigations reported herein indicate that the 7 d exposure period advocated by the NAREL is nearly optimum.