Equilibration correction of temporal measurements for sudden²²²Rn concentration changes

Abstract

A: 222 Rn and 220 Rn can be used as tracers of groundwater or submarine springs, and 222 Rn in water also could indicate indoor radon problems in some regions. The half-life of 222 Rn is long enough that its concentration may remain significant during transit over relatively long distances, while that of 220 Rn is not. Prior research revealed that it took about 15 min for the radon to achieve gas equilibrium at a water flow rate of 17.5 L min −1 , which is approximately equivalent to the time required for the 222 Rn-218 Po pair to approach radioactive equilibrium and is limiting in terms of measurements of sudden radon concentration change. In this work, an algorithm is applied to improve the continuous tracing of radon concentrations in the field environment. Results of a laboratory experiment analyzed applying the analysis method illustrated its ability to allow immediate identification of sharp concentration increases. In this paper we find that a precipitous drop in radon concentrations lead to improper corrected values as the result of measurement uncertainties prior to the drop, and a method using zero instead negative values for reducing the uncertainties under such condition also is proposed.