Detection of the decay products of radon: analysis of lead-210, bismuth-210 and polonium-210 by liquid scintillation.

Abstract

The primary purpose of this investigation was to develop a wipe test method for the analysis of the decay products of radon-222 utilizing liquid scintillation detection. Investigations were concerned with the three longer half-life daughters, lead-210, bismuth-210 and polonium-210. Analyses were performed by wiping a series of standards of known concentration off a glass plate of known area. Calibration curves were then constructed and analyzed by the Quattro Pro spreadsheet program. Unknown samples were then wiped from known areas and observed activities related to concentrations by the slopeintercept method applied to the calibration curves. Results obtained from the investigation indicated that the method was applicable on a laboratory scale when concentrations of the daughters were above the 2-3pCi/cm2 range. Comparison of measured unknown values to actual values at these levels showed that the relative accuracy of the method was approximately 15%. Relative precisions were also approximately 15%. Lower relative accuracies and precisions were obtained at higher concentrations. Application of the method at environmental levels resulted in positive values for the three radon daughters. As concentrations were lower than in the laboratory, high relative standard deviations were observed. No way of determining the accuracies for the environmental samples was available.