Random and systematic errors in the graded screen technique for measuring the diffusion coefficient of radon decay products

Abstract

Measurement data for the diffusion coefficient of radon progeny from a 1985 experiment was reexamined to give an updated report on the results of the experiment, and to identify and quantify random and systematic errors in the measurement method. The measurement technique used in the 1985 experiment was an early version of a sampler subsequently named the graded screen array (GSA). In this reexamination, the baseline value of the diffusion coefficient of 218Po from repeated sampling with the GSA was found to be 0.0523 ± 0.0086 [1 standard deviation (SD)] cm2 s−1. The SD was found to be consistent with the propagated random errors associated with adjusting the sampling flow rate, combined with those due to small-number statistics in measuring radioactivity. It was not possible to determine the width of the distribution; narrow distributions fit the data just as well as wide ones. Corrections were made to avoid systematic errors due to inlet losses and recoil losses. The former was significant but the latter was not. © 1995 American Association for Aerosol Research Published by Elsevier Science Inc.