An International Marine-Atmospheric Rn Measurement Intercomparison in Bermuda Part II: Results for the Participating Laboratories.

As part of an international measurement intercomparison of instruments used to measure atmospheric Rn, four participating laboratories made nearly simultaneous measurements of Rn activity concentration in commonly sampled, ambient air over approximately a 2 week period, and three of these four laboratories participated in the measurement comparison of 14 introduced samples with known, but undisclosed ("blind") Rn activity concentration. The exercise was conducted in Bermuda in October 1991. The Rn activity concentrations in ambient Bermudian air over the course of the intercomparison ranged from a few hundredths of a Bq · m to about 2 Bq · m, while the standardized sample additions covered a range from approximately 2.

A high-sensitivity Rn detector incorporating a particle generator.

A particle generator has been incorporated into a two-filter Rn detector to eliminate plate-out, thus increasing the number of Rn progeny collected on the outlet filter. Recording the activity of this filter by a zinc sulphide screen and photomultiplier has enabled Rn levels as low as 0.05 Bq m-3 to be detected.