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Preprints
https://doi.org/10.5194/egusphere-2023-2680
https://doi.org/10.5194/egusphere-2023-2680
21 Nov 2023
 | 21 Nov 2023

Full characterization and calibration of a transfer standard monitor for atmospheric radon and thoron measurements

Roger Curcoll, Claudia Grossi, Stefan Röttger, and Arturo Vargas

Abstract. In this work a full characterization of the new user-friendly version of the Atmospheric Radon MONitor (ARMON), used to measure very low activity concentrations of the radioactive radon gas in the outdoor atmosphere, is carried out. The ARMON is based on the electrostatic collection of 218Po+ particles on a semiconductor detector surface. A main advantage of this instrument is offering high resolution alpha energy spectra which will allow to separate radon progeny (210Po, 218Po and 214Po). The monitor feature may also allow measurements of thoron (220Rn) by collection of 216Po+.

In this work the physical principle, the hardware configuration and the software development of the automatic and remotely controlled ARMON, conceived and constructed within the MAR2EA and the traceRadon projects, are described. The monitor efficiency and its linearity over a wide spam of radon concentration activities has been here evaluated and tested using theoretical as well as experimental approaches. Finally, a complete budget analysis of the total uncertainty of the monitor was also achieved.

Results from the application of a simplified theoretical approach shows a detection efficiency for 218Po+ of about 0.0075 (Bq m‑3)-1 s-1. The experimental approach, consisting of exposing the ARMON at controlled radon concentrations between few hundreds to few thousands of Bq m-3, gives a detection efficiency for 218Po+ of 0.0057 ± 0.0002 (Bq m-3) s-1. This last value and its independence from the radon levels was also confirmed thanks to a new calibration method which allows, using low emanation sources, to obtain controlled radon levels of few tens of Bq m‑3.

The total uncertainty of the ARMON detection efficiency obtained for hourly radon concentration above 5 Bq m-3 was lower than 10 % (k=1). The characteristics limits of the ARMON were also calculated, being those dependent on the presence of thoron in the sampled air, and a value of 0.132 Bq m-3 was estimated in thoron absence. Current results may allow to confirm that the ARMON is suitable to measure low-level radon activity concentration (1 Bq m‑3 – 100 Bq m‑3) and to be used as transfer standard to calibrate secondary atmospheric radon monitors.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
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Journal article(s) based on this preprint

21 May 2024
Full characterization and calibration of a transfer standard monitor for atmospheric radon measurements
Roger Curcoll, Claudia Grossi, Stefan Röttger, and Arturo Vargas
Atmos. Meas. Tech., 17, 3047–3065, https://doi.org/10.5194/amt-17-3047-2024,https://doi.org/10.5194/amt-17-3047-2024, 2024
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Short summary
The new version of the Atmospheric Radon MONitor (ARMON) is presented. The monitor efficiency...
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