AARST_Radon_Reporter_July_2023

12 | July 2023 RESEARCH TheConsortiumofInternational Radon Associations, (COIRA) organized an intercomparison of calibration facilities in 2019, which included 18 chambers from 6 countries and three continents. Three NRPP-classified secondary chambers in the US and three calibration chambers in Canada participated. The intercomparison used a trio of AlphaGUARD instruments (AlphaGUARDs) loaned for the project by the manufacturer, Bertin Technologies, as the tool to compare radon concentrations reported by each participating chamber. The three instruments were shipped together in a case, including background alpha track detectors (to monitor for the extremely unlikely but possible exposure during shipment), from chamber to chamber. Each chamber followed the same specific procedures and exposed the three instruments together in its chamber for at least three days. The chamber then emailed COIRA the results of its measurements during this exposure. The AlphaGUARD instruments’ measurement logs remained securely stored in the instruments’ buffers as they continued from chamber to chamber and airport to airport. After the final chamber exposure, the traveling AlphaGUARDs were shipped to Flagstaff, Arizona, where they were extensively tested in background concentrations (outdoors, encased in three layers of plastic, protected from rain in a tent) to verify correct response to near-zero concentrations and confirm that there had been no build-up of background radon during all their exposures. In addition, a final intercomparison was conducted in a high concentration enclosed indoor CANADA SPAIN commercial and primary national chamber national and regional chambers UNITED KINGDOM commercial and primary national chamber SWEDEN multiple national chambers CZECHIA national and regional chambers AUSTRALIA national and regional chambers UNITED STATES commercial chambers calibrated to the US EPA primary concentration