Testing of thoron cross-interference of continuous radon measuring instruments
Thoron (220Rn) may interfere with radon (222Rn) measurements, if present. We measured the thoron cross-interference (CI) signal of nine types of electronic radon instruments in constant thoron concentration without the presence of radon. The CI signal increases for the first 3 days of the exposure. Also, the initial interference signal may vary between instruments. Therefore, we propose a new test method for quantifying the thoron CI in radon measuring instruments. This includes exposure of the instrument in constant thoron concentration for a minimum of 3 days and fitting the acquired data in a simplified function, which will provide two parameters: initial and final CI.
- Smetsers RCGM, Blaauboer RO, Dekkers F, Slaper H. Radon and Thoron Progeny in Dutch Dwellings. Radiat Prot Dosimetry. 2018; 181(1): 11–14. doi: 10.1093/rpd/ncy093
- ICRP. ICRP Publication 137: occupational intake of radionuclides: part 3. Ann ICRP. 2017; 46(3/4): 314–7. doi: 10.1177/0146645317734963
- de With G, de Jong P. Impact from indoor air mixing on the thoron progeny concentration and attachment fraction. J Environ Radioact. 2016; 158–159: 56–63. doi: 10.1016/j.jenvrad.2016.02.019
- IEC. Radiation protection instrumentation – radon and radon decay product measuring instruments – part 2: specific requirements for 222Rn and 220Rn measuring instruments. International Standard IEC 61577-2. 2014.
- ISO. Measurement of radioactivity in the environment – air: radon-222 – part 1: origins of radon and its short-lived decay products and associated measurement methods. International Standard ISO 11665-1. 2012.
- Hopke PK. Use of electrostatic collection of 218Po for measuring Rn. Health Phys. 1989; 57(1): 39–42. doi: 10.1097/00004032-198907000-00005
- Michielsen N, Bondiguel S. The influence of thoron on instruments measuring radon activity concentration. Radiat Prot Dosimetry. 2015; 167(1–3): 289–92. doi: 10.1093/rpd/ncv264
- Honig A, Paul A, Röttger S, Keyser U. Environmental control of the German radon reference chamber. Nucl Instrum Methods Phys Res A. 1998; 416(2–3): 525–30. doi: 10.1016/S0168-9002(98)00788-8
- Mitev K, Cassette P, Pressyanov D, Georgiev S, Dutsov Ch, Michielsen N, et al. Methods for the experimental study of 220Rn homogeneity in calibration chambers. Appl Radiat Isotopes. 2020; 165: 109259. doi: 10.1016/j.apradiso.2020.109259
- Sabot B. Calibration of thoron (220Rn) activity concentration monitors. PhD thesis. 2015. Available from: http://www.theses.fr/2015SACLS122 [cited 2 March 2021].
- Pressyanov D, Mitev K, Dimitrova I, Georgiev S, Dutsov Ch, Michelsen N, et al. Report on the influence of thoron on radon monitors used in Europe. Final report of MetroRADON Activity 2, 16ENV10 MetroRADON. Sofia: Sofia University “St. Klimet Ohridski”; 2020.