Implementation of the Council Directive 2013/51/Euratom has led to a considerable increase of radon concentration measurements in drinking waters. The Directive indicates a detection limit (DL) of 10 Bq L-1, i.e. 10% of the parametric value: this restricts detection systems to gamma-ray spectrometry (DL=10 Bq L-1), liquid scintillation counting (DL=0.05–1 Bq L-1), and emanometry, i.e. scintillation cells (DL=0.3–1 Bq L-1), silicon-based detectors (DL=0.04–0.4 Bq L-1) and pulsed ionization chambers (DL=0.3 Bq L-1). In order to evaluate the reproducibility of a commercial system based on emanometry technique, a measuring set-up consisting in three replicates of such system – each consisting of a degassing circuit coupled with a pulsed ionization chamber – has been realized at the National Center for Radiation Protection and Computational Physics of Italian National Institute of Health. A custom QA/QC protocol has been developed and it will be described. It mainly addresses: i) the assembling of each component of the three circuits, ii) the sample transfer from the transport container to the degassing vessel, iii) the behavior of laboratory expert during measurements, iv) warnings to prevent water flowing back to ion chambers. All the requirements included in the protocol aim to control influencing quantities and to verify stability of the detection chain. The reproducibility of the system has been evaluated by measuring through the chains 40 different samples (120 measurements) of spring waters, with radon concentration ranging from few Bq L-1 (< DL) to about 250 Bq L-1. The coefficient of variation of the three measurements on each water sample ranged from 1% to 19%, with a median of 10%. We have also taken part, with the same measuring chains, to the radon-in-water proficiency test organized by the European Commission's Joint Research Center, obtaining good results: the three systems returned values within the arithmetic mean ±1% (standard deviation with k=1).
Reproducibility of radon-in-water measurements by emanometry technique / Di Carlo, C.; Venoso, G.; Lepore, L.; Ampollini, M.; Carpentieri, C.; Pozzi, S.; Caprio, M.; Remetti, R.; Bochicchio, F.. - (2019). (Intervento presentato al convegno 9th International Conference on Protection against Radon at Home and at Work tenutosi a Praga; Repubblica Ceca).
Reproducibility of radon-in-water measurements by emanometry technique
Di Carlo C.
Primo
;Lepore L.;Remetti R.;
2019
Abstract
Implementation of the Council Directive 2013/51/Euratom has led to a considerable increase of radon concentration measurements in drinking waters. The Directive indicates a detection limit (DL) of 10 Bq L-1, i.e. 10% of the parametric value: this restricts detection systems to gamma-ray spectrometry (DL=10 Bq L-1), liquid scintillation counting (DL=0.05–1 Bq L-1), and emanometry, i.e. scintillation cells (DL=0.3–1 Bq L-1), silicon-based detectors (DL=0.04–0.4 Bq L-1) and pulsed ionization chambers (DL=0.3 Bq L-1). In order to evaluate the reproducibility of a commercial system based on emanometry technique, a measuring set-up consisting in three replicates of such system – each consisting of a degassing circuit coupled with a pulsed ionization chamber – has been realized at the National Center for Radiation Protection and Computational Physics of Italian National Institute of Health. A custom QA/QC protocol has been developed and it will be described. It mainly addresses: i) the assembling of each component of the three circuits, ii) the sample transfer from the transport container to the degassing vessel, iii) the behavior of laboratory expert during measurements, iv) warnings to prevent water flowing back to ion chambers. All the requirements included in the protocol aim to control influencing quantities and to verify stability of the detection chain. The reproducibility of the system has been evaluated by measuring through the chains 40 different samples (120 measurements) of spring waters, with radon concentration ranging from few Bq L-1 (< DL) to about 250 Bq L-1. The coefficient of variation of the three measurements on each water sample ranged from 1% to 19%, with a median of 10%. We have also taken part, with the same measuring chains, to the radon-in-water proficiency test organized by the European Commission's Joint Research Center, obtaining good results: the three systems returned values within the arithmetic mean ±1% (standard deviation with k=1).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
