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Abstract: A new concept for passive radon monitors – “radon film badges” has been recently proposed. It uses plastic radiators of high radon absorption ability, coupled with external solid state nuclear track detector (SSNTD). First experiments and theoretical modeling revealed a remarkable potential for practical applications. In this report we present results of a dedicated experiment in which detectors were coupled with different absorbers and placed in a variety of different easy-to-carry packages. The results confirmed that radon can freely diffuse in the packages. The response of the monitors with different absorbers was determined and a good agreement with the theoretical model was found. This strengthen the basis for further research and development of this new methodology. [Copyright &y& Elsevier]

Abstract: This work presents a unified numerical model for detailed description of the measurement of activity concentrations of radioactive noble gases by absorption in polycarbonates and external beta-counting. The model combines the numerical description of the kinetics of sorption and desorption processes with Monte Carlo simulations and calculates the measurement efficiency. The numerical model is compared to experimental data for 85Kr and 222Rn and a very good agreement is found. The numerical and experimental results show that for plate polycarbonates the measurement efficiency depends on the sorption and desorption times. In the case of 85Kr measurements the numerical modelling shows that this dependence is pronounced for thick polycarbonates and short exposure durations. For large exposure times 85Kr concentration inside the polycarbonate reaches homogeneous distribution, hence the efficiency of the system stays constant with time. In the case of 222Rn measurements no homogeneous activity distribution inside the polycarbonate can be reached due to the short half-life of 222Rn. The measurement efficiency in the case of 222Rn depends slightly on the desorption time. It is also demonstrated that in the case of 222Rn the measurement efficiency could be influenced by registration of the alpha-particles of 222Rn and its progeny. This influence increases the time dependence of the efficiency on the sorption and desorption times. Therefore, this effect must always be checked for and taken into account if an accurate measurement result is necessary. The developed numerical model allows to optimize the measurements by choosing appropriate experimental conditions in terms of polycarbonate thickness and sorption and desorption times. Results from several scenarios are presented, which allow the experimenter to chose a priori the optimal exposure and measurement conditions. Finally, we present results from pilot experiments on slowing down the desorption of the radioactive noble gases from the polycarbonates. We demonstrate that cooling the exposed polycarbonates to liquid nitrogen temperature practically stops the desorption of 222Rn from the polycarbonate specimen. [Copyright &y& Elsevier]

Abstract: The practical applications of the method for retrospective 222Rn measurements by home stored CDs/DVDs need a proper metrological assurance. The specific feature of this method, as compared to other methods for retrospective 222Rn measurements is the possibility for an individual a posteriori calibration of the used CD/DVD-detectors. This paper describes a procedure to ensure the traceability of this method to a reference STAR laboratory. A set of 7 groups of CDs/DVDs were exposed to 4 reference 222Rn exposure levels. After that they were treated in the etching laboratory as ”real” detectors and the 222Rn concentrations were determined by applying an individual a posteriori calibration, correction for high track density and correction for depth at which the alpha tracks were etched. The results from all 7 groups of exposed detectors demonstrated relative variation from the reference values in the interval 3.4–23.4%. The results provide evidence that the routine measurements by the CD/DVD method warrant measurements with a relative uncertainty better than 25% and therefore this method is acceptable for large-scale applications. [Copyright &y& Elsevier]

Abstract: This article points out the ability to map retrospective 222Rn concentrations by home stored CDs/DVDs. The method employs the high radon absorption ability of the polycarbonate material of CDs and DVDs and their track-etch properties. The principle steps for the application of the method are addressed. The possibility for individual a posteriori calibration is studied, demonstrating that better than 10% accuracy in retrospective measurements is potentially achievable. Results from retrospective measurements in three different regions are shown, demonstrating the potential of the method for large-scale radon mapping. Comparison with independently evaluated retrospective 222Rn concentrations in places with known radon history was made and very good correspondence was observed. The experience indicates that the method can be used for large scale retrospective radon mapping and its applications can be expanded towards mapping of radon concentrations in water and soil gas. [Copyright &y& Elsevier]

Abstract: The remarkable ability of some polycarbonates to absorb noble gases makes them an useful tool for measurements of radioactive noble gases. In this paper the kinetic of sorption and desorption processes is theoretically and experimentally studied. A theoretical model is proposed that considers diffusion and radioactive decay. Experimental results for 85Kr, 133Xe and 222Rn are presented. They include experimental determination of the diffusion length of these radionuclides in polycarbonate and study of the time dependence of sorption and desorption processes. The experimental time dependence is in a very good agreement with the theoretical model. The conclusion is that the proposed model can be useful in practical applications. [Copyright &y& Elsevier]

Abstract: In this letter we show that the high absorption ability of Makrofol to radon could be successfully used for measurements of activity concentration of 222Rn dissolved in water. [Copyright &y& Elsevier]

This work explores the application of the liquid scintillation counting of polycarbonates for measurement of the activity concentration of radioactive noble gases. Results from experimental studies of the method are presented. Potential applications in the monitoring of radioactive noble gases are discussed. [ABSTRACT FROM AUTHOR]

Abstract: This work presents a new technique for measurement of activity concentrations of Rn-222 in water which is based on liquid scintillation counting (LSC) of polycarbonates exposed in the water. The polycarbonate material has high absorption ability to radon and when exposed in a radon-containing environment (air or water), it absorbs and concentrates radon in its volume. This property of the polycarbonate material is used for sampling 222Rn from the water. The main new element in this work is that it proposes the LSC technique for measurement of the radiation, emitted from the polycarbonate material. This radiation is due to the decay of the absorbed 222Rn and its progeny. Experimental results of LSC of polycarbonate granules and thin foils exposed in water with different activity concentrations of Rn-222 are presented. In all cases a very good linear correlation between the LS counting rate and the activity concentration of the water is found. The LSC of polycarbonates shows similar or even higher sensitivity in comparison to that of LSC of water. The estimated radon-in-water minimal detectable activity concentrations of the proposed method are similar or lower than those of the LSC and lower than those obtained by gamma spectrometry. The proposed method is simple, robust, inexpensive and avoids the need of taking water samples for laboratory analysis. It facilitates studies of the spatial distribution of 222Rn in water basins by exposure of polycarbonate specimens at different spots or depths and subsequent liquid scintillation counting. [Copyright &y& Elsevier]

Abstract: Bisphenol-A polycarbonates have a high absorption ability for noble gases that can be employed for sampling and measurement of radioactive isotopes of these gases. In this report the solubility of krypton, xenon and radon in the specified polycarbonates is determined by measurement of 85Kr, 133Xe and 222Rn absorbed in polycarbonate specimens. The found solubility is used to develop a general methodology for measurement of radioactive noble gases in air and water. The methodology is tested in pilot measurements of 133Xe in air under real conditions. The results demonstrate sufficient potential for practical applications. [ABSTRACT FROM AUTHOR]

Abstract: This work describes a new method for measurement of the activity concentrations of 222Rn and 226Ra in water by exposure of a polycarbonate detector in the water and etching it for alpha-tracks. A theoretical model that gives the in-depth distribution of tracks inside polycarbonate detectors exposed in water is developed and used to optimize the method. The presented experimental results demonstrate the feasibility of the method for measurement of activity concentrations of both 222Rn and 226Ra in water. The lower detection limit is estimated at 0.06 kBq m−3 for 30 days exposure time and is achieved without preconcentration of the water or radiochemical separation of 226Ra. The method allows radon measurements directly in the water source, which could be carried simultaneously in a large number of points. [ABSTRACT FROM AUTHOR]