Analysis of the electrostatic field distribution in the hemispherical internal cell of radon monitors to estimate the collection efficiency of Po-218

The collection efficiency of the hemispherical internal cell of radon monitors depends on many factors, with the distribution of the electric field and the relative humidity of the air being particularly important. COMSOL is used to simulate an internal cell with a plastic upper surface. Simulation results show a relatively uniform gradient of the electric field. Assuming that the electric field felt by the positively charged Po-218 ions in the internal cell is a linear function of its radial coordinate, a mathematical model of the collection efficiency is proposed. From this model, we obtained the following: 1) under the same neutralization rate and potential, the electric field gradient has little effect on the collection efficiency; 2) under the same neutralization rate, the collection efficiency increases with the potential on the cell wall. If the neutralization rate is small, then the potential value for the maximum collection efficiency is also small. At a relative humidity of 6%–10%, the collection efficiency saturates for values of the electric potential on the cell wall larger than 5 kV; 3) under the same potential, a large neutralization rate corresponds to reduced collection efficiency. At high potential, the collection efficiency is relatively less affected by the neutralization rate. Higher collection efficiency can be achieved under high potential and low humidity conditions. This study provides a theoretical foundation to design the internal cell of radon monitor for improving the collection efficiency of Po-218.

Assessment of physicochemical and radon-attributable radiological parameters of drinking water samples of Pithoragarh district, Uttarakhand

This study evaluates the quality of drinking water samples (sample size = 52) taken from various locations of Pithoragarh district, Uttarakhand. The parameters include physiochemical properties viz. total dissolved solids (TDS in mg/L), electrical conductivity/salinity (µS/cm), pH and radiological dose attributable to radon in water (µSv/y). TDS values for the tested samples varied within the range of 18–434 mg/L with average value of 148 mg/L. Electrical conductivity and pH for these samples was measured as 36–868 µS/cm (average: 296 µS/cm) and 6.8–8.2 (average: 7.2), respectively. Radon activity concentration for these water samples was measured using scintillation-based radon monitor, immediately after sampling at the location site. Radon activity concentration was measured as 0.6–81.9 Bq/L with an average value of 17.8 Bq/L. The paper also estimates the annual effective ingestion dose (µSv/y), annual effective inhalation dose (µSv/y) and total effective dose (µSv/y) attributable to radon in drinking water samples. Spatial patterns for the observed variations have also been interpreted for the dataset obtained over the terrestrial region.

Monitoring Radon Levels in Hospital Environments. Findings of a Preliminary Study in the University Hospital of Sassari, Italy

Background: The aim of this preliminary study was to measure radon concentrations in a hospital in order to verify to what extent these concentrations depend on various environmental variables taken into consideration, and consequently to determine the urgency to implement mitigation actions. Methods: The rooms where the concentration of the gas was potentially highest were monitored. Investigators adopted a Continuous Radon Monitor testing device. Qualitative and normally distributed quantitative variables were summarised with absolute (relative) frequencies and means (standard deviations, SD), respectively. As regards environmental variables, the difference in radon concentrations was determined using the rank-based nonparametric Kruskal–Wallis H test and the Mann–Whitney U test. Results: All measurements, excluding the radiotherapy bunkers that showed high values due to irradiation of radiotherapy instruments, showed low radon levels, although there is currently no known safe level of radon exposure. In addition, high variability in radon concentration was found linked to various environmental and behavioural characteristics. Conclusions: The results on the variability of radon levels in hospital buildings highlighted the key role of monitoring activities on indoor air quality and, consequently, on the occupants’ health.

An online radon monitor for low-background detector assembly facilities

Backgrounds from long-lived radon decay products are often problematic for low-energy neutrino and rare-event experiments. These isotopes, specifically $${}^{210}\hbox {Pb}$$ 210 Pb , $${}^{210}\hbox {Bi}$$ 210 Bi , and $${}^{210}\hbox {Po}$$ 210 Po , easily plate out onto surfaces exposed to radon-loaded air. The alpha emitter $${}^{210}\hbox {Po}$$ 210 Po is particularly dangerous for detectors searching for weakly-interacting dark matter particles. Neutrons produced via ($$\upalpha $$ α , n) reactions in detector materials are, in some cases, a residual background that can limit the sensitivity of the experiment. An effective solution is to reduce the $${}^{222}\hbox {Rn}$$ 222 Rn activity in the air in contact with detector components during fabrication, assembly, commissioning, and operation. We present the design, construction, calibration procedures and performance of an electrostatic radon detector made to monitor two radon-suppressed clean rooms built for the DARKSIDE-50 experiment. A dedicated data acquisition system immune to harsh operating conditions of the radon monitor is also described. A record detection limit for $${}^{222}\hbox {Rn}$$ 222 Rn specific activity in air achieved by the device is $$0.05\,\hbox {mBqm}^{-3}$$ 0.05 mBqm - 3 (STP). The radon concentration of different air samples collected from the two DARKSIDE-50 clean rooms measured with the electrostatic detector is presented.

RADON CONCENTRATION IN SOIL AND GROUNDWATER OF WEST COASTAL AREA, BANGLADESH

On-site radon concentration has been measured in soil gas and ground water using AlphaGUARD PQ2000 PRO (Saphymo, Germany) radon monitor at the west coastal area of Bangladesh. The measured radon concentration in ground water samples is in the range of 1.41 ± 0.29 to 3.2 ± 0.59 Bq/l with the mean value of 2.33 ± 0.50 Bq/l, which lies within the safe limit recommended by UNSCEAR (2008). The total annual effective dose estimated due to radon concentration in ground water ranges from 3.85 to 8.74 μSv/y with the mean value of 6.37 μSv/y, which is lower than the safe limit set by WHO (2004) and EU (1998). In soil samples, radon concentration has been measured at three different depths (0, 20 and 40 cm) in each location. The highest and the lowest concentrations are 4790 ± 51 and 10 ± 04 Bq/m3 at 40 and 0 cm (surface) depth, respectively, which lie within the natural background levels.