Radon Detectors Research Articles

Artificial neural network modeling of soil gas radon concentration on different lithologies for Southwest Nigeria

Radon is a radioactive gas and a leading cause of lung cancer among non-smokers. An indicator of the level of risk associated with radon inhalation is the Geogenic Radon Potential (GRP) - a function of the soil gas radon concentration and the soil air permeability. Data is scarce on the variation of soil gas radon and GRP across different geological formations in southwest Nigeria. This study was designed to measure and develop a generalized predictive model for soil gas radon concentration and hence GRP on different bedrocks in southwest Nigeria. Soil gas radon was measured with a RAD 7 radon detector in 150 sites randomly selected over 20 major bedrocks. Soil air permeability was derived from soil saturated hydraulic conductivity measured using a constant head permeameter on undisturbed soil samples from the same sites. The GRP was obtained using Neznal relation. A 2 × 8 x 1 Artificial Neural Network (ANN) configuration culminated in the generation of a tested and validated predictive model for soil gas radon in southwest Nigeria. For the 150 sites, the range of values for soil gas radon concentration was 0.28–47.59 kBqm−3 and a mean of 10.39 ± 12.59 kBqm−3; soils on granitic bedrocks had the highest mean soil gas radon concentration (16.89 kBqm−3) and highest mean GRP (13.71). Sediments had the highest mean soil air permeability of 39.84 × 10−12 m2. Using Neznal classification, 75.30% of the sites were of low radon hazard rating. The developed predictive ANN model had a Goodness-of-Prediction (G) of 73.53%, Average Validation Error (AVE) of 0.073, Mean Bias Error (MBE) of 0.42, and Root Mean Square Error (RMSE) of 4.62kBqm−3, respectively. The model, validated using standard procedure had G, MBE, AVE, and RMSE of 86.49%, 0.61, 0.17, and 1.65kBqm−3, respectively which is an indication of good model performance.

Afyon Kocatepe Üniversitesi Ahmet Necdet Sezer Kampüsü Bina içi Radon Konsantrasyonlarının ve Yıllık Etkin Doz Eşdeğerlerinin Belirlenmesi

People generally spend more than 90% of their time indoors. Exposure to radon in indoor environments can be a significant health problem. In this study, radon concentrations were measured to evaluate the health risks of employees and students in 6 faculty buildings in Afyon Kocatepe University Ahmet Necdet Sezer Campus and to calculate annual effective dose equivalents. Measurements were carried out in the Genitron AlphaGUARD PQ2000 PRO Radon Detector System which measures with active measurement method. The radon concentration values of the faculty buildings are 4.48-82.00 Bqm-3; mean radon concentrations were determined in the range of 20.64-30.91 Bqm-3. The average radon concentration of all buildings was calculated as 24.79 Bqm-3. The annual effective dose equivalents of 6 faculty buildings were determined in the range of 0.16-0.24 mSvy-1, and the average annual effective dose equivalent was calculated as 0.20 mSvy-1. The results were compared with the limit values recommended by the International Commission on Radiological Protection (ICRP) and the Turkish Atomic Energy Authority (TAEK) for radon gas concentrations in indoor environments. The measurement results of the radon concentrations and annual effective dose equivalents of the 6 faculty buildings on the ANS Campus were determined below the limit values allowed by the institutions.

MONTE CARLO SIMULATION OF POLONIUM ION COLLECTION IN ELECTROSTATIC FIELD FOR THE PURPOSE OF RADON DETECTOR DEVELOPMENT.

Radon detectors based on an electrostatic collection of polonium and detection of its alpha decay are a popular choice for the measurement of radon activity. Due to the nature of $^{222}$Rn decays, 88% of radon progeny have a positive charge, thus enabling their collection on an electrode. A simulation software focused on the drift and diffusion of ions in an electric field has been developed, providing a tool to study and characterise such detectors. It has been found that one such device achieves only 44% collection efficiency, caused by the loss of a large fraction of the ions before reaching the collection diode. An improvement of the design is therefore proposed, changing the placement of the sensor resulted in an simulated increase of the collection efficiency up to 93%. Preliminary measurements performed using prototypes of these detectors confirm the results of the simulations.

A preliminary study on real-time Rn/Tn discriminative detection using air-flow delay in two ion chambers in series

Due to its short half-life, thoron gas has been assumed to have negligible health hazards on humans compared to radon. But, one of the decay products with a long half-life can make it to be transported to a long distance and to cause a severe internal dose through respiration. Since most commercial radon detectors can not discriminate thoron signals from radon signals, it is very common to overestimate radon doses which in turn result in biased estimation of lung cancer risk in epidemiological studies. Though some methods had been suggested to measure thoron and radon separately, they could not be used for real-time measurement because of CR-39 or LR-115. In this study, an effective method was suggested to measure radon and thoron separately from the free air. It was observed that the activity of thoron decreases exponentially due to delay time caused by a long pipe between two chambers. Therefore from two ion chambers apart in time, it was demonstrated that thoron and radon could be measured separately and simultaneously. We also developed a collimated alpha source and with this source and an SBD, we could convert the ion chamber reading to count rate in cps.

Health risks in association with indoor radon exposure in Northeastern Romania

The radon level was assessed in houses from two rural areas localized in Northeastern Romania. Long-term measurements were performed for a period of four months using a digital radon detector, model Corentium Home, AirThings 222. In addition, for every environment included in the study, investigations concerning the building materials, the floor type, the building year and the heating system were made. Accordingly, Spearman’s correlation coefficients of the study variables were calculated. The World Health Organization recommends an upper threshold of 100 Bq/m3 as a national reference level. For both studied areas, we calculated a mean indoor radon level of more than 100 Bq/m3, but in the Tomesti-Osoi area were recorded values of over 100, respectively 300 Bq/m3 in significantly more households. Indoor exposure to radon of people in the investigated houses was found in 75 and 35.3% of the cases, respectively, above the level accepted by international recommendations, with a moderate correlation between mean radon levels and the features of the residential buildings.

Study of alpha spectrometry for detection of radon and progeny using gas micro-strip detector

In this paper, simulation of a gas micro-strip detector by using the MCNPX code, the feasibility of alpha spectroscopy for radon and its progeny has been investigated. Initially, for the verification of the code, the range of alpha particles released from 222Rn gas in the air has been obtained in the standard condition, which is consistent with the experimental results. Subsequently, the energy loss per unit path length, range of alpha particles and radon progeny was measured, then the relationship between the range, the energy and the air pressure has been achieved. Finally, the simulation results have been compared with the results of the particle range relationship, pressure and energy, and the radon spectroscopy has been performed with the studied detector. The comparison of the spectrum obtained with the simulated micro-strip detector and the experimental results shows that the introduced micro-strip detector, in addition to the ability to measure radon and daughters, also has the ability to extract the spectrum from it.

Citizen Science Approach to Home Radon Testing, Environmental Health Literacy and Efficacy.

Exposure to radon is a leading cause of lung cancer worldwide. However, few test their homes for radon. There is a need to increase access to radon testing and decrease radon exposure. This longitudinal, mixed-methods study using a citizen science approach recruited and trained a convenience sample of 60 non-scientist homeowners from four rural Kentucky counties to test their homes for radon using a low-cost continuous radon detector, report back findings, and participate in a focus group to assess their testing experience. The aim was to evaluate changes in environmental health literacy (EHL) and efficacy over time. Participants completed online surveys at baseline, post-testing, and 4-5 months later to evaluate EHL, response efficacy, health information efficacy, and self-efficacy related to radon testing and mitigation. Mixed modeling for repeated measures evaluated changes over time. Citizen scientists reported a significant increase in EHL, health information efficacy, and radon testing self-efficacy over time. While there was a significant increase in citizen scientists' confidence in their perceived ability to contact a radon mitigation professional, there was no change over time in citizen scientists' beliefs that radon mitigation would reduce the threat of radon exposure, nor was there a change in their capacity to hire a radon mitigation professional. Further research is needed to understand the role of citizen science in home radon mitigation.

New generation of highly sensitive radon detectors based on activated carbon with compensated temperature dependence

Recently patented compensation module for sensors of radioactive noble gases paves the way for novel designs of radon detectors/monitors with adsorbents, suitable for long-term measurements. The module compensates the strong influence of the temperature on the response of detectors with activated carbon or other ad/absorbents. This report describes radon detectors in which activated carbon fabric is coupled with a solid state nuclear track detector and placed in a compensation module. The module is a hermetic volume made of polyethylene foil, through which the radon diffuses. Two reciprocal trends make possible the temperature compensation: that of the radon penetration through the walls, which increases with the increase of the temperature, and that of the adsorption, which decreases. The results show that outside the module the variation of the detector response over the range of 5–35 °C is 230–305%. In contrast, inside the module the variation is reduced to 6–17%. The module also protects the sensor from humidity and thoron, keeping its sensitivity to radon 7–9 times higher than that of commonly used radon detectors. This makes the new detectors very useful for measurement of low radon concentrations in the atmosphere.

Experimental Studies to Test a Predictive Indoor Radon Model.

The accumulation of the radioactive gas radon in closed environments, such as dwellings, is the result of a quite complex set of processes related to the contribution of different sources. As it undergoes different physical mechanisms, all occurring at the same time, models describing the general dynamic turns out to be difficult to apply because of the dependence on many parameters not easy to measure or calculate. In this context, the authors developed, in a previous work, a simplified approach based on the combination of a physics-mathematical model and on-site experimental measurements. Three experimental studies were performed in order to preliminarily test the goodness of the model to simulate indoor radon concentrations in closed environments. In this paper, an application on a new experimental site was realized in order to evaluate the adaptability of the model to different house typologies and environmental contexts. Radon activity measurements were performed using a portable radon detector and results, showing again good performance of the model. Results are discussed and future efforts are outlined for the refining and implementation of the model into software.

Nanostructured scintillator developed in-house for radon detection

The scintillation properties and radiation applications of Cu doped ZnS, which were Prepared from alumina crucibles in the nitrogen atmosphere and activated at 960 °C, have been evaluated. This article deals with the structural, optical, morphological and scintillation properties of Cu doped ZnS nanoparticles. The photoluminescence spectra demonstrate that the intensity of green emission at 524 nm rises with adding Cu ions due to surface states. In ZnS, a blue emission with energy of 2.76 eV is also observed due to the self-activation. A transition from blue-green to the green emission region with increasing the concentration of Cu in the phosphor is obtained. These highly luminescent materials possess the characteristics of an emissive powder to be used for radiation detection application. The scintillation properties of this ZnS-based phosphor material were experimentally tested and compared to other recognized commercial ZnS-based phosphors. The measured sensitivity of the fabricated 600P cell towards radon gas measurements was 0.035 cpm/Bq/m3.

A straightforward approach for assessing the effectiveness of membrane materials as radon (222Rn) barriers

ABSTRACT The ubiquitous presence of the radioisotope radon (222Rn) and its short-lived progeny (218Po, 214Pb, 214Bi, 214Po) is challenging in two respects: (i) Radon is a major issue regarding health-related problems due to potentially elevated radiation exposure of humans in dwellings, and (ii) due to the mobility of radon the short-lived progeny may cause complications in radionuclide detection in laboratories. Polymer membranes are an appropriate means for effectively preventing unwanted radon migration. However, most of the published literature focusses on robust membranes made for the large-scale sealing of dwelling substructures. Membranes that are suitable (at small-scale) for sealing purposes in radionuclide detection applications are only rarely discussed. In this paper, we present a straightforward practical approach that allows the effectiveness of any membrane to be assessed for any purpose related to radon sealing. Executing the approach requires only (i) a suitable container with inlet and outlet ports, (ii) a mobile radon detector, and (iii) any type of radon source material. The approach provides a tool that allows testing any available membrane for its applicability as radon barrier sheeting.

222Rn Activity Concentration Measurement and its Radiological Risks in the Environment of Barserin Village, Erbil-Iraq

222Rn Activity Concentration Measurement and its Radiological Risks in the Environment of Barserin Village, Erbil-Iraq

Assessment of the tectonic effects on soil radon activity along the margin of the Arabian plate boundary in northwestern Syria

The main purpose of the present study is to assess the role of active tectonics in influencing the emanation level of soil radon across two tectonically active structures of the Northern Dead Sea Fault (NDSF) in northwestern Syria: namely, the Qastoon and Al-Harif fault segments. The radon measurements were basically directed by the results drawn from earlier studies of archaeoseismic and paleoseismic investigation in Al-Harif, besides integrated geophysical and morphotectonic survey at the Qastoon site. In view of that, a total of 80 soil gas radon points were measured in this work with sampling depth of 75 cm, using AlphaGUARD PQ 2000Pro radon detector. The background range of normal radon emission from local soil was determined in area located away from the influence of the tectonic disturbances. The obtained radon data were statistically analyzed and the mean values have been standardized in terms of probability of magnitude which enhances the comparison process and so facilitating the separation of normal radon variations from other anomalous or geotectonic related values. The overall results revealed remarkable occurrences of fault-associated radon anomalies with maximum peak values of ~6 to 7 times above the background, trending in accordance with the predicted traces of the fault ruptures at the Qastoon and Al-Harif, respectively.

Radon Exhalation Rates of Soil Samples from Khon Kaen Province, Thailand

Radon, which can be also detected in water, forms naturally from the decay of uranium and radium found in different amounts in soil and rock. Radon from soil gases is the main cause of health hazards. Radon exhalation escapes from the ground into the air, where radon and radon progeny decays and produces radioactive particles. When inhaled, they can damage the deoxyribonucleic acid and potentially cause lung cancer. Hence, this study measured the radon exhalation rates in soil samples from 26 districts of Khon Kaen Province, Thailand by the active detector method. The closed-loop measurement system in the active detector was made up of the electronic radon detector and a bulk chamber in a 2.8-L volume. The measurement time for each sample was 24 h. Results showed that the radon concentration in soil samples varied from 5.60 to 67.10 Bq m-3 (average: 21.94±4.55 Bq m-3). The radon mass exhalation rates ranged from 7.34 to 17.51 mBq kg-1 h-1 (average: 11.39±3.38 mBq kg-1 h-1) while the radon surface exhalation rates were in the range of 0.29 to 1.31 mBq m-2 h-1 (average: 0.81±0.90 mBq m-2 h-1). The radon surface exhalation rate of the soil samples was below the average worldwide value of 57,600 mBq m-2 h-1 as set by the United Nations Scientific Committee on the Effects of Atomic Radiation. It was concluded that the soil from the province does not pose any radiological health hazard to the general public.

A study on the radon removal performance of low background activated carbon

Radon and radon daughters pose significant backgrounds to rare-event searching experiments. Activated carbon, which has very strong adsorption capacity for radon, can be used for radon removal and radon enrichment. The internal 226Ra concentration ultimately limits its radon enrichment ability. In order to measure the intrinsic background and study the radon adsorption capability of Saratech activated carbon at various temperatures, a radon-emanation measurement system with a high-sensitivity radon detector and an adsorption-performance research-system have been developed. In this paper, a 0.71 mBq/m3 high-sensitivity radon detector and measurement details of the radon-adsorption capability of Saratech activated carbon at low temperature will be presented.

Pilot groundwater radon mapping and the assessment of health risk from heavy metals in drinking water of southwest, Nigeria

Radon and heavy metals are sources of groundwater pollution and are identified as potential carcinogens. Southwest Nigeria's populace mostly relies on groundwater source for drinking. This study aims to map radon distribution in groundwater of southwest Nigeria and to determine the health risk of radon and heavy metal in drinking water. Radon concentrations of 145 groundwater samples were measured using RAD7 electronic radon detector and heavy metal concentrations of 52 groundwater samples were measured using atomic absorption spectrophotometer. Radon concentration distributions were delineated using geographical information system. Radon concentration of water samples ranges between 1.6 Bq l−1 and 271 Bq l−1 with an average value of 35.9 ± 38.4 Bq l−1. The average groundwater radon concentration is higher than US-EPA recommended level of 11.1 Bq l−1 but lower than the WHO recommended limit of 100 Bq l−1. The estimated average annual effective radiation doses to infants, children, and adults are 29 μSvy−1, 41 μSvy−1 and 92 μSvy−1 respectively. The radon distribution map of the study area reveals regions of high, medium, and low groundwater radon concentrations. The average concentration values of heavy metals in groundwater samples are of the order Mn > Zn > Pb > Cu > Cr > Ni > Cd. 84% of groundwater exhibits good to excellent quality in terms of heavy metal pollution. However, about 16% of the samples which lie in the sedimentary regions of Ogun and Lagos States exhibit poor to very poor quality. Overall, ingestion of groundwater in the study area may not pose a serious health hazards from radon ingestion and heavy metal toxicity.

Comparison of Indoor Radon Reduction Effects Based on Apartment Housing Ventilation Methods

A lack of ventilation in multi-unit dwellings can affect human health adversely owing to accumulated radon gases; therefore, developing immediate and effective methods to reduce radon gas in indoor living environments is urgently needed. Therefore, this study conducted a basic research study to develop ventilation guidelines for radon through assessments of various ventilation strategies on indoor radon concentration in multiple-unit dwellings, a typical residential type in Korea. Radon measurement was conducted in November 2020 using RAD 7 Radon Detector (Durridge Co., Billerica, MA, USA) for living rooms and rooms of an apartment located in Uijeongbu, Gyeonggi-do, Korea. The radon reduction effect according to the ventilation conditions per hour was compared and evaluated by performing seven natural ventilation scenarios through opening and closing windows leading to the outside and three types of mechanical ventilation with high, middle, and low operating intensity. The concentration ratio (Cr) was estimated to present the indoor radon increase/decrease ratio. Among the natural ventilation scenarios, Case 3 had the highest radon reduction rate in the living room and Case 1 in the room, and Case 2 using natural ventilation equipment showed the lowest reduction rate in both the room and the living room. When ventilated by mechanical ventilation conditions, the radon reduction rate (Pr) was 70% or less under all conditions. Under the natural ventilation measurement condition, when every doors and windows was opened, it showed an effective ventilation in a short time. With high mechanical ventilation, the radon reduction effect in a relatively large space was better. Additionally, with middle and low mechanical ventilation, the reduction effect seems to be good in a relatively narrow space.

Importance of radon assessment in indoor Environment-a review

Radon is odourless, colourless indoor air pollutant from the radiation source of uranium. The source of radon in indoor are walls, floor and ceiling. Importance of radon detection at buildings are rare as it cannot be suspected until faced with an health issues. Concentration of radon in indoor environment depends on various factors. Lund disorders are the most commonly reported issue with radon exposure. This paper concentrates on the sources, factors influencing the radon dispersion and the health issues rise up with high radon exposure.

INDOOR RADON-222 CONCENTRATION MEASUREMENTS AT FACULTY OF EDUCATION, YAFEA, ADEN UNIVERSITY, YEMEN, USING CR-39 NUCLEAR TRACK DETECTOR

In this study, the activity concentration of indoor radon-222, annual effective dose, exhalation rate of radon, and relative risk of lung cancer are reported for different indoor buildings (students' dorms, teachers' dorms, offices, laboratories, library, lecture halls, and materials store) in Faculty of Education, Yafea, Aden University, Yemen. Sealed-can technique based on CR-39 nuclear tracks detector was distributed to radon gas survey. Twenty six radon detectors were mounted in seven buildings. The Radon measurements were performed for 90 days between December 2020 and March 2021. The results showed that the radon concentration ranges from 23,18 Bq m-3 to 66.49 Bq m-3 with an average value 35.86 Bq m-3, the annual effective dose ranges from 0.6 mSv y-1 to 1.639 mSv y-1 with an average value 0.979 mSv y-1, the exhalation rate ranges from 10.03 m Bq m-2 h-1 to 28.50 mBq m-2 h-1 with an average value 15.68 mBq m-2 h-1 and relative risk of lung cancer ranges from 1.02 to 1.06 with an average value 1.03. A strong correlation coefficient has been observed between radon concentration and radon exhalation rate. All of the values revealed in the study were of nominal state (that is less than allowed global values) and thus have no risk for the population living in these buildings.

Statistical Characterization of Damage of Different Surface P-Wave Velocity Sets under Dynamic Load and Study on Overall Radon Detection Consistency

Abstract On the basis of reviewing the existing research status of cumulative damage of the rock mass and summarizing the existing engineering application fields of radon, this paper attempts to apply radon detection technology to the research field of rock damage mechanics so as to monitor the evolution process of cumulative damage of the rock mass. Based on the above research purposes, a test device for detecting cumulative damage of radioactive rocks by surface radon gas was designed, and the test results were obtained by integrating the system to implement the test scheme. Due to the limitation of the nonmetallic ultrasonic detector, a single blasting damage value of 25 detection points appears after a single blasting measurement, which is a surface longitudinal wave velocity characterization damage set, while the surface radon exhalation rate in the subsequent analysis process is an overall characterization value; that is, the existence of damage directly affects the whole body radon exhalation rate of the test block, and the data dimensions of the two are different. In order to solve this problem, we try to introduce three data evaluation methods, the average weighting method, grey prediction method, and K-means clustering algorithm, and compare the feasibility of these three methods. It is proved that there is a certain linear relationship between the radon exhalation rate and the cumulative damage, which further verifies the feasibility of using radon to detect cumulative damage. The results show that the cumulative damage of loaded radioactive rock test blocks can be reflected by surface radon detection technology, and finally, the correlation between the cumulative damage characteristics and the continuous change of the body radon exhalation rate is obtained. Based on the correlation, the body radon exhalation rate is introduced into the field of fractured rock mass damage characterization, which is mutually improved with common monitoring methods such as acoustic emission and microseismic monitoring, supplementing and enriching the means of rock mass damage evolution characterization, providing a theoretical basis for finely describing the whole process of fracture closure and initiation, and finally accurately ensuring the stability of surrounding rock under the action of deep underground engineering excavation disturbance.