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Radon observation is an important measurement item of seismic precursor network observation. The radon detector calibration is a key technical link for ensuring radon observation accuracy. At present, the radon detector calibration in seismic systems in China is faced with a series of bottleneck problems, such as aging and scrap, acquisition difficulties, high supervision costs, and transportation limitations of radon sources. As a result, a large number of radon detectors cannot be accurately calibrated regularly, seriously affecting the accuracy and reliability of radon observation data in China. To solve this problem, a new calibration method for radon detectors was established. The advantage of this method is that the dangerous radioactive substance, i.e., the radon source, can be avoided, but only “standard instruments” and water samples with certain dissolved radon concentrations can be used to realize radon detector calibration. This method avoids the risk of radioactive leakage and solves the current widespread difficulties and bottleneck of radon detector calibration in seismic systems in China. The comparison experiment with the traditional calibration method shows that the error of the calibration coefficient obtained by the new method is less than 5% compared with that by the traditional method, which meets the requirements of seismic observation systems, confirming the reliability of the new method. This new method can completely replace the traditional calibration method of using a radon source in seismic systems. [ABSTRACT FROM AUTHOR]

Radon, a proven highly carcinogenic gas, has raised serious concerns, necessitating its measurement in residential areas. In the coastal city of Sharjah, United Arab Emirates (UAE), the first indoor radon concentration measurements were conducted. Following the Environmental Protection Agency (EPA) protocol, active radon detectors were employed in the living rooms of houses across the south-east region of the city. Measurements revealed that, the mean values during winter are of (39.6 ± 12.2) Bq/m3 (floor 1) and (35.7 ± 9.8) Bq/m3 (floor 2), while in summer, levels were slightly higher on floor 1 (55.8 ± 10.1) Bq/m3 compared to floor 2 (47.8 ± 12.6) Bq/m3. Ground floor analysis showed mean values of (57.0 ± 12) Bq/m3 in summer and (49.0 ± 16) Bq/m3 in winter. Higher summer levels were linked to climatic conditions and increased time spent indoors. The excess lifetime cancer risk for ground floor radon was estimated as 0.341% over 25 years. Annual dose equivalent was calculated using International Commission on Radiological Protection (ICRP) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) models. The calculated results were found to range from 1.7 to 3.0 millisieverts (mSv), which is within permissible limits.

Usually, radon detector must be calibrated every year, commonly used solid radon source calibration method and radon chamber calibration method. The former has the problems of radon source device aging, complex operation and radioactive substances vulnerable to transport control. The latter has problems such as calibration time principal and inability to achieve on-site calibration. Based on the above facts, this paper proposes an experimental method for the calibration of radon measuring instrument using uranium waste rock, which is used to realize the field calibration of seismic radon measuring instrument. The results show that the radon concentration control method has high accuracy and stability, and the relative error between the output gas radon concentration and the preset target is 1%. The comparison between the calibration experiment of uranium mine waste rock and the calibration experiment of standard radon chamber shows that the calibration values of the calibration coefficient of the two are in good agreement, the relative error is only 1.14%, and the normalized error En is only 0.135 6, which is within the expected range. It can provide theoretical support for the subsequent development of portable radon detector calibration device.

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Evaluating the radon emissions from building structures to determine optimal strategies for either preventing radon infiltration into buildings or decreasing its concentration in occupied areas is essential. This research presents a study of different methodologies for determining the radon exhalation rate in three samples of granite: two techniques based on passive detectors (Electret Ion Chamber (EIC) and Solid State Nuclear Track Detectors (SSNTD)) and one technique based on the use of a continuous radon detector. The operating principle of the three methodologies is based on the accumulation of radon inside an experimental container, hermetically sealed. Passive detectors offer the concentration measurement, integrated over time, while the continuous detector monitors the increase in concentration hour by hour. In this last case, three mathematical models have been applied to adjust the experimental results. According to a previous radiological characterization of the building material samples, those exceeding the legal limit of the radioactive activity index (I = 1) have been analyzed: Rose Porriño granite, Blue Vizag granite and Julia Cream granite. The obtained results indicate that the five methodologies used present radon exhalation rate values within a consistent range for each sample. Therefore, the protocols detailed in this work could be used interchangeably to calculate the radon gas exhalation rates in building materials, providing flexibility in selecting the most suitable method depending specific experimental requirements or constraints. • Radon exhalation rate in building materials has been determined. • Developed different methodologies to measure radon exhalation rate. • Passive and continuous detectors procedures have been validated through experimental results. • Reduction of sampling times compared to ISO 11665-9 procedure. [ABSTRACT FROM AUTHOR]

In recent years, BG2015R radon detector has been applied to radon observation in seismic industry as a new type of instruments. However, there are relatively few seismic stations using it for radon concentration observation as a formal instrument. The instrument was installed in Ningde seismic station in January 2019 and officially put into operation in January 2020 after trial operation. In the process of observation, certain understandings of the performance and operating characteristics of the instrument have been obtained. In this paper, two sets of radon measuring instrument systems, SD-3A and BG2015R, were carried out synchronous and comparative observation in series network in Ningde No.1 observation well, and the observation data and instrument operation were compared and analyzed, providing reference for other seismic stations in instrument selection, data analysis, system operation and maintenance.

Using Monte Carlo (with Geant4) and COMSOL simulations, the authors have defined a useful tool to reproduce the alpha spectroscopy of 222Rn, 220Rn and their ionized daughters by measurement systems based on electrostatic collection on a silicon detector, inside a metallic chamber. Several applications have been performed: (i) simulating commercial devices worldwide used, and comparing them with experimental theoretical results; (ii) studying of realization of new measurement systems through investigation of the detection efficiency versus different chamber geometries. New considerations and steps forward have been drawn. The present work is a novelty in the literature concerning this research framework. [ABSTRACT FROM AUTHOR]

Using Monte Carlo (with Geant4) and COMSOL simulations, the authors have defined a useful tool to reproduce the alpha spectroscopy of 222Rn, 220Rn and their ionized daughters by measurement systems based on electrostatic collection on a silicon detector, inside a metallic chamber. Several applications have been performed: (i) simulating commercial devices worldwide used, and comparing them with experimental theoretical results; (ii) studying of realization of new measurement systems through investigation of the detection efficiency versus different chamber geometries. New considerations and steps forward have been drawn. The present work is a novelty in the literature concerning this research framework.

Background: From the health physics perspective, radon gas is one of the most dangerous gases in residential and business environments. According to the WHO (World Health Organization), radon gas is considered the second cause of lung cancer in societies after smoking. Methods: In this study, the environmental radon gas has been measured using a built radon gas detector on a specific preamplifier circuit and then the perceived results were compared with an Alpha-Guard detector. Specific activity and output ratio on radon concentration in air were measured on three different floors of a residential building covered by different materials. Results: The results showed a good correlation between the outputs and data gathered by the Alpha-Guard. In underground covered by plaster and cement, the detector responses showed approximately double amounts in comparison with the ground floor. The different covered places revealed dissimilar responses, so that the screened granite had greater amounts by 347 ± 37 Bq/m3. Besides, the minimum response was revealed on the first floor using Alpha-Guard by 47 ± 6 Bq/m3. Results confirmed that on each floor, which has a good ventilation system, the exposure due to the radon isotopes can be immensely reduced. Conclusions: This system can also be used to measure the radon concentration changes in the environment and groundwater. [ABSTRACT FROM AUTHOR]

Temporal variations of radon concentration in soil before the earthquake are known as an earthquake precursor. For using of radon as an earthquake precursor, it is necessary to constantly monitor radon concentration variations in a relatively wide range in the vicinity of a fault which is virtually impossible for radon detectors that already exist. This paper proposes a new method for continuous measurement of radon concentration variations in a wide range, using optical fiber as radon detector. For this purpose, an experimental system consisting of radon source, optical-fiber holding chamber, radon gas detector, optical laser source, and optical power meter have been arranged to with the aim to create different concentrations of radon gas in the vicinity of the optical fiber; the attenuation which creates on optical fiber is subsequently measured. As a result, the average of the attenuation is 0.004 μw per each meter per Bq/l since the fault's length is more than ten kilometers; sensitivity of the measurement can be improved many times over. [ABSTRACT FROM AUTHOR]

As an element of the joint IAEA-EPA International Radon Metrology Evaluation Program, a climatic test of long-term integrating radon detectors was conducted at the U.S. EPA Radiation and Indoor EnvironmentsNational Laboratory. The objective of this study was to test the performance of commonly used commercially available long-term 222Rn detector systems under extreme climatological conditions usingfiltered polycarbonate CR-39 plastic analyzed by the manufacturer using the track-etch method, unfiltered LR-115 film analyzed by the manufacturer, and TeflonTM based electrets analyzed in the field by EPA using the manufacturer's equipment. The EPA environmental radon chambers were used to expose detectors to extreme cold and dry (less than 4.0 deg. C air temperature and 25% relative humidity) andhot and humid (greater than 35 deg. C air temperature and 85% relative humidity) climatic conditions. During phase I detectors were exposed to low temperatures and low humidities, and during phase II detectors were exposed to high temperatures and high humidities. Typical indoor equilibrium fractions (near 50%) and radon concentrations of about 150 Bq m-3 were maintained for each phase, which lasted 90 d. The results indicated that the optimal detector for extreme climatic conditions is dependent on the relative importance of bias and precision. Overall, however, the filtered track-etch type detector produced the most reliable results under the extreme conditions. [ABSTRACT FROM AUTHOR]

The Ardennes and Eifel region is a geologically distinct area covering parts of Germany, Belgium, France, and Luxembourg where enhanced concentrations of radon occur in some houses and other buildings. An international case-control study is being conducted to examine the role of radon in the etiology of lung cancer in this area. The radon detectors used are issued by different laboratories involving a variety of detector types and processes. A series of intercomparisons in houses was therefore conducted under similar conditions of exposure in the field. In most situations the different detectors gave similar results. Nevertheless, in some situations open and closed detectors yielded different results. Therefore, estimates of radon exposure have to be adjusted if results are to be pooled. [ABSTRACT FROM AUTHOR]