Radon concentrations in high background radiation areas in the south are higher than those of others in China, especially 220 Rn concentration is significantly high. Therefore, measurements of 222 Rn and...Radon concentrations in high background radiation areas in the south are higher than those of others in China, especially 220 Rn concentration is significantly high. Therefore, measurements of 222 Rn and 220 Rn concentrations should be carried out there. This paper introduces a large size collector of radon progeny and its applications. The collector is a sheet of polyvinyl chloride fiber with electrostatics of (-500 V)-(-700 V). Its size (60 mm in diameter) is larger than those of others (26 mm in diameter) that work with the same principle. The collector is more effective to adsorb radon progeny than most of others. The equipment of ZnS(Ag) Scintillation Counting System is available for large size collectors to detect radon progeny. Therefore, its sensitivity of measurement is higher than that of others. According to the different half lives of radon progeny, and based on both theory and experiments, a formula for discrimination and calculation of 222 Rn and 220 Rn concentrations is deduced. The 222 Rn and 220 Rn concentrations were surveyed with electrostatic collectors of radon progeny on the campus of commercial school and some other areas in Hainan, southern China. Neither 222 Rn nor 220 Rn concentration was found significantly high. However, several faults underground were delineated. The collector is also used to study radon transportation. Results indicate that radon changes regularly with date when it has transported for a certain distance. Velocities of radon migration in the four media are quite different. Radon migrates more quickly in vertical tube than in the horizontal tube.展开更多
Radon(Rn)is a naturally occurring radioactive inert gas in nature,and^(222)Rn has been routinely used as a powerful tracer in various aquatic environmental research on timescales of hours to days,such as submarine gro...Radon(Rn)is a naturally occurring radioactive inert gas in nature,and^(222)Rn has been routinely used as a powerful tracer in various aquatic environmental research on timescales of hours to days,such as submarine groundwater discharge.Here we developed a new approach to measure^(222)Rn in discrete water samples with a wide range of^(222)Rn concentrations using a Pulsed Ionization Chamber(PIC)Radon Detector.The sensitivity of the new PIC system is evaluated at 6.06 counts per minute for 1 Bq/L when a 500 mL water sample volume is used.A robust logarithmic correlation between sample volumes,ranging from 250 mL to 5000 mL,and system sensitivity obtained in this study strongly suggests that this approach is suitable for measuring radon concentration levels in various natural waters.Compared to the currently available methods for measuring radon in grab samples,the PIC system is cheaper,easier to operate and does not require extra accessories(e.g.,drying tubes etc.)to maintain stable measurements throughout the counting procedure.展开更多
Throughout the United States, laboratories use different sampling methods (“Direct Fill” vs. “Submerged Bottle” methods), sample preparations (“Simultaneous Drawing” vs. “Separate Drawing”), scintillators (“M...Throughout the United States, laboratories use different sampling methods (“Direct Fill” vs. “Submerged Bottle” methods), sample preparations (“Simultaneous Drawing” vs. “Separate Drawing”), scintillators (“Mineral Oil” vs. “Opti-Fluor”), volume of water plus scintillator in the cocktail (“8 mL plus 8 mL” vs. “10 mL plus 10 mL”), and liquid scintillation counting assays (“Full Spectrum: 0 - 2000 keV” vs. “Region of Interest: 130 - 700 keV”) for analyzing radon (222Rn) in water. We compared these and few other variables on the recovery of radon from two “Proficiency Test (PT)” samples and four “Household Well Water” samples from Georgia. The “130 - 700 keV” assay had significantly higher radon recovery than the “0 - 2000 keV” assay. The “Direct Fill” sampling produced significantly lower radon recovery than the “Submerged Bottle” sampling. “Simultaneous Drawing” of both scintillator and water sample yielded higher radon recovery than “Separate Drawing”. Air bubble in the samples resulted in significant loss of radon gas;and such loss became greater as the air bubble was larger. A “10 mL scintillator + 10 sample” combination appeared better than “8 mL scintillator + 8 mL sample”. Mixing scintillator and sample in the laboratory, when compared with doing it on-site, was found superior for better results and practicality of testing radon in private well waters. “Mineral Oil” scintillator provided higher radon activity than “Opti-Fluor”. However, in 10 consecutive measurements of the two proficiency test (PT) samples at 60 days interval (i.e., with full ingrowing), “Mineral Oil” overestimated the radon activity compared to the predicted/assigned value in most cases, whereas “Opti-Fluor” invariably produced results close to the predicted/assigned value. There were noticeable temporal variations in both radon and uranium concentrations in the study wells;nevertheless, uranium and radon concentrations had good positive correlation. Despite this, the use of uranium concentration over 30 ppb (the MCL of uranium in drinking water) as a trigger for recommending test for radon in well water remains questionable because there may be the safe level of uranium but unsafe level of radon in a well and vice versa.展开更多
This work presents the results of the Radon (220Rn and 222Rn) measurements made with 486 chips of CR-39 (Allyl Dyglicol Poly Carbonate) MASL? bared detectors, in a reticular mode distribution, inside of a cellar with ...This work presents the results of the Radon (220Rn and 222Rn) measurements made with 486 chips of CR-39 (Allyl Dyglicol Poly Carbonate) MASL? bared detectors, in a reticular mode distribution, inside of a cellar with average indoor radon concentration 862 ± 49 Bq/m3. The exposure time was 3 months, in microclimate condition of constant temperature, humidity, barometric pressure and no airflow. After these 3 months, all the detectors were chemically etched in KOH 6.25 M solution at 60°C ± 1°C for 18 hours, following a very well established protocol for indoor radon survey by the Dosimetry Applications Laboratory of the Physics Institute of the National Autonomous University of Mexico, and later read automatically by CADIS (Counting Automatically Digital Image System). The results show that each one of the nine measured planes is not homogeneous presenting important differences of indoor radon concentration values. Specifically, the Radon (220Rn and 222Rn) concentration levels vary for each measured point within the cellar. It is a very important observation to consider for the calculation of dose and radiological risk.展开更多
Abundant data have been gathered through measurements of radon gas emission in the soil on several major active faults,such as San Andreas and Calaveras,in California,U.S.A..They show radon emissions and their spatial...Abundant data have been gathered through measurements of radon gas emission in the soil on several major active faults,such as San Andreas and Calaveras,in California,U.S.A..They show radon emissions and their spatial variations at the unlocked,locked,and creeping sections of faults with different tectonic movements.The characteristics of these variations and the role of fault gases in the research on earthquake prediction are discussed in this paper.展开更多
A numerical has been developed for the transport of radon gas in the soil-rocks of Afrahotsprings, southern of Jordan using a one-dimensional model diffusion formula. Model Result shows a consistent relation between d...A numerical has been developed for the transport of radon gas in the soil-rocks of Afrahotsprings, southern of Jordan using a one-dimensional model diffusion formula. Model Result shows a consistent relation between distance from radiation source and radon concentration. Data model output were in the range of data collected from previous studies.展开更多
The concentration of Radon in mines varies tremendously according to the country rock, type of mineralization and area. Ventilation is also an important factor. The absence of ventilation in mines tends to allow a hig...The concentration of Radon in mines varies tremendously according to the country rock, type of mineralization and area. Ventilation is also an important factor. The absence of ventilation in mines tends to allow a higher concentration of Radon to build up. This is very dangerous for the miners work inside. In this present work, the radon gas concentration is practically measured in closed uranium prospect mine located at Gabal (G.) Gattar. CR-39 solid state nuclear track detector technique is used. It is found that the radon concentration is around 80 kBq m-3 and an effective ventilation rates should be applied if there will be further works in the future.展开更多
基金funded by the Basic Research and Strategic Reserve Technology Research Fund Project of CNPC (2019D-500803)the national oil and gas project (2016zx05007-006)。
文摘Radon concentrations in high background radiation areas in the south are higher than those of others in China, especially 220 Rn concentration is significantly high. Therefore, measurements of 222 Rn and 220 Rn concentrations should be carried out there. This paper introduces a large size collector of radon progeny and its applications. The collector is a sheet of polyvinyl chloride fiber with electrostatics of (-500 V)-(-700 V). Its size (60 mm in diameter) is larger than those of others (26 mm in diameter) that work with the same principle. The collector is more effective to adsorb radon progeny than most of others. The equipment of ZnS(Ag) Scintillation Counting System is available for large size collectors to detect radon progeny. Therefore, its sensitivity of measurement is higher than that of others. According to the different half lives of radon progeny, and based on both theory and experiments, a formula for discrimination and calculation of 222 Rn and 220 Rn concentrations is deduced. The 222 Rn and 220 Rn concentrations were surveyed with electrostatic collectors of radon progeny on the campus of commercial school and some other areas in Hainan, southern China. Neither 222 Rn nor 220 Rn concentration was found significantly high. However, several faults underground were delineated. The collector is also used to study radon transportation. Results indicate that radon changes regularly with date when it has transported for a certain distance. Velocities of radon migration in the four media are quite different. Radon migrates more quickly in vertical tube than in the horizontal tube.
基金The National Natural Science Foundation of China under contract Nos 42130410,41876075 and U1906210the Fundamental Research Funds for the Central Universities under contract No.201962003.
文摘Radon(Rn)is a naturally occurring radioactive inert gas in nature,and^(222)Rn has been routinely used as a powerful tracer in various aquatic environmental research on timescales of hours to days,such as submarine groundwater discharge.Here we developed a new approach to measure^(222)Rn in discrete water samples with a wide range of^(222)Rn concentrations using a Pulsed Ionization Chamber(PIC)Radon Detector.The sensitivity of the new PIC system is evaluated at 6.06 counts per minute for 1 Bq/L when a 500 mL water sample volume is used.A robust logarithmic correlation between sample volumes,ranging from 250 mL to 5000 mL,and system sensitivity obtained in this study strongly suggests that this approach is suitable for measuring radon concentration levels in various natural waters.Compared to the currently available methods for measuring radon in grab samples,the PIC system is cheaper,easier to operate and does not require extra accessories(e.g.,drying tubes etc.)to maintain stable measurements throughout the counting procedure.
文摘Throughout the United States, laboratories use different sampling methods (“Direct Fill” vs. “Submerged Bottle” methods), sample preparations (“Simultaneous Drawing” vs. “Separate Drawing”), scintillators (“Mineral Oil” vs. “Opti-Fluor”), volume of water plus scintillator in the cocktail (“8 mL plus 8 mL” vs. “10 mL plus 10 mL”), and liquid scintillation counting assays (“Full Spectrum: 0 - 2000 keV” vs. “Region of Interest: 130 - 700 keV”) for analyzing radon (222Rn) in water. We compared these and few other variables on the recovery of radon from two “Proficiency Test (PT)” samples and four “Household Well Water” samples from Georgia. The “130 - 700 keV” assay had significantly higher radon recovery than the “0 - 2000 keV” assay. The “Direct Fill” sampling produced significantly lower radon recovery than the “Submerged Bottle” sampling. “Simultaneous Drawing” of both scintillator and water sample yielded higher radon recovery than “Separate Drawing”. Air bubble in the samples resulted in significant loss of radon gas;and such loss became greater as the air bubble was larger. A “10 mL scintillator + 10 sample” combination appeared better than “8 mL scintillator + 8 mL sample”. Mixing scintillator and sample in the laboratory, when compared with doing it on-site, was found superior for better results and practicality of testing radon in private well waters. “Mineral Oil” scintillator provided higher radon activity than “Opti-Fluor”. However, in 10 consecutive measurements of the two proficiency test (PT) samples at 60 days interval (i.e., with full ingrowing), “Mineral Oil” overestimated the radon activity compared to the predicted/assigned value in most cases, whereas “Opti-Fluor” invariably produced results close to the predicted/assigned value. There were noticeable temporal variations in both radon and uranium concentrations in the study wells;nevertheless, uranium and radon concentrations had good positive correlation. Despite this, the use of uranium concentration over 30 ppb (the MCL of uranium in drinking water) as a trigger for recommending test for radon in well water remains questionable because there may be the safe level of uranium but unsafe level of radon in a well and vice versa.
文摘This work presents the results of the Radon (220Rn and 222Rn) measurements made with 486 chips of CR-39 (Allyl Dyglicol Poly Carbonate) MASL? bared detectors, in a reticular mode distribution, inside of a cellar with average indoor radon concentration 862 ± 49 Bq/m3. The exposure time was 3 months, in microclimate condition of constant temperature, humidity, barometric pressure and no airflow. After these 3 months, all the detectors were chemically etched in KOH 6.25 M solution at 60°C ± 1°C for 18 hours, following a very well established protocol for indoor radon survey by the Dosimetry Applications Laboratory of the Physics Institute of the National Autonomous University of Mexico, and later read automatically by CADIS (Counting Automatically Digital Image System). The results show that each one of the nine measured planes is not homogeneous presenting important differences of indoor radon concentration values. Specifically, the Radon (220Rn and 222Rn) concentration levels vary for each measured point within the cellar. It is a very important observation to consider for the calculation of dose and radiological risk.
文摘Abundant data have been gathered through measurements of radon gas emission in the soil on several major active faults,such as San Andreas and Calaveras,in California,U.S.A..They show radon emissions and their spatial variations at the unlocked,locked,and creeping sections of faults with different tectonic movements.The characteristics of these variations and the role of fault gases in the research on earthquake prediction are discussed in this paper.
文摘A numerical has been developed for the transport of radon gas in the soil-rocks of Afrahotsprings, southern of Jordan using a one-dimensional model diffusion formula. Model Result shows a consistent relation between distance from radiation source and radon concentration. Data model output were in the range of data collected from previous studies.
文摘The concentration of Radon in mines varies tremendously according to the country rock, type of mineralization and area. Ventilation is also an important factor. The absence of ventilation in mines tends to allow a higher concentration of Radon to build up. This is very dangerous for the miners work inside. In this present work, the radon gas concentration is practically measured in closed uranium prospect mine located at Gabal (G.) Gattar. CR-39 solid state nuclear track detector technique is used. It is found that the radon concentration is around 80 kBq m-3 and an effective ventilation rates should be applied if there will be further works in the future.
