Simultaneous indoor measurements of radon, thoron and equilibrium equivalent con centrations, by three different continuous radon monitors in real ambient conditions, were performed and compared ...during two weeks period. Radon concentrations varied from 153 Bqm?3 to 870 Bqm?3 with variations of thoron concentrations in the range (2.17-219) Bqm?3. Obtained arithmetic means of equilibrium equivalent radon and thoron concentrations were (130 ? 50) Bqm?3 and (23 ? 18) Bqm?3, respectively. The inter-comparison of active radon de vices was focused on consistency of results between them selves and the influence of environmental conditions on the behavior of each detector system. The obtained statistically significant correlation between the results of used monitors, validates them for application in radon diagnostic measurements as the first step in radon remediation and dose assessment.
Exploration of possible anomalies in the decay of different radionuclides is an active research area in the fields of astrophysics and nuclear physics. The most significant changes in decay rates can ...be expected for β−, β+ or electron capture decay nuclides, due to the proposed influence of the solar neutrino flux by some research groups. In this work, the nuclear decay rate of β+ decay of N22a was investigated during the time interval of ~33 days. For this purpose, a coincidence system based on a planar high purity germanium detector and a plastic scintillation detector was designed and used for the acquisition of experimental N22a coincidence spectrum. The corresponding experimental conditions: temperature, atmospheric pressure, and relative humidity, which may affect the measurement system, were monitored. In addition, Monte-Carlo simulations of this system were performed in order to obtain the N22a simulated coincidence spectrum. The time-dependent coincidence spectra in 0.5 h bins were collected by the multiparameter MPA-3 system. The fluctuations in the decay rate (i.e. possible variations of the decay constant) were analyzed by Fourier and Lomb-Scargle algorithms. No significant evidence for periodic behavior in decay rate or aperiodic anomalies was found during the acquisition period.
•A search for possible fluctuations of 22Na decay rate was conducted.•The coincidence system based on HPGe and plastic scintillation detectors was designed.•Monte-Carlo simulations were performed and compared with experimental results.•Fourier and Lomb-Scargle analyses were applied.•No significant periodicities or aperiodic anomalies were found in the data set.
There is a dilemma whether the Chernobyl accident is the main source of this anthropogenic radionuclide in the region of Vojvodina, Northern Province of Serbia. The difference compared to the other ...dominant source of radiocaesium in the environment, the nuclear weapon tests, is lying in the local character of contamination due to accidents, which implies it’s highly dependent on meteorological parameters, such as precipitation and wind in the area at that time. According to published data, the average value of surface contamination by radiocaesium on the territory of the former Yugoslavia after the Chernobyl accident was several times higher than the estimated contamination by nuclear testing (1945–1963). The main aim of this research is to explore possible correlations of the spatial distribution of precipitation from April 1986 to December 1987 with the deposition of radiocaesium in the surface soil to justify this claim in the absence of data on caesium deposition before the Chernobyl accident for the Vojvodina region. The database of 137Cs content in Vojvodina soil and precipitation for this region during the timeframe of interest were used. From a total of 245 precipitation stations in Vojvodina, 164 to 244 precipitation stations were selected for analysis in conditionals from different time scale aspects and data validation. The best correlation between amounts of total precipitation and 137Cs content in surface soil obtained for two rainy periods 2nd-5th and 7th-21st May 1986. Further cluster analysis separated four different regions according to 137Cs deposition and precipitation for the mentioned rainy period which could be applied in the field of soil erosion assessment on the local and regional level.
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•Vojvodina 137Cs fallout Chernobyl accident or nuclear weapon testing originated.•Correlations of precipitation in 1986/87 and 137Cs deposition densities.•The periods 2nd to 5th and 7th to May 21, 1986 best correlated with 137Cs in soil.•Four regions in Vojvodina were derived by cluster analysis of two sets of data.•The results were validated by reconstruction of the winds aloft directions.
Most studies focused on thoron have shown that indoor thoron originates mainly from building materials and that thoron concentrations exponentially decrease with a distance from a wall surface. On ...the contrary, due to longer half-lives of thoron progenies, 212Pb and 212Bi, which are mainly responsible for the bronchial dose, it is expected that their spatial distribution is homogeneous. Therefore, direct measurements of thoron progeny concentrations or direct thoron measurement and determination of thoron equilibrium factor are necessary for accurate dose assessment. In this paper, we have optimized and validated a reliable and inexpensive method for direct measurement of thoron progenies concentrations based on an air filtration followed by gamma spectrometry measurements. With simultaneous measurements of indoor thoron by the RAD7 active device, the equilibrium factor for thoron in 15 different investigated dwellings was estimated. Obtained results for the equilibrium equivalent thoron concentrations in the range from 0.277 Bq/m3 to 11.34 Bq/m3 and thoron equilibrium factor in the range from 0.0047 to 0.098 with arithmetic mean value of 0.034 are in good agreement with already published results.
•A method for direct determination of thoron progenies was proposed and optimized.•Obtained thoron equilibrium factors are in good agreement with the UNSCEAR value.•Estimated dose from thoron progenies are comparable to radon inhalation dose.
There is a dilemma whether the Chernobyl accident is the main source of this anthropogenic radionuclide in the region of Vojvodina, Northern Province of Serbia. The difference compared to the other ...dominant source of radiocaesium in the environment, the nuclear weapon tests, is lying in the local character of contamination due to accidents, which implies it's highly dependent on meteorological parameters, such as precipitation and wind in the area at that time. According to published data, the average value of surface contamination by radiocaesium on the territory of the former Yugoslavia after the Chernobyl accident was several times higher than the estimated contamination by nuclear testing (1945-1963). The main aim of this research is to explore possible correlations of the spatial distribution of precipitation from April 1986 to December 1987 with the deposition of radiocaesium in the surface soil to justify this claim in the absence of data on caesium deposition before the Chernobyl accident for the Vojvodina region. The database of
Cs content in Vojvodina soil and precipitation for this region during the timeframe of interest were used. From a total of 245 precipitation stations in Vojvodina, 164 to 244 precipitation stations were selected for analysis in conditionals from different time scale aspects and data validation. The best correlation between amounts of total precipitation and
Cs content in surface soil obtained for two rainy periods 2nd-5th and 7th-21st May 1986. Further cluster analysis separated four different regions according to
Cs deposition and precipitation for the mentioned rainy period which could be applied in the field of soil erosion assessment on the local and regional level.
Isotopes of hydrogen (
3
H,
2
H) and oxygen (
18
O) are perfect candidates for groundwater tracers. A survey of isotopic composition of 34 groundwater samples and one Lake from Vojvodina region ...(Serbia) is presented here. Tritium activity concentration and stable isotope composition (δ
2
H, δ
18
O), as well as deuterium excess, were determined. The groundwater samples lie on the groundwater regression line. Minor deviations and a few lower deuterium excess values indicate waters recharged in a different climate regime and subjected to evaporation, respectively. According to the obtained results, most of the analyzed groundwater can be characterized as modern waters, recharged mostly from precipitation.
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