The 7 Be content was measured in aerosols (once per week) and precipitation (once per month) was monitored as part of the monitoring of the radioactivity of the atmospheric layer near the ground in Rostovon-Don in 2001-2005. Data were obtained on the correlations between the 7 Be volume activity in aerosols and the Wolf number, temperature, and amount of precipitation. The highest correlation coefficients were observed during the spring (k = 1). It was determined that the volume activity of 7 Be changes in the second half of the 23rd cycle of solar activity, i.e., the yearly average 7 Be concentration increases toward the end of the cycle. Data were obtained on the seasonal dependence of the precipitation density and the volume activity of 7 Be on the meteorological parameters (temperature, amount of precipitation).Cosmogenic 7 Be (T 1/2 = 52.3 days) forms in nuclear spallation reactions when high-energy protons (∼1 GeV) when cosmic rays interact with nitrogen nuclei in the stratosphere 14 N + p → 7 Be (up to 70-80%) and secondary neutrons with nitrogen nuclei and oxygen in the troposphere 14 N + n → 7 Be and 16 O + n → 7 Be (up to 20-30%) [1,2]. During changes in the solar activity (number of sun spots -the Wolf number W) within the 11-year solar cycle and aperiodic bursts of solar activity, the geomagnetic field changes, cosmic rays are deflected and, correspondingly, the 7 Be production rate changes [3]. A decrease of the 7 Be production rate corresponds to an increase of solar activity (increase of the Wolf number) and vice versa, i.e., there is an anticorrelation between the 7 Be content in the atmospheric air and the Wolf number with coefficient k = −0.81 according to [4] and k = −0.83 ± 0.03 according to the data in [5]. Over the 11-year solar cycle, the yearly average content at the maximum and minimum differs by approximately 45%. The 7 Be production rate also depends on the geographical coordinates of the observations station because of the effect of the Earth's magnetic field on the cosmic ray distribution.Long (more than two cycles of solar activity) systematic measurements on the global network of stations must be performed in order to determine reliably the relation between the 7 Be volume activity in the air layer at the ground and the solar activity against the background of variations of a different origin. The results of the determination of 7 Be in the atmosphere in 1974-1999 at 26 stations were analyzed in [3]. The existence of the anticorrelation indicated above, which explains about 54% of all temporal variations of the 7 Be for stations in Australia, New Zealand, and North America and only 18% of the variations for the stations in South America and Antarctica, has been proven. Long-time measurements (1987Long-time measurements ( -2003 were performed recently at temperate latitudes (40°38′) [6]. Under especially favorable conditions (regularity of measurements of the meteorological parameters, absence of any effect due to some of them, and so forth), a correlation between the 7 Be content an...
Analysis of data obtained in 1990 and 2000 on the 137 Cs contamination of the bottom of the Tsimlyanskoe reservoir near the dam has revealed the salient variations of this contamination. The global fallout enters the water in the section near the dam from side tributaries and as a result of erosion from the closest water catchment areas. The fallout due to the accident at the Chernobyl nuclear power plant is added primarily with the solid runoff from the more highly contaminated catchment basins of the Don River. It is shown that shore abrasion, flows, and removal of sediment through the water outflow area influence the distribution of the 137 Cs content over the zones and the characteristics of the variation of this distribution in time.The goal of the present work is to evaluate the characteristics of 137 Cs contamination of the bottom deposits of a low-flow reservoir for the example of the section of the Tsimlyanskoe reservoir near the dam. This section lies in the observation zone of the Volgodonsk nuclear power plant. The first assessment of the degree of 137 Cs contamination of the bottom of this reservoir was made in 1990 by obtaining samples of bottom deposits with thickness up to 15 cm [1]. As a result of the effect of runoff and inflows on the 137 Cs distribution along the bottom of the reservoir and the supposedly large effect of shore abrasion, the expeditions of 2000 made a reassessment, together with a team from the V. G. Khlopin Radium Institute, of the contamination of this section using a better method with extraction of sediments from bottom deposits (cores) and layers up to 50 cm thick (Fig. 1).The 137 Cs and 210 Pb depth distribution obtained was used to determine the average rate of sediment accumulation and for dating. The maximum in the 137 Cs depth distribution and the core date were used for the main part of the water area. The separation into zones was made taking account of the balance of the mass of the deposited material in this reservoir [2] and the general contamination of the bottom with 137 Cs in 1990 (Fig. 2) [1]. The average 137 Cs contamination density in each zone was determined by averaging the contents of this radionuclide at each sampling point, and the total activity of radionuclides in the zones was determined to take account of the area. The 137 Cs contamination density was as follows (10 4 Bq/m 2 ): 0.07 in zone I, 0.2 II, 0.4 III, 0.7 IV, 1.1 V ( Table 1).The time variation of the 137 Cs content in each zone and in the section near the dam was the same overall when the average contamination density or specific activity was used for analysis. Subsequently, to examine the 137 Cs distribution over the zones taking account of the salient features of the reservoir, the specific activity of the 15-cm layer (A 15 ), the total specific activity (A Σ ) of the water reservoir, referenced taking account of the radioactive decay to the corresponding time period, was used. The data obtained in 1990 for the section near the dam are limited with respect to the number of sampling poi...
The components of the background of a Ge(Li) detector and an ultrapure Ge detector in gamma spectrometers in passive shielding with a special design were studied in a ground-surface laboratory in 1996-2006. The measurement time varied from 45 to 240 h. The background for the detectors is due to radionuclides in the shielding material and cavities in the shielding and the detector materials themselves. Special attention is devoted to the study of the time dependence found for the background of the daughter of products of 222 Rn decay, including the 46.5 keV peak of 210 Pb.
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