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- Author or Editor: M. Chudý x
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Abstract
Near-surface air concentrations of7Be and its deposition rates were measured in the atmosphere in Bratislava from 1977 to 1994. Late spring and summer maxima were observed in the near-surface air concentrations on an annual basis. Using measured deposition rates and the calculated average tropospheric content of7Be atoms, their mean tropospheric residence time (27–48 days) was determined. An anticorrelation between the measured7Be concentration and the sunspot number with correlation factor of 0.55 was observed.
Abstract
A tritium monitor based on plastic scintillation sheets is described. The sensitive volume of the scintillation chamber is 0.95 l. The chamber with coincidence electronics has a discrimination capability and permits to detect tritium in the presence of other radionuclides and external gamma-radiation. The monitor characteristics obtained with tritiated air are presented. The monitor sensitivity for tritium in air is 5.6 cpm for each kBq·m−3. The monitoring of tritium in air and water is possible using the instrument described.
Abstract
An apparatus for natural tritium concentration measurement using an ethane-filled proportional counter with anticoincidence shielding is described. The counter characteristics and the counter calibration with internal tritium and external137Cs standards are discussed. Results of tritium analysis of Bratislava rains are presented.
Abstract
The radiation situation in Bratislava following the Chernobyl accident is discussed. Measurement results of 
- and 
-radioactivity of aerosols are presented. The evolution of the activity ratios in air for some radionuclides is discussed. Their distribution indicates different transport and deposition properties for the volatile and nonvolatile fission products. The results are compared with long-term measurements of anthropogenic radionuclides released to the atmosphere by nuclear bomb tests.
Abstract
Analyses of anthropogenic and natural gamma-ray emitters in the environment require high sensitive detector systems operating in coincidence-anticoincidence modes. Thanks to an excellent energy resolution and a high efficiency, large volume HPGe detectors have been widely used in low-level gamma-ray spectrometry. In the present paper we discuss the characteristics of single and coincidence (HPGe-NaI(Tl)) arrangements suitable for analysis of environmental samples containing cascade gamma-ray emitters (e.g., 60Co), positron emitters (e.g., 22Na) and single gamma-ray emitters (e.g., 137Cs). The detectors were placed in a large volume shields consisting of iron, lead and copper layers. The reduction of background for the single gamma-ray spectrometer is between 60 and 250, depending on the gamma-ray energy. As an improvement of the apparatus, low detection limits for analysis of 137Cs (0.3 Bq·kg−1) and 60Co (0.1 Bq·kg−1) in environmental samples, respectively, have been obtained.
Abstract
The activity concentrations of natural radionuclides in sands, gravels, cements and in different kinds of concretes were measured by 
-spectrometric methods. The222Rn exhalation rate from concretes was measured by closed chamber method and the emanation coefficient was calculated. Both used methods are described in detail and obtained results are discussed from point of view of allowed hygienic limits.
