No abstract available

[en] Objective of research is an estimation of accumulation of various physico-chemical forms of isotopes Am 241 and Pu 239, Pu 240 in the most widespread in Belarus sod-podzolic type of uncultivated soil, their mobile and immobile forms. Results of the estimation of some physic-chemical parameters of soil samples which have been gathered in 2006 on the territory of Palesski state radiation-ecological reserve (Belarus) are presented in the article. The results of the research could be used for prediction of plutonium and americium transfer from soil to plants. (authors)

[en] Using radioactivity measurements for ¹³¹I and ¹³⁷Cs and nuclear activation analysis (NAA) or accelerator mass spectrometry (AMS) for ¹²⁹I, ratios of ¹³¹I/¹³⁷Cs and ¹²⁹I/¹³⁷Cs have been determined in soils from Belarus. We find that the pre-Chernobyl ratio of ¹²⁹I/¹³⁷Cs in Belarus is significantly larger than expected from nuclear weapons fallout. For the Chernobyl accident, our results support the hypothesis that there was relatively little fractionation of iodine and caesium during migration and deposition of the radioactive cloud. For sites having ¹³⁷Cs >300 Bq/kg, ¹²⁹I can potentially give more reliable retroactive estimates of Chernobyl ¹³¹I deposition. However, our results suggest that ¹³⁷Cs can also give reasonably good (±50%) estimates for ¹³¹I in Belarus

No abstract available

[en] Experimental measurements shown that radioactivity of radon 222 and its daughter products in living and working spaces in towns Khojniki, Narowlya and Bragin is lower of permitted level. Building materials are main source of radon. Local authorities must decide about protection measures. (authors)

No abstract available

[en] We present a three-dimensional simulation of the ion dynamics in an electron cyclotron resonance ion source. Ion trajectories in the min-B field of the source are calculated taking ion-ion and electron-ion collisions into account. The electrons are not tracked but considered as a neutralizing background with a Maxwell-Boltzmann velocity distribution. Some applications of the code are discussed, e.g., the calculated charge-state and phase-space distributions of extracted ion beams and the ionization dynamics in the plasma.

[en] An explicit analytic expression is derived for the magnetic moment of a 2D electron gas taking into account the spin-orbit interaction in the Rashba model with T = 0. The cases of constant chemical potential and number of electrons are investigated. The magnetic field and temperature dependences of the magnetic moment are analyzed. The results are compared with the results of experimental studies of magnetization

[en] In this paper we present a simple model that we developed to reconstruct the 4-dimensional trace space distribution from the convoluted spatial images of a pepperpot emittance meter. Straightforward analysis of the images is hampered because of multiple and/or overlapping beamlets emerging from a single hole in the pepper plate. The model allows us to unambiguously assign each transmitted beamlet to its corresponding hole in the pepper plate from which it emerged. We illustrate our analysis model with the reconstruction of the 4-dimensional trace space distribution behind the analyzing magnet of a 21 keV He¹⁺ beam extracted from an electron cyclotron resonance ion source. We find in our case that the measured trace-space distributions are to a large extent determined by the ion-optical properties of the analyzing magnet. The measured trace-space distribution agree reasonably well with detailed beam transport simulations. The paper is followed by the slides of the presentation

[en] A characteristic feature of the Chernobyl NPP accident has been the intake of finely dispersed fuel particles (FP) into the biosphere. They consist from nuclear fission products and actinides with a high specific activity. The rate of radionuclides transfer (Sr, Pu, Am and others) capsulated FP is very low in comparison with condensed component of their fall out and global fall-out after nuclear weapon tests. Radionuclides transform into a mobile state and their involving into biological cycles are determined by the destruction rate of fuel particles. Distribution of FP in soils of contrast (turf, sod-podzol, sand and sandy loam) types in areas contaminated as a result of the Chernobyl accident were analysed in the present work in order to specify parameters and mechanism of vertical migration. The study was performed on the basis of the isotope uranium-236. This radionuclide is absent in nature. The levels of the soil contamination of alienation zone of Chernobyl NPP with technogenic uranium were estimated. Radiochemical extraction and purification of uranium were carried out using AV-17 anionite from hydrochloric solution and extraction with diethyl ester. The isotopic ratio of uranium was determined using mass-spectrometer HEX-ICP-QMS (Platform ICP, Micromass Ltd., Manchester, UK). Mass-spectrometer was calibrated using standard CCLU-500. On the basis of experimental data on content of uranium-236 (Chernobyl origin) and known correlation between uranium isotopes in the active core of the reactor as well as in the natural uranium the levels of the soil contamination with isotopes uranium-235 and uranium-238 additional to the natural levels were estimated. The average meaning of nuclear fuel burn up and levels of radioactive contamination of soil surface on territories, situated on different distances from Chernobyl NPP were estimated with using these values. The more than 80% of Chernobyl origin uranium are in upper 0 -10 cm soil layer, regardless of the soil type. The grade of destruction of FP on different radioactive tracks using ratio of various valence state of uranium leaching with carbonate solution was made. The results of calculation of destruction rate of FP show that there is close relation with soil properties (acidity and structure of organic materials) and properties of FP (grade of oxidation). The values of transformation constant of FP may be used for prognosis of radionuclides transformation into mobile forms and for investigation of radiological situation in Chernobyl NPP zone. (author)