In this paper, it is shown using one-, two-, and three-dimensional spectrometry that the excursion distributions in random sequences of counts $$k(\Delta t)$$ of alpha-particle fluxes over the time interval $$\Delta t$$ correspond to the Poisson flow model and do not have periodic components. An example of 238Pu source is used.

The Dps protein of Escherichia coli, which combines ferroxidase activity and the ability to bind DNA, is effectively used by bacteria to protect their genomes from damage. Both activities depend on the integrity of this multi-subunit protein, which has an inner cavity for iron oxides; however, the diversity of its oligomeric forms has only been studied fragmentarily. Here, we show that iron ions stabilize the dodecameric form of Dps. This was found by electrophoretic fractionation and size exclusion chromatography, which revealed several oligomers in highly purified protein samples and demonstrated their conversion to dodecamers in the presence of 1 mM Mohr’s salt. The transmission electron microscopy data contradicted the assumption that the stabilizing effect is given by the optimal core size formed in the inner cavity of Dps. The charge state of iron ions was evaluated using Mössbauer spectroscopy, which showed the presence of Fe3O4, rather than the expected Fe2O3, in the sample. Assuming that Fe2+ can form additional inter-subunit contacts, we modeled the interaction of FeO and Fe2O3 with Dps, but the binding sites with putative functionality were predicted only for Fe2O3. The question of how the dodecameric form can be stabilized by ferric oxides is discussed.

A method of elimination of silicon compounds from the anode wire of an aged proportional counter is presented. The aging of a counter with a 70%Ar + 30%CO 2 and a 60%Ar + 30%CO 2 + 10%СF 4 working mixture was stimulated by a 90 Sr β source. To accelerate the process of aging, the gas mixture flow to the counter was supplied through a pipe with RTV coated wall. As a result, the amplitude of the signal decreased 70% already at accumulated charge of Q = 0.03 C/cm. The etching of the silicon compounds on the wire surface with an 80%CF 4 + 20%CO 2 gas mixture discharge led to full recovery of the operating characteristics of detector and an increase in the lifetime. A scanning electron microscopy and X-ray spectroscopy analysis of the recovered wire surface were performed. In accordance with the results, a good quality of wire cleaning from SiO 2 compounds was obtained.

A technique to recover a gas proportional counter with an aged anode wire using a glow discharge in an 80%CF4+20%CO2 gas mixture, has been developed and tested. Studies of aging effects were carried out under sustained irradiation by an intense 90Sr β-source of straw proportional counters operated with a 60%Ar+30%CO2+10%CF4 gas mixture. Special attention was paid to the aging mechanism of the anode wires. Our experience showed that using a given gas mixture the swelling of the anode wires is a typical mode of aging that leads to degradation of the gas gain. The proposed method restores the gas gain and the signal amplitude in the damaged zone of the wire. SEM/XEM analysis confirmed that the tungsten oxide deposits have been removed.

By methods x-ray microanalysis, Rutherfod back scattering , x-ray diffraction analysis, raster electron microscopy , atomic force microscopy was researched elementary and phase composition of solid reaction products, witch appear on LiNbO3 surface at topochemical processes after plasma-chemical (PCE) and radical etching (RE)

The component redistribution during the growth of Nb and In/Nb films on single-crystal silicon has been studied by Rutherford backscattering spectroscopy and X-ray diffraction. The results indicate that magnetron sputtering of indium onto niobium films gives rise to mass transfer across the Nb/Si interface and to niobium and silicon heterodiffusion, accompanied by chemical reactions and the formation of silicides. The likely reason for this is the generation of defects during the magnetron sputtering of indium.