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Abstract  

Using extracted electron beam from the 30 MeV microtron of IPP a thermal neutron source was built for activation analysis. Combined (Ta–Pb)-target is used as a gamma-neutron converter, and high-pressure polyethylene is used as a moderator. For the purpose of activation analysis special channels of different sizes were made in the moderator, with, in particular, a large pocket of about 103 cm3 in volume for irradiation of extended objects. Detailed spatial neutron flux distribution was measured, and the neutron flux density is of the order ofn·109 n·cm–2·s–1. The set up was used for detemination of Sb, As, V, Cr, Mn, Ni, Ga, Br, Re, Cd, REE content in oil, fuel oil, petrol, gaseous condensate under normal conditions. The sensitivity of noble elements determination in non-destructed loaded boards approaches 1 mg of total mass in the assembly, and equals 0.05 ppm for Au detemination in rocks and minerals.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
V. Samosyuk
,
V. Firsov
,
B. Chapyzhnikov
,
T. Kiseleva
,
V. Rodionov
, and
M. Shtchulepnikov

Abstract  

Oxygen and carbon concentrations up to 0.06 ppm and 0.03 ppm respectively were determined in high purity metals such as Fe, Cu, Nb, Mo, In and some others. Analytical procedures and results of the determination of alloying additives in a number of rare metal alloys are given. The relative standard deviation constitutes 0.02 to 0.04. Accuracy of the procedures used is confirmed by a comparison of experimental results with those of the other analytical methods. Experimental data on the sensitivity of determining 35 elements are reported on irradiating them with thermal neutrons and a bremsstahlung emitted by the microtron. For most elements (for radioactive isotopes having a half-life of above 2 min.) sensitivity of the analysis is 10−6 to 10−8, g, at the microtron current of 30 μA and irradiation time of less than 10 min.

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Abstract  

The biokinetics of radioactive substances can be studied using stable tracers. For the highly radiotoxic actinides, for which no stable isotopes are available as tracers, the use of stable isotopes of lanthanides as chemically related surrogates has been suggested. In this work, the possibility of using activation analysis with protons, photons, or thermal neutrons for the determination of single stable isotopes of gadolinium in biological samples has been tested. All the techniques show very good linearity response, and may be considered as complementary. Whereas activation analysis with protons is recommendable for the simultaneous determination of two different isotopes, neutron and photon (gamma) activation analysis should be chosen whenever a better sensitivity or simplicity of the analysis is required.

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Abstract  

Information on the biokinetics of cerium can be obtained directly from humans by using stable isotopes as tracers. Neutron, photon and proton activation analysis have all been tested as analytical techniques able to quantify different isotopes of the same element in biological fluids. The experimental conditions were optimized for Ce analysis in blood plasma samples. The performances of the different techniques have been explored. The simultaneous determination of two Ce isotopes with the required sensitivity in the order of few ppb is difficult to obtain using a single technique, and, therefore, a combination of techniques can be envisaged.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
T. Mamedov
,
I. Chaplygin
,
V. Roganov
,
V. Firsov
,
O. Ilyukhina
,
V. Kudinov
,
E. Minaychev
,
Yu. Obukhov
,
G. Savelev
,
V. Evseev
,
V. Gordeev
,
R. Konopleva
,
L. Gordienko
, and
V. Khadji

Abstract  

SR-method has been used for studying reactions of muonium as an analogue of a light hydrogen isotope with impurity atoms and point-like defects. The relaxation rate of muonium polarization Mu was measured for 11 samples with different concentrations of impurity atoms and defects. The rate constants of reactions of muonium with Fe, Al, Li, Ba, Cu, Mn, Ti and Pb atoms in quartz were defined.

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