[en] The problems of experiment planning in the neutron activation analysis of soils and plants to improve the accuracy of the determination of an element composition by choosing optimal parameters of analysis regime have been considered. Three types of tasks are possible for the mass analysis of soils and plants at the given productivity: a quantitative analysis for determining one component with maximum accuracy; a quantitative analysis for determining separate components with the given accuracy; a quantitative analysis for determining components with a certain confidence. Various criteria permitting to solve the above problems are suggested

[en] Neutron activation analysis is a method for quantitative determination of trace amounts of selected elements regardless of their physical and chemical states in any material. The principles of the method are explained and the method is described. (K.M.)

[en] The instrumental neutron activation analysis (INAA) is briefly described and its use is discussed in geology and in mineral raw material prospecting. A nuclear reactor or a neutron generator is used as a neutron source. A multichannel gamma spectrometer and computer technology are used for the evaluation of results. Activation in a nuclear reactor using a high thermal neutron flux is suitable for simultaneous determination of a wide range of medium a heavy elements in low and trace concentrations, mainly elements from the rare earth group and Hf, Ta, Sc, Sb, Th, U, this especially when only a small amount of the specimen is available. It is not suitable for determining macroconcentrations of elements easily determinable by other methods. Fast neutron activation using a neutron generator is mainly suitable for the determination of some light elements forming the geological sample matrix. INAA is advantageous for ease of automation which allows analysing several hundred samples in a working shift with the minimal demands on the number of personnel. (Ha)

[en] The principles of neutron activation analysis (NAA) are explained. Applications in the fields of science, industry, history, art and law are described. The use of the Slowpoke-2 reactor at Dalhousie University (Canada) for NAA is described. A Table is given of sensitivities for analysis of elements by NAA. Standard reference materials are listed under various headings (geochemical, biochemical, environmental) and the names and addresses of international centres for NAA, in 28 countries, are given. (U.K.)

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[en] The possibilities offered by non-destructive neutron activation analysis (NAA) for simultaneously determining a large number of micro- and macro-components in plant samples of Bulgarian origin have been studied. Three groups of elements are determined: short half-life isotopes: Al, Mg, Ca, Na, Mn, Cl, Cu; medium half-life isotopes: Br, Na, K; and long half-life isotopes: Fe, Cr, Co, Sc, Pb, Zn. The samples are kept for 1 minute in a fluxes of 6x10¹² n.cm².sec^-1 (first group), and of 3x10¹¹ n.cm².sec^-1 for 18 hours (second and third groups). Use is made of a Ge/Li detector and 4000-channel analyser. To test the accuracy of the method, the results of NAA for some standard specimens have been compared with the indicators of other conventional methods tested in 18 laboratories in various countries. The data from NAA for the content of K, Mo, Ca, Mn, Fe, Zn and Cu demonstrate a high degree of coincidence with those from the other methods. Chemical composition of 23 samples of experimental and field crops is determined

[en] The invention concerns a radioisotopic composition analysis process of a sample of material, and the device for putting it into operation. The device and the process allow to take into account the influence of background due to induced radioactivity of isotopes, which do not make the object of the analysis. The sample is firstly rotated and irradiated at a speed corresponding to the presence of the activated isotope in the material, and afterwards, at a speed to which the activation of the same isotope is practically absent. The number of speeds selected for operating the irradiation is equal or greater than the number of radioinduced isotopes to be measured. This procedure allow to stablish an adequat number of speeds in case of analysis of several materials joining isotopes having different half lives

No abstract available

[en] The trace element content of DGG standard glass I was determined with a view to comparisons with antique glasses. Furthermore, this glass will be used in further investigation as a standard for trace element analysis of soda-lime glasses. (orig.)