[en] The optimal method of sample preparation for the X-ray spectrometric analysis of iron ores composition has been elaborated. Because of a large effect of mineralogical and other influences occuring during X-ray fluorescence analysis of iron ores the application of fusion technique is necessary. Three variants of sample preparation by this technique are discussed in the paper. In the first case sodium tetraborate was used as a fusing agent and the obtained melt was crushed and tablets were pressed. In the second variant lithium tetraborate was used as a fusing agent and the obtained melt was poured into special platinum form to obtain a borax bead ready for measurement. The third variant differed from the second by using the analytical line of the internal standard CoKssub(α) in iron determination in the ore samples. Evaluation of the obtained results has been carried out using Student's t-test. (author)

No abstract available

[en] The samples of natural ores and synthetic standards were prepared by melting with lithium tetraborate as a fusing agent and with lanthanum oxide as radiation attenuating agent. For preparation of beads containing samples of synthetic ores, 5% and 10% solid solutions of proper oxides in lithium tetraborate were used as substrates. On the basis of the obtained results the linear regression equations for Fe, SiO₂, Al₂O₃ and CaO have been evaluated. On the basis of these equations the usefulness of synthetic standards was estimated. For comparison of iron ores natural and synthetic standards Student test was applied. (author)

No abstract available

[en] Angular distributions of alpha particle emitted in the ⁹Be (n,α)⁶He reaction were measured at neutron energies equal to 12.2, 14.1 and 18.0 MeV. Neutrons were produced in the ³H(d,n)⁴He reaction. These distributions do not differ significantly, thus confirming an earlier suggestion that direct processes are mainly responsible for the reaction. An attempt was made to analyze the distibutions assuming two modes of the reaction. The first mode is a heavy particle stripping of ⁵He and implies a ⁴He + ⁵He structure for the ⁹Be nucleus. The second mode corresponds to a pick-up of ³He with the ⁹Be nucleus considered as ³He + ⁶He. The reasonable fit was obtained in the whole neutron energy range with a predominant heavy particle stripping contribution

No abstract available

No abstract available

[en] Angular distributions of α-particles emitted in the ⁹Be(n,α₀)⁶He and ⁹Be(n,α₁)⁶He reactions have been measured at neutron energies of 12.2, 14.1 and 18.0 MeV. Excitation functions for forward emission of the reaction products have been determined in the neutron energy range 12.2-18.0 MeV. The results indicate the dominance of heavy particle stripping in the mechanism of the ⁹Be(n,α₀)⁶He reaction in the investigated neutron energy range. (Auth.)