[en] The delayed-neutron spectra of four groups for U-235 thermal neutron fission were reconstructed from experimental information obtained by two-dimensional method. The average energies of spectra and relative yields were calculated. Some possibilities of the two-dimensional method were pointed to control the obtained results, which were compared with data of other authors. 5 refs.; 6 figs.; 1 tab

[en] Coupled channel method was used for analysis of the low-energy neutron strength functions and cross sections for ^116,118,120Sn isotopes. The account of neutron inelastic scattering channels with excitation of low-lying collective states into the coupled channel method gives the possibility of description of the experimental data without introducing of the strong energy dependence of the parameters. 14 refs.; 3 figs.; 1 tab

[en] Revision of ⁹³Nb evaluated neutron cross section file for the BROND library is performed. The new file option comprises revised functions of inelastic scattering excitation levels, energy-angular distributions of secondary neutrons, γ-quantum spectra and production cross sections. The evaluation is performed within the framework of optico-statistic approach (functions of level excitation under inelastic scattering, secondary neutron energy-angular distributions) or analysis of experimental data (γ-ray yield cross sections and γ-quantum spectra).The analysis results are used when forming a new option of ⁹³Nb file for the BROND evaluated neutron cross section library. 42 refs.; 6 figs.; 1 tab

[en] Cross section of ²⁷Al(n,α)²⁴Na reaction was measured by activation method at neutron energy of 14.8 MeV. Its value was obtained being equal to (110±2) mb. Neutron fluence rate was measured with an uncertainty of less than 1%. Measurement of induced activity was carried out by beta-gamma-coincidence method and by scintillation gamma-spectrometer. 8 refs.; 1 tab

[en] Dependence of neutron radiation capture cross sections on the parameter of neutron excess of mean and heavy mass nuclei at 0.5-2 MeV neutron energy is ascertained on the base of the cross section exponential dependence on the reaction energy. An adequate description of experimental data on the nucleus neutron radiation capture cross sections by an isotopic dependence allows one to evaluate cross sections of ^95,97Nb, ¹⁰⁵Rh, ¹⁰⁶Ru, ¹¹¹Ag, ^129,131I, ¹³²Te, ¹³⁵Cs and ¹⁴⁴Ce nuclei-fission products difficult to be measured. Comparison to the data available is made. 16 refs.; 4 figs.; 1 tab

[en] Consideration is given to the main representations of the current theoretical description of excited nuclei level density. An essential role of consistent consideration of shell and collective effect is demonstrated in the analysis and systematics of experimental data: neutron resonance density, evaporative spectrum of particles, energy dependence of nuclear fissilities by neutrons, light and heavy charged particles. 34 refs.; 7 figs.; 1 tab

[en] The quality of introducing heterogeneous and bilinear resonance corrections to calculations of central reactivity coefficients of standard materials possessing well-known cross sections is investigated using the critical assemblies -BN-600 type reactor models - with different degree of the fuel heterogeneity. For this purpose necessary measurements are performed. Heterogeneous and bilinear resonance corrections are obtained by two methods: on the base of integral-transport approximation and a more correct approximation, developed by Heinzelmann B., accounting in particular, the dependence of neutron flux and validity on the direction of their scattering. It is shown that the reactivity method is a reliable instrument of testing the accuracy of calculating the balance of fissions and captures in fissionable elements. 10 refs.; 1 fig.; 6 tabs

[en] Averaged cross sections for ⁶⁴Zn(n,p)⁶⁴Cu, ⁹⁰Zr(n,2n)⁸⁹Zr, ¹¹¹Cd(n,n')^111mCd were measured for ²³⁵U fission neutron spectrum. These results are 34.4±0.8 mb, 0.0945±0.045 mb, 198±4 mb respectively. The emission of the photons with 0.52 MeV for ⁶⁴Cu was used 0.343. Evaluated cross sections are 33.8±0.7 mb and 0.0966±0.0024 mb for Zn and Zr. There are not the publication for Cd therefore the evaluation was not made. 12 refs.; 6 tabs

[en] Effect of uncertainty of knowing the mean ²³⁸U resonance parameters on the calculation of the factor of self-shielding of a total cross section and the radiation capture cross section and the corresponding Doppler increments is investigated. It is shown that an uncertainty, present in the neutron strength function S_n⁰ ∼ (0.9-1.2)x10^-4 produces a weak effect on the radiation capture cross section self-shielding description. The effect of the total cross section self-shielding depends on S_n⁰ value, but the requirements to the accuracy of its description are met under the uncertainty present in the neutron strength function. 26 refs.; 5 figs.; 1 tab

[en] Questions related to application of the BRAND program complex, simulating the processes of neutron radiation transfer by Monte Carlo method for analysing the results of measuring the cross sections by activation method, are considered. Results of calculating the corrections to neutron scattering in the air, in the activated sample, which are compared to results by other authors, are presented. The problem of choosing sufficient statistical accuracy of calculation results obtained is considered, choice criterion is proposed and grounded on the base of analysing the calculation results obtained. Questions related to possibilities of applying the complex when planning the forthcoming experiments, analysing experimental results, are discussed and the desired directions in extending the BRAND program complex capabilities are indicated as well. 8 refs.; 4 figs.; 1 tab