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The activation method is proposed for collection of the sufficient statistics during the investigation of the nuclear astrophysical reactions at low energies with the short-living residual nuclei formation. The main feature is a multiple cyclical irradiation of a target by an ion beam and measurement of the radioactivity decay curve. The method was tested by the yield measurement of the 12 C( p ,γ) 13 N reaction with detecting the annihilation γγ- coincidences from 13 N(β + ν) 13 C decay at the two-arm scintillation spectrometer.

The results obtained by reconstructing of the experimental angular dependences of polarization tensors, the tensors of orientation of multipole moments, and the dynamical deformation of 24Mg nuclei produced in the 2+ state at 1.369 MeV in inelastic deuteron scattering on 24Mg nuclei at E d = 15.3 MeV for deuteron scattering angles between 25° and 165° in the laboratory frame are presented. The experimental results are compared with the results of calculations based on various versions of the coupled-channel method. The role of spin-orbit and tensor d 24Mg interactions is discussed along with the influence of the reorientation effect. The correlation features of the 2+ state of the 24Mg nucleus at 1.369 MeV that were determined in inelastic deuteron and alpha-particle scattering on 24Mg are compared.

Angular distributions of differential cross sections have been measured for elastic, inelastic scattering and the ( He 3 , d ) reaction on 6Li nuclei at the E lab ( He 3 ) = 34 MeV energy. The new and early obtained elastic scattering data at 34, 50, 60 and 72 MeV have been analyzed with Coupled Reaction Channels Method (CRC) taking into account triton transfer mechanism. The spectroscopic factors for t + He 3 configuration of 6Li were extracted. Parameters for real part of potential have been also calculated microscopically with double folding model. The differential cross sections for proton stripping to the 7Be ground and first excited states have been analyzed by modified DWBA and CRC methods at 34 MeV. The effect of triton and α exchange on proton transfer reaction Li 6 ( He 3 , d ) Be 7 for both ground and excited state is discussed. Spectroscopic factors and asymptotical normalization coefficients for p + Li 6 configuration of 7Be have been obtained from the experimental data.

Existing experimental data on elastic and inelastic deuteron scattering on 6Li nuclei in the energy range from 8 to 50 MeV were analyzed within the approach of coupled reaction channels. The coupling of elastic scattering and inelastic scattering accompanied by the transition to the 3+ state at E x = 2.186 MeV and the mechanism involving the exchange of an alpha-particle cluster were taken into account in respective calculations. The phenomenological potentials obtained from the present analysis describe well experimental angular distributions at all energies and in full angular ranges. The depths of the real and imaginary parts of the potentials in question depend smoothly on energy at fixed values of the remaining parameters. The energy dependence of relevant volume integrals agrees well with similar data for the p + 6Li, α + 6Li, and 12C + 12C systems and with the predictions of a microscopic theory.

The astrophysical S factors for the radiative-capture reaction 14N(p, γ)15O in the region of ultralow energies were calculated on the basis of the R-matrix approach. The values of the radiative and protonic widths were fitted to new experimental data. The contribution of direct radiative capture to bound states of the 15O nucleus was determined with the aid of asymptotic normalization coefficients, whose values were refined in the present study on the basis of the results obtained from an analysis of the reaction 14N(3He, d)15O at three different energies of incident helium ions. A value of S(0) = 1.79 ± 0.31 keV b was obtained for the total astrophysical S factor, and the reaction rate was determined for the process 14N(p, γ)15O.

The contribution of the direct radiative capture of protons by 10 B and 24 Mg nuclei at low energies to the astrophysical S -factors in the reactions 10 B (p,γ)11 C and 24 Mg (p,γ)25 Al have been calculated within the R-matrix formalism by using empirical proton asymptotical normalization coefficients (ANC). The ANCs for bound proton configurations {10 B +p} and {24 Mg +p} were obtained from the analysis of the reactions (3 He , d). The ANCs were also estimated from the values of the neutron ANCs in the mirror nucleus 25 Mg following the suggestion that the neutron and the proton in the mirror states have equivalent nuclear potentials. It has been found that the S -factor for the reaction 10 B (p,γ)11 C extrapolated to zero energy contributes ~100 keV b to the radiative capture to the ground state of 11 C . For the reaction 24 Mg (p,γ)25 Al the value S(0) gives 58 keV b with a direct capture contribution of 41 keV b .

At an energy of 25 MeV and in the angular range 7°−175° in the laboratory frame, angular distributions were measured for elastic deuteron scattering on 6Li nuclei and for the respective inelastic-scattering processes accompanied by the transitions to the ground state (1+) of the 6Li nucleus and to its excited state at E x = 2.186 MeV (J π = 3+). The resulting data were analyzed on the basis of the optical model of the nucleus and the coupled-reaction-channel method with allowance for the mechanism of alpha-particle-cluster exchange. It is shown that only upon including, in the analysis, channel coupling and the exchange mechanism can the experimental cross sections for elastic and inelastic scattering be reproduced over the entire range of angles.

A unified description of existing experimental data on alpha-particle scattering by 6Li over the broad energy range from 18 to 166 MeV was obtained with allowance for channel-coupling effects and mechanisms involving the exchange of a deuteron cluster. Angular distributions were analyzed on the basis of the optical model and the coupled reaction channels method. It was shown that the inclusion of channel coupling and the contributions from one- and two-step exchangemechanismsmakes it possible to describe special features of the behavior of differential cross sections for both elastic and inelastic scattering in a full energy range. Optimum values found for the parameters of optical potentials agree with the parameters of the global potential proposed previously for nuclei in the mass region A > 12.

Empirical values of the asymptotic normalization coefficient for proton bound states in the 14N nucleus for the first five levels were obtained from an analysis of the experimental differential cross sections known from our measurements and from the literature for the reaction 13C(3He, d)14N in the projectile-energy range between about 15 and 40 MeV. The values obtained in this way were used to calculate the astrophysical S factors for the reaction 13C(p, γ)14N in the case of the population of the first five levels of the 14N nucleus. The calculations were based on the R-matrix approach. The calculated values are in good agreement with the experimental astrophysical S factor at energies below 1 MeV.

The differential cross sections for the (3He, d) reactions on 16O nuclei at $$E_{3_{He} } = 42$$ MeV and on 19F and 26Mg nuclei at $$E_{3_{He} } = 22.3$$ MeV are measured for angles from the forward hemisphere. These data and those from the literature are analyzed by using a procedure that combines the method of distorted waves and the elements of the dispersion approach. It is established that the reactions in question are peripheral. Phenomenological values of nuclear vertex constants for proton separation are obtained both for the ground state and for low-lying excited states of the final nucleus, and the corresponding spectroscopic factors are evaluated. It is indicated that these data can be used for nuclear astrophysics.