The paper presents the results of experiments on measuring the cross sections for elastic scattering and nucleon transfer channels in the 6Li+9Be reaction at an incident energy of 68 MeV: 9Be(6Li,6Li)9Be, 9Be(6Li,7Li)8Be, 9Be(6Li,7Li)8Be2+, 9Be(6Li,8Li)7Be, 9Be(6Li,7Be)8Li. The aim is to reveal the manifestation of the cluster structure of 9Be. Theoretical analysis of the contributions of one-step and two-step neutron transfer mechanisms is performed using the distorted wave Born approximation method with the Fresco code. Good agreement between the calculations and the experimental data was obtained for the channels of elastic scattering 9Be(6Li,6Li)9Be, neutron 9Be(6Li,7Li)8Be and proton transfer 9Be(6Li,7Be)8Li, as well as the transfer of two neutrons 9Be(6Li,8Li)7Be. It is shown that the dineutron cluster transfer mechanism makes a dominant contribution to the 9Be(6Li,8Li)7Be reaction channel at forward angles.

An Erratum to this paper has been published: https://doi.org/10.1134/S0020441224050014

The energy spectra of alpha particles emitted at an angle of 0 $${}^{\circ}$$ in the interaction of 400-MeV $${}^{56}$$ Fe ions with $${}^{238}$$ U, $${}^{181}$$ Ta, and $${}^{9}$$ Be targets were measured by means of a high-resolution magnetic analyzer (MAVR, which is the acronym of the Russian name of this setup). The energy spectra of charged particles ranging from Li to Ne were also measured. The experimental data obtained in this way indicate that the emission of alpha particles is a dominant process in the above reactions. Particles of high energy, up to those in the vicinity of the so-called kinematical limit for two-body reactions, were observed with a rather high yield. The sensitivity of the experimental procedure that employed the aforementioned magnetic analyzer made it possible to observe events characterized by cross-section values smaller by six to eight orders of magnitude than that at the maximum of the spectrum. The cross section for the production of light particles is shown to be dependent on their binding energy in the target. The experimental data obtained in this study were analyzed with aid of the moving-source model.

The energy spectra of alpha particles from reactions induced by 280-MeV $${}^{48}$$ Ca beams incident to $${}^{181}$$ Ta, $${}^{197}$$ Au, and $${}^{238}$$ U targets were measured at an angle of 0 $${}^{\circ}$$ by means of a high-resolution magnetic analyzer (MAVR setup). The sensitivity of the procedure used made it possible to measure alpha-particle yields that are five to six orders of magnitude less than the maximum yield. The cross section for the formation of alpha particles is shown to be dependent on their binding energy in the target nucleus. The experimental data obtained from these measurements were analyzed on the basis of the model of two- and three-body reaction channels and the model of moving sources.

Inclusive energy spectra have been measured for light charged particles emitted in the bombardment of Ta target by48Ca ions at 261 MeV and 471 MeV. The reaction products were analyzed and detected by means of a (∆E-E) telescope placed in the focal plane of a magnetic spectrometer located at forward angles with respect to the beam direction. In all the reactions studied light charged particles with an energy close to the respective calculated kinematic limit for a two-body exit channel are produced with relatively great probability. The results obtained make it possible to draw some conclusions about the reaction mechanism involving the emission of light charged particles.

Neutron-removal cross-section ( σ-xn ) measurements of neutron-rich light nuclei were performed on the COMBAS fragment-separator with a multi-detector Si telescope at intermediate energies (22-34) MeV/nucleon. The removals of one neutron from8Li and9Be, two neutrons from6 He and10 Be and four neutrons from 8 He were observed from the reactions on a Si-CsI(Tl) telescope. Results of σ-xn for6 He,8 He,8 Li,9 Be and10 Be nuclei were obtained and compared with those of previously measured data. The data indicate that4 He is a good core within6 He and8 He. Furthermore, we found that9,10 Be nuclei disintegrated by one- and two- neutron removal reaction, respectively.

The heavy-ion reactions are characterized by a large number of channels, differing in various characteristics (angular distributions, mass distributions, kinetic energy, reaction cross sections, etc.). The major characteristics of two complex nuclei interaction processes is the mass distribution of reaction products. Therefore, one of the main features of the experiment is a direct measuring of the reaction products masses. This is directly achieved by measuring the masses of the forming nuclei. This paper describes the results of direct measuring of the reaction products masses using a precision time-of-flight technique. Tn this technique, microchannel plates (MCP) are used as the start and stop detectors. Using the 25 cm path length, time resolution of 240 ps was obtained, which made it possible to determine the nuclei masses with an accuracy of +/- 5 amu. The technique is applied in experiments to measure the heavy nuclei fission fragments characteristics (mass distribution and total kinetic energy), in reactions of complete and incomplete heavy ions fusion with nuclear targets.

A time-of-flight system was created to register the reaction products and perform correlation measurements on a high-resolution magnetic analyzer (MAVR). The facility is located on the channel of the extracted beam of the U-400 cyclotron at the Laboratory of Nuclear Reactions JINR. The results of measuring the parameters of the time-of-flight spectrometer obtained on the basis of measuring the spontaneous fission fragments velocities of 252Cf are described. In addition, the results of the measurement of fission fragments in the 48Ca+238U reaction are presented. In this case, two time-of-flight arms were used, with the help of it is planned to carry out correlation measurements of induced fission fragments of a complex system. The created system also makes it possible to carry out correlation (three particles) measurements of fission fragments with particles registered in the focal plane of the MAVR magnetic spectrometer. Another purpose of the described system is to register elastically scattered ions, which is used as a monitoring system for the quality and composition of the beam hitting on the target of the MAVR facility.

Secondary beams (6Li,7Be,8B) were obtained by the separation of fragmentation products of a15N ion beam (50 MeV/A) impinging on a Be target using the COMBAS spectrometer. The secondary products were detected by a telescope consisting of five Si-detectors (dE) and a stop CsI(Tl) detector. The telescope allowed us to achieve unambiguous particle identification of fragments originating from incident secondary beams as well as their reaction products resulting from interaction with the Sidetectors, chosen as a secondary target. This way, break-up reactions of6Li,7Be and8B have been studied in this experiment, in particular the longitudinal momentum distributions of7Be fragments in the break-up of8B on a Si have been measured at 30 MeV/A.

The availability of new radioactive ion beams has broadened the study of nuclear reactions and nuclear structure. The main mechanism to produce the secondary beams is the fragmentation of the projectile. An alternative method for the production of the exotic nuclei is the multinucleon transfer. We measured production cross section for the B, C, N and O isotopes in the reaction 18O + Ta and the beam energy at 10 MeV/nucleon. The cross-sections were obtained by integrating the momentum distributions of the isotopes. It was shown that in deep inelastic processes the production yields of different isotopes could be well described using statistical models and could also be explained by the Qgg-systematic.

Within the study of the time-of-flight method, an appropriate system has been created and the first test data have been obtained that fully demonstrate the efficient operation of the equipment. An MCP detector is used as the start detector. During the experiment at this facility, the time resolution, depending on parameters of the reaction products (mass, charge, and energy), has been measured. The characteristics of the detector operating at the IC-100 accelerator (FLNR, JINR) have been measured. The results demonstrate a high time resolution for charged particles in a wide mass range.

Secondary beams (6Li,7Be,8B) obtained by separation of fragmentation products of 15N beam (50 A MeV) impinging on a Be target using COMBAS spectrometer. The secondary products will be detected by a telescope consisting of five Si-detectors (dE) and CsI(Tl) detector (Er). By the dE-E method, the telescope allowed us to achieve unambiguous particle identification originating from incident secondary beams as well as theirs reaction products resulting from reactions with one of Si detectors chosen as the target. Accordingly, break-up reactions of 6Li, 7Be and 8B were studied in this experiment.

Neutron-removal cross-section ( σ -xn ) measurements of neutron-rich light nuclei were performed on the COMBAS fragment-separator with a multi-detector Si telescope at intermediate energies (22-34) MeV/nucleon. The removals of one neutron from 8 Li and 9 Be, two neutrons from 6 He and 10 Be and four neutrons from 8 He were observed from the reactions on a Si-CsI(Tl) telescope. Results of σ -xn for 6 He, 8 He, 8 Li, 9 Be and 10 Be nuclei were obtained and compared with those of previously measured data. The data indicate that 4 He is a good core within 6 He and 8 He. Furthermore, we found that 9,10 Be nuclei disintegrated by one- and two- neutron removal reaction, respectively.

Using high-resolution neutron diffraction, microstrain was investigated in three series of samples of stainless austenitic dispersion-hardened steels, which are used as various structural reactor components. The effect of temperature and duration of heat treatment on the precipitation of dispersion-hardened phase particles, as well as on lattice parameter changes and microstrain, was studied. An increase in microstrain upon coherence failure was observed in all the steels.