Brief annotation and scientific rationale:

Information about neutron-nuclear interactions is extremely important for both fundamental and applied physics. The fact that the neutron has no electric charge makes it a unique probe for studying nuclear forces. Due to electrical neutrality, the high penetrating power of neutron radiation makes it promising for studying the structure of matter at both the nuclear and molecular levels. Neutrons are also widely used for applied purposes: in inspection systems, non-destructive elemental analysis facilities, in instruments for studying the immediate environment of boreholes (logging), as well as in the creation of neutron and gamma radiation detectors used on board orbital and descent spacecraft for analysis of soil and atmosphere of celestial bodies. Information about neutron-nuclear reactions is also necessary for the design of promising nuclear power facilities, as well as for modeling various devices and objects that interact with neutron radiation in one way or another. An indicator of the relevance of studying the characteristics of neutron-nuclear interactions can be the fact that the list of the most requested nuclear data for the most part consists of queries directly related to neutron-nuclear reactions.

The TANGRA (TAgged Neutrons and Gamma Rays) project is aimed at studying neutron-nuclear reactions using the tagged neutron method, finding new ways to use neutron methods in fundamental and applied research, improving existing and creating new approaches to processing the results of nuclear physics experiments. One of the tasks to be solved within the framework of the project is the interpretation of existing experimental data on the reactions of interaction of fast neutrons with atomic nuclei, their systematization and validation. The priority area of work is the acquisition of nuclear data.

Expected results upon completion of the project:

Expected results of the project in the current year:

1. Measurements of total and differential cross sections of characteristic gamma lines for various elements using high-resolution detectors of g-rays.

2. Development of an experimental setup for studying (n’γ) correlations and performing test measurements.

3. Implementation of a part of the experimental program for the development and verification of a methodology for measuring carbon concentrations in soil.

4. Simulation of a facility for measuring carbon concentration in soil to develop a method for deep profiling of macroelement concentrations.

Brief annotation and scientific rationale:

The project is aimed at modernizing the main systems of the electrostatic charged particle accelerator EG-5, developing ion-beam and complementary methods for studying the elemental composition and physical properties of near-surface layers of solids.

Goals of the project: to provide technical feasibility for the implementation of the scientific program of the JINR Topical Plan in studying reactions with fast quasi-monoenergetic neutrons; development of nuclear physics methods for studying the elemental composition; solution of problems of neutron-radiation materials science; implementation of practical applications of neutron physics; ensuring technical feasibility for the implementation of the unique options of the microbeam spectrometer.

Objectives of the project. The main technical task of the project is to restore the energy range of accelerated particles of 900 keV - 4.1 MeV and increase the ion beam current to 100-250 μA while maintaining the energy stability of the ion beam at a level no worse than 15 eV, ensuring the spatial stability of the ion beam, sufficient to implement the option of the microbeam spectrometer / nuclear microprobe.

The main organizational task is the formation and development of human resources potential to ensure the full implementation of the project for at least 3 seven-year periods.

The objectives of the project also include the upgrade of the experimental infrastructure of the accelerator complex, in particular, the development of new methods for studying the physical properties of the surface of materials that can complement and improve the quality of the obtained scientific results, the intensification of international scientific and technical cooperation, the organization of user policy, the formation of an interlaboratory accelerator center on the basis of FLNP JINR to solve a wide range of unique scientific and technological problems.

The main criteria for the successful implementation of the project are providing a neutron flux sufficient to conduct nuclear physics experiments with fast neutrons, and an energy stability of the ion beam sufficient to create a microbeam spectrometer/nuclear microprobe.

Expected results upon completion of the project:

As a result of the implementation of the project, the technical parameters of the accelerator will be restored (energy of accelerated particles of 4.1 MeV at a maximum current of at least 100 μA), which will make it possible to conduct studies of reactions with fast neutrons at JINR, as well as provide technical conditions for the installation of a microbeam spectrometer. A neutron generator based on a solid-state lithium target with a moderator will be added to the existing neutron generator with a gas target, and the chamber for irradiating samples with ion beams will be modified.

A new specialized laboratory will be created for the preparation of objects of study, which will be equipped with complementary methods for studying the optical and electronic properties of the surface, such as ellipsometry, optical and electron microscopy, methods for studying electrical properties at direct and alternating current (voltammetry, impedancemetry).

In addition to modernization and expansion of the instrumental base of the accelerator complex, the formation of personnel potential for the next 20-30 years will be carried out. The available methods of elemental analysis will be supplemented by methods of analysis based on prompt gamma rays from inelastic neutron scattering and neutron activation analysis.

Modernization of EG-5 at JINR, where there are highly qualified specialists, good detecting equipment and valuable developments in the field of neutron investigations of atomic nuclei, will make it possible in the short term to conduct a number of new, unique experiments on obtaining the energy spectra and angular distributions of charged particles from (n, α) and (n, p) / (α, n) and (p, n) reactions and integral and differential cross sections of the latter in the neutron energy range up to ~6 MeV, on processes of fission of atomic nuclei by fast neutrons, activation analysis, experiments in the field of neutron materials science and etc.

Expected results of the project in the current year:

- certification and commissioning of the EG-5 accelerator and its experimental halls in test mode;

- replacement of the worn high-voltage accelerating tube and ion source that has lost its performance characteristics.

- reaching an ion beam current of over 100mkA;

- improvement and adjustment of the parameters of the ion optics of the EG-5 accelerator (reconfiguration from the focussator mode to the condenser);

- modernization and automation of the gas cylinder economy, adaptation of the technological scheme;

- modernization of the vacuum system;

- automation of all accelerator service systems;

- launch of a laboratory for engineering and sample research using complementary ion-beam methods;

- formation of the personnel potential of the group;

- implementation of technical projects, in particular, a project with JSC "Micron" "Carrying out preparatory work, including the manufacture of an ion beam scanning system in a raster, as well as test electron beam processing and testing using impedance spectroscopy of semiconductor wafers with a diameter of 150 mm in an amount of up to 20 pcs.", a technical project with the State Corporation "ROSATOM" "Investigation of the dependence of the sensitivity of the UDKN-04R device on neutron energy", projects with Angstrom JSC, etc.

Brief annotation and scientific rationale:

Nuclear processes and structural changes in materials induced by slow, resonance and fast neutrons and accelerated charged particles are traditionally in the focus of research attention at FLNP JINR. The interaction of neutrons with atomic nuclei is of interest for both fundamental and applied research.

The integrated use of the FLNP basic facilities (IREN pulsed source of resonance neutrons, IBR-2 pulsed reactor, EG-5 electrostatic generator) makes it possible to conduct nuclear physics research in a wide range of neutron energies from cold neutrons to ~20 MeV, and the use of external neutron sources, such as the n_TOF neutron time-of-flight facility at CERN, allows expanding the energy range to several hundreds of MeV. Fundamental research carried out at the FLNP Department of Nuclear Physics includes studies on the violation of space and time symmetry, the mechanism of nuclear reactions, the structure of atomic nuclei, fission processes induced by neutrons, neutron-induced reactions with the emission of light particles, the properties of the neutron as an elementary particle, the properties of ultracold and very cold neutrons, quantum mechanical effects involving neutrons.

Also, in FLNP, a variety of research programs has been developed for applied investigations, such as obtaining nuclear data and information on the radiation resistance of materials for nuclear technologies, power engineering and transmutation, radiation mutagenesis on fast neutrons, neutron activation analysis using thermal and epithermal neutrons, neutron activation analysis using prompt gamma-rays, elemental analysis using neutron resonances, elemental analysis using fast neutrons, analysis of the elemental composition of thin films, investigation of the radiation resistance of materials to the effects of accelerated charged particles on electrostatic accelerator beams, development of radiation-resistant nanostructured materials using accelerated ion beams.