Interaction of electrons and photons of intermediate energies (up to 2 GeV) with nuclei.
Quantum electrodynamic processes in substance, including crystals.
Mechanisms of nuclear reactions and structure of nuclei investigated with heavy nuclei and low-energy multicharged ions.
Nuclear methods of investigating the structure and properties of substance. Radiation technologies.
Basic results of recent years
INTERMEDIATE-ENERGY PHYSICS (up to 2 GeV)
Comprehensive studies are made of polarization parameters in reactions of meson photoproduction on protons and neutrons, amplitudes of these processes are unambiguously determined. The probability of quadrupole delta-resonance decay is obtained to confirm the idea about the tensor nature of quark interaction in the nucleon. The experiments have confirmed the hypothesis about a partial conservation of the axial vector current; the contribution of the isotensor component to the electromagnetic hadron current is calculated.
Studies of photo- and electrodisintegration of the deuteron and of He3 and He4 nuclei are carried out, showing evidence for dibaryon resonances in these processes.
The hexadecapole resonance of electron-excited nuclei and the supergiant resonance in nuclear photofission are discovered.
A new phenomenon is disclosed, namely, a delayed fission of subactinide nuclei (bismuth 209) with a lifetime of 0.3 ns at irradiation with electrons. The mechanism of this phenomenon, i.e., production and disintegration of the hypernucleus, is proposed.
Theoretical and experimental research is made into the interaction of high-energy charged particles with substance and intense external fields. Different mechanisms of radiation caused by energetic electrons and positrons in crystals, are identified and investigated. New methods are offered to produce beams of intense, directed, monochromatic and polarized photons in x-ray and gamma-ranges for research use in the fields of nuclear physics, solid-state physics and radiation physics.
LOW-ENERGY PHYSICS
New fundamental data on nuclear states and nuclear reaction mechanisms are obtained, including data on highly excited nuclear states (high-spin isomers; nuclei far from the stability region). Systematic studies of M1-resonance in sd-shell nuclei are performed. The role of neutron-proton pairing in these nuclei is elucidated.
Analog and antianalog states in medium nuclei are investigated; the behavior of radiation power functions, partial and total cross-sections, and also the applicability of the statistical theory for their description are studied. The method of heavy particle channeling is used to study at an atomic level the structure of crystal defects in semiconductors, metals, magnetic materials and high-temperature superconductors. Localization of light elements, implanted or dissolved in the crystal lattice, is defined.
Procedures and equipment are devised for the analysis of structure and composition of substances with nuclear methods using heavy particle accelerators and also instant nuclear reactions, backscattering and characteristic x-ray radiation.
ACCELERATOR FACILITIES
The large electron linear accelerator (LUE-2000) has been upgraded. This has led to an increase in electron energy from 1.6 GeV to 2.0 GeV, a 20-fold increase in the accelerated current (up to 100 mA in a pulse), and to the improvement of beam monochromaticity by order of magnitude.
Devised are:
a new accelerating structure with an accelerating gradient of 25 MeV/m;
a new RF power source, namely, a 40 MW klystron with 50% efficiency;
two prototypes of new-class 60 MeV electron accelerators with the use of new constant-gradient accelerating structure (structure length being 3 m).
The theory of beam instability suppression in linear accelerators is developed.
A pilot batch of accelerating installations "Sokol" designed for nuclear microanalysis is introduced into industry.
A high-current electron accelerator (energy - 10 MeV, current - 1 mA, radiation power - 10 mrad/s) is created for applied purposes.
Methods of updating and improving the quality of electrotechnical characteristics of the industrial equipment are developed.
THE ELECTRON LINEAR ACCELERATOR LUE-2000
Process of in-bulk photonuclear doping of silicon by the use of the linear accelerator is developed.
High-duty cryogenic vacuum pumps based on the use of liquid neon are devised.
