(Head – Professor, Academician of National Academy of Sciences of Ukraine I. M. Vyshnevskyi)
Laboratory for theory of nuclear interactions and processes
Main directions of scientific activity:
· Experimental studies of structure and properties of atomic nuclei exited states that are filled as in radioactive decay, as in charged particle beams.
· Study of nuclear reaction mechanism by isomer relation method and on charged particle beams.
· Study of atom-nucleus processes that take place with participation of coupled atomic electrons.
· Study of higher order effects in the radioactive decay processes and in gamma-rays internal conversion.
· Studies of the consequences of Chornobyl accident influence on the environment and on human being.
· Development and creation of modern semiconductor spectrometers with spectrum processing programs.
The most important scientific results:
· For the first time a new phenomenon – nuclear excitation of non-photon positron annihilation coupled electrons of atom was uniquely established.
· Structure and properties of atomic nuclei in the range 90≤A≤120 was studied. More than 300 new nuclear states were found. For the first time more than 1000 gamma-transitions were observed. Multipole composition of more than 200 gamma-transitions was found in correlation measurements. States which belong to three- and four-phonon multipletes were established unambiguously. Systematic presence of magnetic multipolity in phonon transitions was observed. Boson theory for nuclei at A≈100 region was developed.
· For the first time satellite gamma-transitions that accompany the process of internal conversion at 93Nb, 121Sn, 193Ir nuclei were observed. Theory of this process was created which could be described by Feinmann diagrams of fifth order.
· For the first time excitation of atom at β־-decay, e-capture, as well as in internal process of conversion at ultra-low transition energy was studied. Dominant role of direct processes was shown.
· For the first time decay of nuclear state trough the virtual states with simultaneous irradiation of gamma-quantum and electron of conversion was studied.
· Isomer relations in reactions with light charged particles in 0 - 100MeV energy range were measured. For the first time a significant contribution of pre-equilibrium and internal-nuclear cascades of 50 - 100 energy range in (p,n) and (α,n) reactions was observed. New data about isomer relations in neutron and gamma-quanta fission products were obtained. Fission theory which describes average angle moments measured by isomer relation method was elaborated.
· Numerous studies of Chornobyl accident consequences were undertaken. More than 20000 probes were tested on 137Cs content, above 3000 probes on 90Sr content and more than 500 probes on alpha-nuclide content. Special programs for calculation of external doses and inhalation irradiation were created. Works on retrospective restoration of radiation situation within 30-km zone during the first days of accident was accomplished.