Division of nuclear reactions

Short name: DNR

Phone: +7 495 939 50 92


Division of Nuclear Reactions

Division of nuclear reactions (DNR) is leaded by Sc.D., Professor Oleg Yuminov.

The main directions of scientific activity of DNR include studies of nuclear reactions mechanisms, structure of atomic nuclei and lead time of fission for heavy nuclei.

The foundation for this research was laid in 1965 by the State Prize Laureate Professor A.F.Tulinov, who found out a new physical phenomenon - shadow effect, wich appears at the interaction of charged particles and monocrystals.

On this basis a new experimental methods of direct measurements of ultra-short lead time of nuclear reactions within the range of 10−14 — 10−19 seconds was developed. The scientists of the Division have predicted and experimentally found delay of heavy nuclei induced fission due to the lifetime of excited nuclear state in the second potential energy well. Studyies of this delay allowed to obtain unique information about the density of the levels, energy ependence of shell effects and about the type of symmetry of fissionable nuclei shape in the second potential energy well. A developed dynamic-statistic model for nucleus fission allows to describe a wide variety of the observed processes (angular anisotropy of the fission yield, fission probability, lifetimes, etc.) from one and the same point of view.

The influence of alfa-claster structure of the projectile nucleus on the secondary charged particles yield in the reactions 16O+65Cu->81Rb and 19F+62Ni->81Rb was theoretically evaluated. It was shown that experiemtnal measurement of secondary alfa-particles yield in these reactions can become a direct experimental proof of alfa-claster structure of oxygen nucleus.

A series of studies concerning development of dispersive optical model is conducted by the team of Professor Evgeny Romanovsky. Dispersive optical model allows to take into account effect of correlations between one-particle, collective and more complicated movements of nucleons in the nucleus by means of import dispersive component into potential describing of the nucleon scattering by the nucleus. These studies allowed to find out shell effects for a number of nuclei near the area of nucleon instability.

Research team leaded by Professors Anna Popova and Vyacheslav Komarov studied multiparticle quantum systems theoretically and experimentally in cooperation with an exerimental group of Marburg University (Germany). one of the studied directions concerned big organic molecules in a periodic electromagnetic fields of IR laser type.

It was found out that:
- substructures of hydrocarbon chain type in this molecules are a antennas for IR radiation;
- htey accumulate energy as collective vibrating states - eximoles, which can be transferred along thte molecule by means of dipole-dipole interaction;
- accumulated energy can be concentrated in a separate part of molecule, and it results in its modification: dissociation, electron excitement, etc.

Relation between excitement probability, accumulation and repartition of vibration energy in a molecule and intensity and frequency of internal radiation are analytically described. On this basis a method for the controlled modification of big molecules is developed. Theory of transformation of radiation from IR into visual light was also developed.

Scientists of the Division develop new radiopharmaceutical species. They developed a radiopharmacuetical preparation "Tallium chloride" intended for diagnostics of cardiac muscle state. SINP MSU obtained a license for production and realization of this preparation d.d. April 2, 1998. Currently the scientists conduct experiments with radiopharmaceutical species "Astat-211" - perspective direction of emitter radiotherapy of thyroid body cancer.

Within the frames of Geant4 (a software complex for Monte-Carlo simulation of radiation transfer in complicated biological objects) absorbed fractions in the target-organ of eye from all source-organs and reverse (eye - source-organ) were evaluated for gamma- and alfa-radiation of standard energies (gamma) na At-211 spectrum of alfa-lines. It is shown that for all organs, besides the organs situated near the head and the neck absorbed fractions are negligible. Evaluation of absorbed fractions in the target-organ of eye from the source-organ of brain for alfa-particles of At-211 spectrum energies has shown that these fractions are small. Libraries of low-energy processes are upgraded basing of the new published experimental data. A new possibiity of selection between mathemateical phantom of the human (MIRD model) and tomographic phantom (ORNL anatomic model) is added to the software. ORNL model is primarily tested for gamma-radiation.