FUNDAMENTAL RESEARCHES IN THE FIELD OF HADRON-NUCLEAR AND NUCLEUS-NUCLEAR INTERACTIONS

• d.p.-m.s. Varentsov Victor Livovich
• c.p.-m.s. Mourin Yuriy Andreevich

In the recent years general working programs have been related to the following fundamental and applied problems.

1. Experimental and theoretical studies of nuclear processes under high and intermediate energies of elementary particles and nuclei.
2. The study of nuclear multifragmentation and isoscaling, search for phase transitions within the systems with limited number of component particles, analysis of baryon matter status equation.
3. Continuation of the program of tests and first experiments on 3π -device CHICSi (Uppsala).
   • An effect of isoscaling is determined (scale-invariant properties of isotopic relations) in fragmentation processes under an effect of protons and light ions, and a role of charge-symmetric member in nuclear status equation is subjected to analysis. The effect of isoscaling can be explained as a result of static character of fragments generated in reactions. Hydrodynamic model of relativistic heavy nuclei interaction is subjected to further developing; sub-threshold generation of kaons and antiprotons is studied, as well as nuclear medium effects under nucleus-nuclear collisions. With the purpose to get information about properties of hadrons in nuclear environment they conducted experimental study of pion excitation function in energy range from absolute threshold to 500 MeV in reactions caused by protons and nuclei.
4. Experimental and theoretical efforts to study characteristics of secondary products from nucleon-nuclear interactions (residual nuclei and heavy fragments) under intermediate energies in connection with the tasks to determine radiation exposure effects in microelectronics and under proton-ray treatment in medicine.
   • Preparation is made to inverse travel time experiments on accumulating acceleration installation CELSIUS destined to study the processes of residual nuclei and heavy fragments generation in reactions initiated in silicon nuclei with the purpose to get information required for evaluation of radiation effects in silicon. The reactions are modeled for intermediate energies, and prime experiments are carried out on heavy ion beams and hydrogen target.
5. The study of processes of heavy ion (U, Kr, Ar, 0) interaction with solid-state targets within 200-400 MeV/nucleon energy range. Design and creation of systems to cool ionic beams of radioactive nuclei in high-pressure gas streams. The research in dynamics of energy transfer by heavy ion beam in solid targets.
   • There have been conducted studies related to creation of cooling systems for radioactive ion beams, to be used in international collaboration Project SHIPTRAP and in design of Munich accelerator of fission fragments (MAFF). The new method "fair-wind gas cell" to cool intensive low-energy ionic beams was fist proposed here. With the purpose to simulate the processes of beam forming in ultrasonic gas streams there were developed mathematical models and computer codes. New results were obtained with the help of a new-type compact non-magnetic spectrometer in the study of processes of interaction between accelerated heavy ions of ²³⁸U, ⁸⁶лЗ, ⁴⁰бЗ ¹⁸п within 200-400-MeV/nucleon energy range with solid-state targets.