Light Radioactive Nuclei Interaction with Heavy Nuclei
The Study of the Total Interaction Cross Sections of Light Radioactive Nuclei with Nuclei of Lead, Uranium and Plutonium
Tech Area / Field
- PHY-ANU/Atomic and Nuclear Physics/Physics
3 Approved without Funding
Joint Institute of Nuclear Research, Russia, Moscow reg., Dubna
- VNIIEF, Russia, N. Novgorod reg., Sarov
- Grand Accélérateur National d'Ions Lourds, France, Caen
Project summaryThe aim of the Project is to measure the total interaction cross sections of accelerated beams of light radioactive nuclei having unusual neutron and proton density distributions (neutron and proton halo) with deformed nuclei of transuranium elements.
The large excess of neutrons or protons in such nuclei as 6He, 8He, 8B, 11Li, 12B results in their unusual spatial distribution, which is to manifest itself in the long-range component of nuclear forces, which in its turn is to cause the total cross sections of the nuclear reactions to increase as compared to the interaction cross sections of those nuclei with stable bombarding nuclei (4He, 7Li, 10B).
More detailed information on the long-range component of nuclear forces is obtainable not only from research on the structure of exotic nuclei but also from nuclear reactions at deep subbarrier energies, fission reactions being the most effective reactions owing to their high sensitivity, connected with the high-efficiency registration of fragments. Information of this kind is of crucial importance for the understanding of nuclear interactions at extremely low energies, which is observed in thermonuclear reactions, cold fusion and the production of nuclei in nucleosynthesis. The question remains totally open what concerns the interaction of nuclei with a proton halo (for example 8B) with other nuclei. This issue is of great importance not only for fundamental nuclear physics but also for astrophysics, which deals with nucleosynthesis and the related process of particle production (for example neutrinos) in the universe. Intense beams of radioactive nuclei will permit a different approach to the problem of transmutation, making it possible for long-lived radioactive nuclei to reach the valley of stability in a shorter time owing to the higher fusion and fission cross sections characteristic of the interactions of radioactive transuranium nuclei with the nuclei of secondary beams.
In carrying out the project, scientific and engineering approaches and techniques will be used that were developed at VNIIEF and JINR. Among these are: the high level of technology for producing targets of separated isotopes of transuranium elements and separated isotopes of lead at VNIIEF and JINR unique setups – cyclotrons with intense beams of heavy ions, magnetic analyzers of reaction products and multidetector systems for registration of reaction products. Such a combination of conditions as well as the joint effort of personnel from both science centers will permit successfully carrying out the project tasks.
The project involves the following tasks:
– High purification of separated isotopes of Pb, U and Pu from inert and radioactive impurities (VNIIEF).
– Development of techniques for producing and checking the thickness of radiation-resistant target backings (VNIIEF).
– Production of intense beams of light radioactive nuclei of 6He, 8He, 7Be, 8B, 9Li etc on the MTS-400 cyclotron and development of techniques for beam diagnostics (FLNR, JINR).
– Choice of techniques for measuring the total cross sections of the reactions, fusion and fission reactions of light radioactive nuclei with nuclei of isotopes of Pb, U and Pu (FLNR, JINR).
– Measurement of the total cross sections of the reactions, fusion and fission reactions of light radioactive nuclei with nuclei of isotopes of lead, uranium and plutonium (FLNR, JINR).
True interest has been expressed in favour of the proposed investigations by a number of foreign science centers. Among them is the French National Center GANIL (Caen), where a complex for accelerating intense beams of radioactive nuclei (the SPIRAL project) is soon to be commissioned. This center is basically concerned with research on the properties and structure of nuclei on the nucleon-drip lines. GANIL scientists are interested in collaboration with JINR and VNIIEF and willing to provide support for collaborative research considering that some of the equipment to be developed within the framework of the project can be applied in the SPIRAL project.