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Exotic Nuclei States

#1305


Investigation of the Exotic States of the Atomic Nuclei

Tech Area / Field

  • PHY-ANU/Atomic and Nuclear Physics/Physics

Status
3 Approved without Funding

Registration date
23.07.1998

Leading Institute
Joint Institute of Nuclear Research, Russia, Moscow reg., Dubna

Supporting institutes

  • VNIIEF, Russia, N. Novgorod reg., Sarov

Collaborators

  • Grand Accélérateur National d'Ions Lourds, France, Caen

Project summary

To exotic states of the nuclei there refer states with unusual properties. In the region of the light nuclei there are the nuclei with a large surplus of neutrons or protons, with new types of a decay. In the region of the heavy nuclei with a mass more than 180 to exotic states there refer many isomeric states of the form and angular moment. The research of exotic states will expand knowledge about the nuclear substance and properties of the nuclei and will promote their application in applied physics and engineering. The realization of the project will promote engaging physicists and engineering experts RFNC-VNIIEF in the research of problems of the newest nuclear physics.

The purposes of the project are synthesis and research of properties of the exotic light nuclei with masses less than 20 on a cyclotron U-400M (JINR) and electrostatic accelerator with recharge EGP-10 (RFNC-VNIIEF), and also isomeric states of the tantalum-180 nucleus and isotopes Am and Cm; the definition of charge radius and quadrupole moments of the nuclei in isomeric states with anomalous low excitation energy by methods resonance laser spectroscopy (JINR); development of technology of manufacturing thin polymeric especially proof to temperature and radiation damages backings for light nuclear targets at currents of a cyclotron beam up to 1 microampere; production a sample, enriched with an isotope of tantalum-180; development of technology and manufacture of tritium target with a high contents of tritium (RFNC-VNIIEF) for the use in work on a cyclotron of JINR at production of light neutron-rich nuclei.

The organizations-participants of the project apply advanced engineering methods for realization of the work:

RFNC-VNIIEF: the measurements of reaction cross sections on the light nuclei are fulfilled, basically, in a method of accumulation of beta activity in the pulse mode of a beam of the EGP-10 accelerator. When the half-lives of beta-activity in various channels are not distinctive, methods of detecting charged particles or gamma and neutrons of detection are applied. In the theoretical analysis of functions of excitation the theory of threshold phenomena is applied.

The research of low-lying levels of the Та-180 nucleus uses a method of excitation of levels on the beam of isotopes of hydrogen accelerated by EGP-10 up to an energy 12,5 MeV followed by a measurement of gamma-ray spectra by one or two gamma- detectors produced by decay of the nuclei from these levels.

The manufacture of the tritium target will be made by a method of saturation with tritium of a titanium stratum after its thermal activation and hydrogenation.

JINR: The study of isomeric states of isotopes Am and Cm with an excitation energy less than 1 keV will be made by methods of resonance laser spectroscopy with use of a system of transport of the investigated nuclei by a gas stream.

The technique, including the magnetic analyzer, semiconducting multilayer telescope and positional-sensitive proportional chamber, allows to identify the exotic light nuclei and to measure energy and angular distributions of yields of reactions, caused by these nuclei. The 6Не, 8В, 17Ne exotic nuclei will be investigated. On the beam of the exotic nuclei reactions of fusion, fragmentation and few-nucleonic transfer will be investigated.

In an outcome of realization of the project is expected to receive the following results: 1) to study a structure and properties of the exotic light nuclei on the boundary of nucleonic stability; to investigate processes of scattering, fusion and other on the beam of these nuclei; to receive more complete data on already open isotopes of the light exotic nuclei; 2) to study properties of isomeric states of tantalum-180 and Am and Cm isotopes; to determine physical parameters of these nuclei; 3) to make light nuclear layers and targets, including the tritium target for work on accelerators at manufacture of neutron-rich light nuclei; 4) to develop a technology on creation of a thin high-temperature polymeric backing for light nuclei targets; 5) to develop a technology of separation of tantalum isotopes and to make a target enriched by an isotope of tantalum-180.

The potential foreign collaborators role can consist: 1) in joint study of problems; 2) putting at each others temporal use of enriched targets and equipment; 3) in interchange of ideas and information, making connections with other science centers and scientists.


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