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Nuclear Level Density Studies

#1049


Level Density Studies Based on Measurements of Evaporation Spectra and Cross-Section Fluctuations in Nuclear Reactions

Tech Area / Field

  • PHY-ANU/Atomic and Nuclear Physics/Physics

Status
3 Approved without Funding

Registration date
28.07.1997

Leading Institute
FEI (IPPE), Russia, Kaluga reg., Obninsk

Project summary

Purpose of the Project is the study of the nuclear level density in the mass number region of 40 < A < 70 on the basis of precise measurements of the neutron emission spectra and cross-section fluctuations in (p, n)-reactions, the neutron spectra in reactions, induced by ions of carbon and oxygen, and the development of consistent microscopic and phenomenological descriptions of statistical properties of excited nuclei. Experimental and theoretical research will be carried out into the framework of a collaboration between the Institute of Physics and Power Engineering (Russia) and the Ohio University (USA).

Main directions of the Project


a) Measurements of the double-differential neutron emission cross-sections and the fluctuations of excitation functions of discrete levels in (p, n) reactions on isotopes of Ti, Cr, Fe, Ni and in carbon and oxygen ions induced reactions on nuclei from Al to Cr by the time-of-flight method on pulsed beams of the tandem-electrostatic accelerators in the Institute of Physics and Power Engineering and the Ohio University.
b) Analysis of measured data in terms of the Hauser-Feshbach formalism and Ericson fluctuation theory to determine the absolute values and energy and spin dependencies of the nuclear level density for a wide range of excitation energies and angular momenta.
c) The creation of the consistent microscopic description and phenomenological systematics of nuclear level densities for medium mass nuclei.

Expected results

The following data will be obtained as the result of works on the Project:


a) Measurements of the double-differential neutron emission cross-sections in (p, n) reactions on the selected isotopes of Ti, Cr, Fe, Ni at the proton energies from 6 MeV to 10 MeV and evaluation from these data the corresponding nuclear level densities at excitation energies up to 8 MeV.
b) Measurements of the energy fluctuations of the excitation functions of discrete levels with a high resolution on the 30 m flight-path in (p, n) reactions on isotopes of Ti, Cr, Fe, Ni and evaluation from these data the corresponding nuclear level densities for excitation energies above 10 MeV.
c) Measurements of the double-differential neutron emission cross-sections in carbon and oxygen ions induced reactions on targets from Al to Cr and evaluation from these data the corresponding nuclear level densities at high excitation energies and high spins.
d) Microscopic calculations of the level densities for medium mass nuclei on the basis of the shell model approach and various parameterization of effective residual interactions.
e) Consistent phenomenological systematics of the nuclear level density parameters for medium mass nuclei convenient for the statistical calculations of various nuclear reaction cross-sections.

Scientific significance and commercial efficiency

The nuclear level density is the major statistical characteristic of excited nuclei which determines an accuracy of theoretical calculations of a wide scope of nuclear reaction cross-sections. Statistical calculations form the basis of most evaluations of nuclear data required by the nuclear power technology, nuclear astrophysics, medical, space and many other applications of nuclear physics. More accurate knowledge of the nuclear data permits to avoid expensive uncertainties and mistakes on the initial stages of various nuclear designs.

Potential role of foreign collaborators

Experimental and theoretical research will be carried out in the framework of the collaboration between the Institute of Physics and Power Engineering (Russia) and Ohio University (USA). Investigations of the nuclear level density are carrying out also by many other nuclear centers: NDC ENEA (Italy), LANL (USA), CIAE (China), IRK University of Vienna (Austria), JAERI (Japan), IRMM (Belgium). The collaboration with any of these labs also as other interested organizations will be very useful for the successful development of the Project.


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