Seminarium Fizyki Jądra Atomowego

The elastic scattering of protons with stable and exotic light nuclei - helium, lithium and beryllium isotopes (4,6,8He, 6,7,9,11Li, and 9,10,11,12Be) were studied by means of the optical model (OM) with partial-wave expansion method in order to calculate the scattering observables (angular distributions for elastic scattering cross sections and analyzing powers, reaction cross sections) at a wide range of energies, starting from a few MeV/nucleon up to 200 MeV/nucleon. The optical potential (OP) is constructed from the single-folding potential using microscopic densities with M3Y nucleon-nucleon (NN) interaction for the real part and the NN-scattering amplitude of the high energy approximation for the imaginary one. The surface term of the OP is found to be important to fit the data of the exotic nuclei scattering indicating the possibility of breakup. The OM analysis reproduces well the basic scattering observables at energies up to100 MeV/nucleon. For higher energies, the eikonal approximation based on Glauber model gives results better than OM calculations. Similar behaviors for the volume integrals are found for all the scattering reactions. They are parameterized as functions of energy and used to construct a local energy-dependent microscopic OPs with no free fitting parameters. This local OP can be used to predict the cross-section data at energies at which no data exist. This work is extended to include the isoscalar and isovector contributions of NN interaction and the microscopic complex spin-orbit OP taken within Breiva-Rook approximation. This is used to analyze the proton elastic scattering from 9Be nucleus with incident energies up to 1000 MeV/nucleon. It succeeded to reproduce the cross-section data when a large surface contribution to the imaginary OP at high energies was included.

kontakt: urban@fuw.edu.pl