Interaction Cross Sections and Neutron Skin Thicknesses of Ni Isotope Chain

The equation of state of nuclear matter(EOS), which describes the macroscopic properties of nuclei, is essential not only to describe the structure and collisions of nuclei but also to understand the scale of supernova explosions and the structure of neutron stars. Since nuclear matter is composed of two Fermi particles, protons and neutrons, the equation of state has a term that depends on the density difference between the two, which is called the symmetry energy. From previous studies, it is known that the first-order density dependence of the symmetry energy is closely related to the thickness of the neutron skin. [1]

In this study, interaction cross sections for ^58-77Ni on a carbon target at 260 MeV/nucleon have been measured at the Radioactive Isotope Beam Factory(RIBF) at RIKEN by using the BigRIPS fragment separator. The present data are the first systematic ones along the isotopic chain in Ni mass region.

In this presentation, we’ll report the matter radii derived from the experimental results using Glauber calculation and compare them with known charge radii. Also, we’ll discuss the neutron skin thickness of Ni isotopes, which is obtained by the present data combined with known charge radii.

[1] M. Centelles et al., Phys. Rev. Lett. 102 (2009) 122502.