Investigation of elastic scattering reactions with radioactive ion beam.

Abstract

This project consists in the investigation of the nuclear structure of neutron and proton rich light nuclei by direct reactions. Neutron and Proton rich light nuclei such as 6,8He, 8,9,11Li, 11Be, 12,13B and the isotopes 14,15C area radioactive with lifetime around tens to hundreds mili seconds. Some of them exhibits exotic properties and are called exotic nuclei. The possibility of producing radioactive beams out of these nuclei offers new and unique opportunities for research in nuclear physics. We can study and investigate the limit of the existence of nuclear matter, shell model, new quantum states in exotic nuclei. Reactions induced by exotic nuclei are particularly interesting to study the relationship between nuclear structure and reactions mechanism. For the astrophysics point of view, neutron and proton rich light nuclei play major role in several astrophysics environment. They are present in the possible inhomogeneous evolution of the early universe, in explosives r- and rp-processes, in the evolution of massive stars with low metalicity and in red giant stars, as well as in the acreting stars of a binary system with high flux of hydrogen. Thus, understand the effect of the structure of these nuclei on the elastic scattering and on the total reactions cross section may be important to understand these process. In particular, we are interested in investigating the structure of neutron-rich and proton rich carbon isotopes 10C, 14C and 15C by measurements of elastic scattering. Elastic scattering induced by loosely bound nuclei can be considered a powerful tool to investigate nuclear structure since it can reveal unusual features in nuclei such as extended halos or neutron skins. Some of these features affects the competing mechanism on the elastic scattering and coupled-channel analysis would be required to describe the cross sections. This work will be divided in two stages. In the first stage the proponent will work on developing new radioactive neutron-rich and proton-rich beams with the RIBRAS system (Radioactive Ion Beams in Brasil), among them, radioactive carbon isotopes, 10C, 14C and 15C and 13B. The following stage is then investigate direct reactions, elastic and inelastic scattering, induced by some of these beams. The plan is to measure angular distributions for the elastic scattering of 10C, 14C and 15C in 58Ni target. The description of the cross sections for elastic scattering is very sensitive to the interaction potential between the projectile and target nuclei and the structure of the nuclei involved. Thus, with these measurements, informations on the radius, density and cluster configuration, coupling to the continuum through the breakup channels will be investigated. These measurements will be part of a systematic study that we are conducting on direct reactions induced by radioactive beams.