First EXL experiment with stored radioactive beam: Proton scattering on 56Ni

EXL (EXotic nuclei studied in Light-ion induced reactions at the NESR storage ring) is a project within NUSTAR at FAIR. It aims at investigations of light-ion induced direct reactions in inverse kinematics with radioactive ions cooled and stored in the future NESR (New Experimental Storage Ring). The existing ESR (Experimental Storage Ring) at GSI, together with its internal gas-jet target, provides a unique opportunity to perform such kind of experiments on a smaller scale at the present time. We have developed a UHV-compatible (Ultra High Vacuum) detector setup mainly based on DSSDs (Double-sided Silicon-Strip Detector) for the target-like recoils [4]. With this setup we were able to successfully investigate reactions with a stored radioactive beam for the first time ever. As a part of the first EXL campaign we investigated the reaction 56Ni(p,p)56Ni in inverse kinematics in order to measure the differential cross section for elastic proton scattering and deduce the nuclear-matter distribution and radius of 56Ni. In the following, the experimental setup is introduced in more detail, and the current status of the ongoing analysis is discussed.