Orateur
Description
Neutron-induced reaction cross sections of short-lived nuclei are essential for astrophysics and applications in nuclear technology. However, these cross sections are very difficult or impossible to measure due to the difficulty to produce and handle the necessary radioactive targets. We are developing a project that uses for the first time surrogate reactions in inverse kinematics at a heavy-ion storage ring. This allows one to measure all the de-excitation probabilities as a function of the excitation energy of the nuclei formed through the surrogate reaction with unrivaled precision and indirectly determine the aforementioned cross sections. In this talk, I will present our new methodology and the results of the two first surrogate-reaction experiments that we have performed at the ESR storage ring of the GSI/FAIR facility in Darmstadt, Germany. In these experiments we have achieved a significant breakthrough by measuring for the first time the fission, gamma-ray, neutron and even two- and three-neutron emission probabilities simultaneously. The measurement of all competing decay channels sets significant constraints on fundamental quantities, including fission barriers, particle transmission coefficients, gamma-ray strength functions, and nuclear level densities. These quantities are then employed to infer (n,f), (n,gamma), (n,n'), (n,2n), and (n,3n) cross sections.
