Neutron induced reactions for the s process, and the case of Fe and Ni isotopes

Abstract

<p>Neutron capture cross sections are the key nuclear physics input to understand nucleosynthesis of the slow neutron capture process (<i>s</i> process). At the neutron time of flight facility n_TOF at CERN neutron capture cross sections of astrophysical interest are measured over a wide energy range. A measurement campaign to determine the stellar (n,γ) cross sections of Fe and Ni isotopes is currently being pursued. First results on the stellar cross section of #^{62}Ni(n,γ) confirm previous experimental results. The cross section of the radioactive <i>s</i>-process branching #^{63}Ni was measured for the first time at stellar energies and is about a factor of 2 higher than theoretical predictions. Future facilities and upgrades will allow to access a number of other radioactive nuclides which are crucial for understanding physical conditions of <i>s</i>-process environments.</p>