Neutron Reactions in Astrophysics: The Role of New Facilities and Improved Laboratory Approaches

Abstract

The abundance of elements between Fe and the actinides have essentially all been produced by neutron reactions, either by the slow neutron capture process during helium burning in red giant stars (s process) or by explosive nucleosynthesis, e.g. in supernovae (r and p process). Laboratory studies have so far concentrated on the s process, which operates in or near the valley of β-stability. Under these conditions laboratory results are of direct impact for the interpretation of the observed abundance patterns and their role as crucial tests for stellar evolution models. The high flux at spallation neutron sources allows one to investigate numerous difficult and hitherto inaccessible cases, including the cross sections of important radioactive nuclei.