Stellar neutron capture rates and the s process

Neutron reactions are responsible for the formation of the elements heavier than iron. The corresponding scenarios relate to helium burning in Red Giant stars (s process) and to supernova explosions (r and p processes). The s process, which operates in or near the valley of β-stability, has produced about half of the elemental abundances between Fe and Bi. Accurate (n, γ) cross sections are the essential input for s process studies, because they determine the abundances produced by that process. The s-abundance patterns found in solar system material or in presolar grains provide important constraints for the physical conditions at the stellar sites of the s process. The experimental methods for the determination of stellar (n, γ) rates are outlined at the example of recent cross section measurements and the remaining quests will be discussed in the light of present possibilities and future developments