Direct measurements of cross section of astrophysical interest

Abstract

New direct experimental methods and techniques, combined with the development of new theoretical tools have opened new avenues to explore nuclear reactions of significance for nucleosynthesis at or near the actual temperatures of stellar burning. The main difficulty of direct measurements is determined by the background, which, together with the low cross sections, set a limit on the energy range that can be investigated with a simple setup on the earth's surface. Essentially there are three sources of background, cosmic rays, environmental radioactivity and beam-target induced nuclear reactions. Each of these sources produces background of a different nature and energy, so that each reaction studied needs special care to suppress the relevant background component. I will show different experimental approaches that have been used to study processes of astrophysical interest. In particular, I will focus my attention on underground experiments and the recoil mass separator approach.