Reaction data in helium and carbon burning

Nuclear fusion reactions play a key role in the understanding of energy production, nucleosynthesis of the elements in stars and the evolution of massive stars. Therefore, the direct determination of the cross section of these reactions at the relevant thermal energies is of utmost importance, but usually hampered by cosmic radiation, beam-induced background and many other experimental problems. A status report on the experimental situation of two key reactions, C-12(alpha,gamma)O-16 and the C-12 + C-12 fusion reactions, is given in this paper.