Institut für Strahlenphysik, University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
The key reaction 12C(α,γ)16O is taken as example and illustration for research on extremely slow and complicated reactions of astrophysical interest. Two sensitive experiments in the energy range Ec.m. = 890-2800 keV have been performed and the extrapolation to 300 keV of the S-factors obtained by an R-matrix analysis are SE1300 =(77 ± 17)keV b; SE2300=(81±22)keV b; Stot300 = (162 ± 40) keV b. The astrophysical reaction rate has been determined with ±25% precision in the temperature range 0.001 ≤T9≤10. From 30 years of research on this reaction, some problems related to experimental nuclear astrophysics become evident and suggestions for improving future works are made.
(Online publication July 12 2004)