Author/Authors :
T. Hartmann، نويسنده , , S. Volz، نويسنده , , M. Babilon، نويسنده , , P. Mohr، نويسنده , , Peter K. Vogt، نويسنده , , A. Zilges، نويسنده ,
Abstract :
Recently the importance of small contributions of electric dipole strength near the particle threshold to the production rates of atomic nuclei has become evident. Prior estimates concentrated on the Giant Dipole Resonance (GDR) which dominates photoabsorption in all nuclei. Extrapolations to smaller excitation energies were assumed to be sufficiently reliable. However, new measurements reveal that collective E1 strength can be found in the threshold region.