Energy deposition and GDR emission in inelastic alpha particle scattering.

Neutron fold distributions measured for the reaction Bi-209(alpha,alpha') a t 240 MeV have been analyzed with the help of Statistical Model calculation s to determine the distribution of excitation energy in the primary target fragments as a function of the projectile energy loss, EL. Results show tha t the distributions in excitation energy feature a plateau which extends fr om the kinematical limit E-x=EL to very small excitations, suggesting a var iety of interactions of the beam particles with the target nucleus. Requiri ng an additional coincidence with a light charged particle leads to selecti on of a significant higher average excitation energy. This effect is extrap olated to explore results of previous GDR decay measurements in the case of a Pb-208 target. Corrections of derived GDR parameters due to the partial transfer of excitation energy are suggested.