Fission Decay Of Giant-Resonances In U-238 Excited In Alpha Scattering At Small Momentum-Transfer

Coincidences between inelastically scattered alpha-particles and fission products from U-238 have been measured with a 172 MeV a beam. Inelastically scattered alpha-particles were measured at angles between 0-degrees and 4-degrees. The fission decay of the giant resonances, in particular, of the giant quadrupole resonance, is clearly observed in the coincidence data. Experimental fission probabilities are well described within the statistical model. The multipole strength, extracted from the angular distribution, is consistent with that obtained from singles (alpha, alpha') measurements if a background due to multistep processes is taken into account.