Experimental study of α-fission fragment correlations in the 232Th(12C,αf) reaction

Inclusive and correlation spectra of alpha particles and fission fragments were measured for the 232Th+12C (85 MeV) reaction, with the aim of separating different mechanism contribution. At backward angles α emission can be explained for by the evaporation processes. At forward angles the most important contribution is given by the break-up-fusion process. Mass distributions for compound nuclei 244Cm (E*=58 MeV, ff coincidences), and 240Pu(E*=37 MeV, ffα coincidences) were obtained. In the case of 240Pu mass distribution has a shape different from those obtained in light ion reactions at the same excitation energy idicating the strong influence of the entrance channel. The dependence of the mass distribution shape on the α-particle energy is also examined. The weak dependence of this shape on the α particle energy seems to be a combined effect of the projectile α cluster structure and of the Q values of different contributing exit channels