Coincidences between light particles, evaporation residues and complex fragments emitted in the reaction 58Ni+58Ni at 500 MeV bombarding energy

Light particles (protons and alphas) were measured in coincidence with complex fragments (4 40) using the large detector array HILI. A {sup 58}Ni beam of 500 MeV extracted from the HHIRF tandem accelerator was used to bombard a {sup 58}Ni target of 99% enrichment. A good account of the proton and alpha spectra in coincidences with the residues can be achieved only by including in the statistical model calculation the emission of complex fragments and allowing a small emission of a dinuclear configuration formed prior to fusion. The relative kinetic energy spectra between the complex fragments and the residues show a typical Coulomb peak consistent with emission from the compound nucleus and the out of plane angular correlation shows that the emission is coplanar

Crystal blocking measurements of the time delay of fission induced by S, Ti and Ni borbardment of W

The time delay in fission induced by bombardment of W with 180 MeV 32S, 240\u2013255 MeV 48Ti, and 315\u2013375 MeV 58Ni has been measured by observation of crystal blocking. There is a clear narrowing and a small increase in the minimum yield of the angular dips for fission compared with scaled dips for elastically scattered ions. This is interpreted as a fission delay of about 2 as, only weakly dependent on energy and atomic number. The delay is longer by 1 to 2 orders of magnitude than obtained from standard interpretations of measurements of prescission neutrons and giant-dipole-resonance gamma rays and from calculations of the nuclear dynamics in heavy-ion reactions