Above-barrier cross sections of α-active heavy reaction products, as well as fission, were measured for the reactions of 10,11 B with 209 Bi. Detailed analysis showed that the heavy products include components from incomplete fusion as well as complete fusion (CF), but fission originates almost exclusively from CF. Compared with fusion calculations without breakup, the CF cross sections are suppressed by 15% for 10 B and 7% for 11 B. A consistent and systematic variation of the suppression of CF for reactions of the weakly bound nuclei 6,7 Li, 9 Be, 10,11 B on targets of 208 Pb and 209 Bi is found as a function of the breakup threshold energy.

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Comprehensive fission measurements, including mass-angle distributions, for the reaction of 32S with the prolate deformed nucleus 232Th at near-barrier energies show two distinct components in both mass and angle; surprisingly, both have characteristics of quasifission. Their relative probabilities vary rapidly with the ratio of the beam energy to the capture barrier, suggesting a relationship with deformation aligned (sub-barrier), or antialigned (above-barrier), configurations at contact.

Fission fragment mass-angle correlations and mass ratio distributions have been measured for the reactions 16 O + 186 Os, 24 Mg + 178 Hf, 34 S + 168 Er, and 48 Ti + 154 Sm, forming the 202 Po composite nucleus, at near barrier energies. Systematic analysis based on the expected dependence of the variance of the mass distribution on the angular momentum and temperature of the compound nucleus indicate that the two lighter systems evolve through true compound nucleus fission. Evidence of quasifission was observed for the two most mass-symmetric reactions, through strong mass-angle correlations for the 48 Ti + 154 Sm reaction and a broadened mass ratio distribution for the 34 S + 168 Er reaction. Furthermore, the increase in mass width at near barrier energies shows the influence of the alignment of statically deformed target nuclei.

Forming the same heavy compound nucleus with different isotopes of the projectile and target elements allows nuclear structure effects in the entrance channel (resulting in static deformation) and in the dinuclear system to be disentangled. Using three isotopes of Ti and W, forming 232Cm, with measurement spanning the capture barrier energies, alignment of the heavy prolate deformed nucleus is shown to be the main reason for the broadening of the mass distribution of the quasifission fragments as the beam energy is reduced. The complex, consistently evolving mass-angle correlations that are observed carry more information than the integrated mass or angular distributions, and should severely test models of quasifission.

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High precision measurements for back-angle quasi-elastic scattering of 16 O from various target nuclei have been made, and are compared with coupled channels calculations to determine the diffuseness of the real part of the Woods-Saxon nuclear potential. The extracted diffuseness parameters are in the range of 0.60 to 0.69 fm, and agree well with previous results using a 32 S projectile. The measured quasi-elastic energy spectra close to the barrier show both discrete peaks and a broad continuous structure with Q-values down to −25 MeV. These suggest the inadequacy of coupled channels calculations that include couplings only to low energy, discrete states of the colliding nuclei.