Systematic analysis of above-barrier fusion of Be9,10,11+Bi209

Measurements of fusion for Be9,10,11 allow testing of the relative importance to fusion and breakup of the α-cluster structure found in all these Be isotopes, compared with the neutron-halo structure only present for Be11. However, disagreements exist among different published experimental data sets for the reactions of Be9,10,11 with Bi209. Accurate measurements of above-barrier cross sections for the products of complete fusion (fission and evaporation residues) in the reaction of Be9 with Bi209 and Pb208 provide the basis for a reanalysis of above-barrier fusion for Be10,11+Bi209. This includes procedures making full use of the higher precision stable beam data and resolves many of the disagreements. The improved self-consistency of the analysis allows investigation of the experimental average fusion barriers. Although showing some scatter, these suggest a higher barrier for the neutron halo nucleus Be11. Comparison of published cross sections for fusion associated with capture of all the charge of the projectile suggest that all these Be isotopes show significant suppression of complete fusion, a surprising result given that the α-breakup threshold energies are 1.57MeV for Be9 but over 7MeV for Be10,11. Further experimental studies to investigate in more detail the division between complete and incomplete fusion for reactions of Be10,11 are needed.