Influence of weakly bound 9Be in fusion by comparing 9Be + 116Sn and 10B + 115In reactions

To search the signatures of break up channel of 9Be on fusion two reactions were so chosen that the same compound system 125Xe with the same excitation energy can be investigated with stable 19B beam and stable-but-weakly-bound 9Be beam as well. Energies were taken in the range 20-50 MeV. The on-line and off-line γ-measurements were made using HPGe detectors. The cross sections were calculated from the γ yields. The ratio of the sum of cross sections of all α channels to the sum of all ER's of the compound nucleus formed after complete fusion Rα was calculated for all energies for both the cases from the measured data. The PACE3 code, using statistical model was used to find the ratio of sum of cross sections of all α channels from evaporation to the cross section of compound nucleus formed after complete fusion rα for the energies of the experiment. The ratio rα is similar for both the cases at the matching excitation energies but different near the barrier. The Rα was, however, distinctly higher for the case of 9Be than for 10B. The observation that Rα for 10B was matching with rα leads to the conclusion that α emitting channels are populated in large fraction by incomplete fusion and in small fraction by complete fusion (governed by statistical model). This is clearly the break up channel effect on the fusion. (author)