Broad structures in γ-ray multiplicity gated p and α spectra in low energy 12C+93Nb and 16O+89Y reactions

Gamma ray multiplicity gated proton spectra have been measured in the reactions 12C+93Nb at E(12C)= 40 and 45.5 MeV and 16O+89Y at E(16O)= 51 and 54 MeV populating the CN 105 Ag at EX between 35 and 40 MeV. Broad structures are seen in all spectra at high gamma ray multiplicities. The present data, along with those from our earlier work on the former reaction at E(12C)= 42.5 MeV, establish the compound nuclear origin of the structures. The data can be explained by incorporating a localised enhancement of nuclear level density in the excitation energy and angular momentum space. Multiplicity gated Îś spectra have also been measured in the same reaction at E(12C)= 37.5 – 45 MeV. Broad structures seen in these spectra seem to have contribution from other reaction mechanisms also

Investigation of the threshold anomaly in the near-barrier elastic scattering of

Elastic-scattering angular distributions of 7Li on 116Sn have been measured at different bombarding energies between 18 to 35 MeV. The effects of the weakly bound projectile breakup channel on the bombarding energy dependence of the interaction potential have been investigated. In this work we present the experimental results, along with the theoretical analysis using Woods-Saxon potential to investigate the energy dependence of the interacting polarizing potentials. Total reaction cross-sections are also presented and discussed

Competing asymmetric fusion-fission and quasifission in neutron-deficient sub-lead nuclei

International audienceTo disentangle the role of shell effects and dynamics, fission fragment mass distributions of 191 Au, a nucleus in the newly identified island of mass asymmetric fission in the sub-lead region, have been measured down to excitation energy of ≈20 MeV above the fission barrier via two different entrance channels, viz. 16 O+ 175 Lu and 37 Cl+ 154 Sm reactions. Apart from having signature of the shell effects in both the cases, clear experimental evidence of quasifission has been observed in the mass distributions of the Cl induced reaction, that has also been substantiated by the theoretical calculations. This crucial evidence along with a systematic analysis of the available experimental data has revealed that the dynamics in the entrance channel has significant influence on most of the reactions used earlier to explore the persistence of recently discovered mass asymmetry in β -delayed fission at low energy in this mass region, ignoring which might lead to ambiguity in interpreting the heavy-ion data

Conclusive evidence of quasifission in heavy-ion induced reactions in neutron-deficient sub-lead nuclei exhibiting asymmetric fission

Fission fragment mass distributions of 191Au, a nucleus in the newly identified island of mass asymmetric fission in the sub-lead region, have been measured down to excitation energy of ~ 20 MeV above the fission barrier via two different entrance channels, viz. 16O+ 175Lu and 37Cl+ 154Sm reactions. Apart from having signature of the shell effects in both the cases, clear evidence of quasi-fission has been observed in the mass distributions of the Cl induced reaction. A systematic analysis of available experimental data reveals that the dynamics in the entrance channel has significant influence on most of the reactions used to study asymmetric fission in this region, ignoring which might lead to ambiguity