Observation of complete- and incomplete-fusion components in 159Tb , 169Tm ( 16O , x) reactions: Measurement and analysis of forward recoil ranges at E/A ≈ 5-6 MeV

Abstract

With a view to study complete- and incomplete-fusion components in 159Tb , 169Tm ( 16O , x reactions, experiments have been carried out at the Inter-University Accelerator Center, New Delhi, India using the 15UD Pelletron accelerator facilities. The forward mean recoil ranges for some radio-nuclides; 168m Lu , 167Lu , 167Yb , 166Tm produced in the 16O$ + $159Tb system at ≈ 90 MeV, and 179Re , 177Re , 177W , 178Ta and 177Hf produced in the 16O$ + $169Tm system at ≈ 87 MeV have been measured. The recoil-catcher activation technique followed by off-line γ -spectrometry has been employed in the present work. The analysis of forward mean ranges for different radio-nuclides has been done in the framework of the degree of linear momentum transfer from projectile to target nucleus by adopting break-up fusion model considerations. Different complete- and incomplete-fusion components, which may be attributed to the fusion of 16O and/or 12C and 8Be transfer from the 16O projectile to the target nucleus have been observed. An attempt has also been made to separate out the relative percentage contributions of complete- and incomplete-fusion components using experimentally measured forward recoil ranges. The complete-fusion contributions deduced from recoil range distribution are found to be consistent with the prediction of the theoretical model code PACE. The analysis of data indicates the complete- and incomplete-fusion competition for both the systems at the given energies.