Study of incomplete fusion reaction dynamics for the system ¹⁴N + ¹⁶⁹Tm using the forward Recoil Range distribution technique

Abstract

Studies in the past have demonstrated that complete fusion and incomplete fusion dynamics are both significant just above the Coulomb barrier, yet the dynamics of incomplete fusion are elusive since they are so complex below 10 MeV/nucleon. In order to investigate low-energy incomplete fusion dynamics, we measured the forward recoil range distribution of evaporation residues populated in the system 14N + 169Tm at energy ≈ 5.9 MeV/nucleon. A stack target-catcher activation technique followed by offline-γ- spectroscopy was used to estimate the forward recoil range distribution of the evaporation residues. In order to investigate a new parameter for describing incomplete fusion dynamics, the incomplete fusion fraction (FICF (%)) for the present system was estimated from the range-integrated cross-sections and compared with other systems in the literature. The forward recoil range distribution and range integrated cross-sections of seven evaporation residues have been estimated experimentally. These cross-section results agree well with the experimental results obtained from the excitation functions. On re-investigation of entrance channel systematics for Qα value of projectile, mass-asymmetry (µMA), and Coulomb factor (ZP ZT ), it has been found that the Qα-value systematic for 14N is not valid at all projectile energies. The forward recoil range distribution measurement is one of the direct methods available to probe the complete and incomplete fusion contributions in evaporation residues at low projectile energy. It has also been observed that the dynamics of ICF are not only dependent on the parameters of one entrance channel but on multiple entrance channels. We have also introduced the entrance channel parameter Zeta (ζ) for the first time in Incomplete Fusion reactions to see the combined effect of mass-asymmetry (µMA) and ZP ZT, as this parameter is better suited than µMA and ZP ZT individually and has a linear dependency on FICF (%).