Effect of non- α -cluster projectile on incomplete-fusion dynamics: Experimental study of the N14+Ta181 system

Abstract

In order to study incomplete fusion (ICF) reaction dynamics, the present work manifests the role of a non-$\alpha$-cluster ${}^{14}\mathrm{N}$ projectile on ${}^{181}\mathrm{Ta}$ target at energies $\approx \mathrm{4–7}$ MeV/nucleon using the offline $\gamma$-ray spectroscopy. The excitation functions for 15 reaction residues populated in ${}^{14}\mathrm{N}+{}^{181}\mathrm{Ta}$ system have been measured and analyzed within the framework of statistical model code PACE4. The experimentally measured excitation functions of evaporation residues populated via xn/pxn channels are found to be well reproduced by the predictions of code PACE4, which confirms their production solely via complete fusion process. However, an enhancement in the measured excitation function as compared to PACE4 calculations, particularly in tail portion of ${}^{192}\mathrm{Hg}$ residue ($3n$ channel) has been observed indicating the presence of precompound emission. A significant contribution from precursor decay in pxn channels has also been observed. An enhancement in the measured excitation functions for $\alpha$-emitting channels as compared to the PACE4 predictions has been observed and attributed to the incomplete fusion process. Further, the contribution from incomplete fusion process in the ${}^{14}\mathrm{N}+{}^{181}\mathrm{Ta}$ system has also been deduced in terms of strength function ($F_{\mathrm{ICF}}$). The results have been discussed in terms of the parameters which influence the dynamics of ICF process. The $F_{\mathrm{ICF}}$ is found to depend strongly on projectile energies, the product of projectile and target charges, and $\alpha -Q$ value of the projectile.