An experiment was carried out to explore heavy ion incomplete fusion reaction dynamics, within the framework of the break-up fusion model, at energies near and above the Coulomb barrier. Excitation functions for several radionuclides produced via $\mathit{xn}$, $\mathit{pxn}$, and $\alpha \mathit{xn}$ channels were measured in the ${}^{16}\mathrm{O}+{}^{181}\mathrm{Ta}$ system at energies of $\approx 76\text{−}100$ MeV. The experimental excitation functions were compared with those calculated using the theoretical model code PACE4. It was observed that excitation functions of $\mathit{xn}/\mathit{pxn}$ channels are in good agreement with theoretical predictions. However, a significant enhancement in the measured excitation functions of $\alpha$-emitting channels was observed and attributed to the incomplete fusion processes. The incomplete fusion fraction ($F_{\mathrm{ICF}}$) that gives the relative importance of complete and incomplete fusion processes was found to increase with energy. The results are discussed in terms of $\alpha$-cluster structure of the projectile on various fusion reactions.

• Received 27 March 2009

DOI:https://doi.org/10.1103/PhysRevC.80.014601