Experimental study of cross sections in theC12+Al27system at≈3–7MeV/nucleonrelevant to the incomplete fusion process

Abstract

Background: The reaction mechanism in the low mass region particularly at low projectile energies in heavy-ion fusion processes has not been fully understood. More and more experimental data on fusion processes are required for the accurate description of reaction processes involved at low projectile energies. In the literature, cross section data for the fusion process using a $^{12}\mathrm{C}$ beam in the lower mass region and at low projectile energies are scarce.Purpose: To understand the dynamics of fusion processes and to test various existing theoretical models, the measurements of reaction cross sections in the $^{12}\mathrm{C}+^{27}\mathrm{Al}$ system have been carried out.Method: The experiments were performed for the measurement of the cross sections for the residues produced in the interaction of the $^{12}\mathrm{C}$ ion with a $^{27}\mathrm{Al}$ target nucleus at 20 different energies covering the energy range from $\ensuremath{\approx}39$ to $85\phantom{\rule{0.28em}{0ex}}\mathrm{MeV}$. The off-line $\ensuremath{\gamma}\ensuremath{-}\text{ray}$ spectrometry based activation technique has been used to measure the cross sections.Results: The measured excitation functions were compared to those evaluated with the code pace4 based on the statistical approach and Monte Carlo procedure. The enhancement of experimental cross sections as compared to the theoretical predictions of code pace4 has been observed. The SUMRULE model predictions indicate that incomplete fusion processes are associated with smaller values of the angular momenta than that of its critical value required for complete fusion processes.Conclusions: In the lower mass region, phenomena such as incomplete fusion and direct reaction processes are of importance even at energies as low as $\ensuremath{\approx}3--7\phantom{\rule{0.28em}{0ex}}\mathrm{MeV}/\text{nucleon}$, where fusion evaporation channels are expected to be dominant.