Reaction cross sections forC12+C12

Abstract

The yields of the eleven most abundant nuclides produced in the $^{12}\mathrm{C}$ + $^{12}\mathrm{C}$ reaction were determined in the energy range from 14-31 MeV (c.m.) via $\ensuremath{\gamma}$-ray techniques. Several reaction channels, including a few which involve only light-particle emission, show strong structure. Some of these anomalies are very narrow, having widths \ensuremath{\lesssim} 250 keV (c.m.). The $3\ensuremath{\alpha}$ evaporation cross section, as well as the yield of $^{12}\mathrm{C}$ via direct inelastic scattering, is determined. Further information is presented on the nature of a process leading to anomalously large $\ensuremath{\alpha}$-particle yields from the $^{12}\mathrm{C}$ + $^{12}\mathrm{C}$ reaction at low energies. The strong gross-structure features of the fusion and total reaction cross sections are discussed in the context of the optical model, and also with reference to the limiting angular momentum for fusion. The latter analysis leads to some insight into the origin of the gross structure, but also suggests a striking correlation between the fusion cross section and the extended ground state band of $^{24}\mathrm{Mg}$ at high energies. This correlation, if it is not coincidental, has interesting consequences with regard to the behavior of $^{24}\mathrm{Mg}$ at high angular momentum and energy.NUCLEAR REACTIONS Complete fusion, $^{12}\mathrm{C}$+$^{12}\mathrm{C}$, ${E}_{\mathrm{c}.\mathrm{m}.}=14\ensuremath{-}31$ MeV, measured $\ensuremath{\sigma}(E)$ for production of 11 nuclides; $\ensuremath{\gamma}$ measurement, Ge(Li) detectors and natural target; deduced total fusion, $3\ensuremath{\alpha}$ evaporation, and direct inelastic scattering $\ensuremath{\sigma}$; deduced limiting angular momenta for fusion; discussed anomalous $\ensuremath{\alpha}$-particle yield from $^{12}\mathrm{C}$ + $^{12}\mathrm{C}$ at low energies.