Modular apparatus for nuclear reactions spectroscopy (MARS): characterization and first application to determine \(^{12}\)C(\(^6\)Li,\(^4\)He)\(^{14}\hbox {N}^{g.s}\) nuclear reaction cross sections

Abstract

This work presents MARS (Modular apparatus for nuclear reactions spectroscopy) and its characterization prior to its first application to measure \(^6\)Li+\(^{12}\)C nuclear reactions. Measurements were performed at the 3 MV tandem accelerator of the CNA (National Accelerator Center), in Seville, Spain. The \(^{6}\)Li projectiles were accelerated at energies around the \(^6\)Li+\(^{12}\)C Coulomb barrier (\(V^{\text {cm}}_{B}\sim 3.0\) MeV - center of mass and \(V^{\text {lab}}_{B}\sim 4.5\) MeV - laboratory frame). Using a \(^{6}\hbox {Li}^{2+}\) beam, we measured at 13 laboratory energies from 4.00 to 7.75 MeV. Thus, we present the excitation function of \(^{12}\)C(\(^6\)Li,\(^4\)He)\(^{14}\hbox {N}^{g.s.}\) reaction, at 2 backward angles (\(110.0^\circ \) and \(140.0^\circ \)). The projectile dissociation, leading to this reaction, increases with the bombarding energies around the Coulomb barrier. This dissociation is favored at an optimum energy \(E_{b}^{\text {op}}\) \(\ge \) \(V_{B}\) + \(|Q_{bu}|\), where \(V_{B}\) is the Coulomb barrier of the system, and \(|Q_{bu}|\) is the module of Q-value for the \(^6\)Li dissociation into \(^4\)He+\(^2\)H. This result corroborates a systematic analysis of weakly bound projectiles reacting on several targets [1].