Determining the Barrier Height of the ⁵⁴Cr+²⁰⁸Pb and ⁵⁴Cr+²⁴³Am Systems from Back-angle Quasi-elastic Scattering

Due to the extremely small reaction cross-sections and the short half-lives of superheavy nuclei, the experimental cycles are long, and the associated costs are high. Therefore, determining the optimal beam energy through theoretical studies and indirect experimental methods is an essential preliminary task. Back-angle quasi-elastic scattering, as a critical complement to fusion reactions, provides key Coulomb barrier information, offering valuable guidance for identifying the optimal incident energy for superheavy element synthesis. In this study, we constructed a detector array consisting of a gas ionization chamber and silicon detectors. The back-angle quasi-elastic scattering excitation function for the ⁵⁴Cr+²⁰⁸Pb reaction was measured, yielding an average barrier height of 206.27±0.62 MeV, which showed good consistency with existing experimental data. Additionally, we measured the back-angle quasi-elastic scattering experimental data for the ⁵⁴Cr+²⁴³Am reaction, with an average barrier height of 234.66±0.45 MeV. These results provide valuable references for future superheavy element synthesis, including the production of Z=119.