A technique for studying (n,p) reactions of astrophysical interest using radioactive beams with SECAR

The formation of nuclei in slightly proton-rich regions of the neutrino-driven wind of core-collapse supernovae could be attributed to the neutrino-p process (nu p-process). As it proceeds via a sequence of (p,gamma) and (n,p) reactions, it may produce elements in the range of Ni and Sn, considering adequate conditions. Recent studies identify a number of decisive (n,p) reactions that control the efficiency of the nu p-process. The study of one such (n,p) reaction via the measurement of the reverse (p,n) in inverse kinematics was performed with SECAR at NSCL/FRIB. Proton-induced reaction measurements, especially at the mass region of interest, are notably difficult since the recoils have nearly identical masses as the unreacted projectiles. Such measurements are feasible with the adequate separation level achieved with SECAR, and the in-coincidence neutron detection. Adjustments of the SECAR system for the first (p,n) reaction measurement included the development of new ion beam optics, and the installation of the neutron detection system. The aforementioned developments along with a discussion on the preliminary results of the p(Fe-58,n)Co-58 reaction measurement are presented.

Automated summary

The formation of nuclei in slightly proton-rich regions of neutrino-driven wind in core-collapse supernovae can be explained by the neutrino-p process (nu p-process). Recent studies have identified key (n,p) reactions that control the efficiency of the nu p-process. Measurement of a (n,p) reaction in inverse kinematics was performed with SECAR at NSCL/FRIB, which is difficult due to the nearly identical masses of recoils and unreacted projectiles. The development of new ion beam optics and the installation of a neutron detection system were necessary for this measurement.