Preparation of the SECAR system for the first (p,n) reaction measurement.*

     Neutron-induced reactions are essential to the nucleosynthesis of the elements heavier than iron. Recent studies show that key (n,p) reactions, such as the ⁵⁶Ni(n,p)⁵⁶Co and ⁶⁴Ge(n,p)⁶⁴Ga, regulate the efficiency of the so-called neutrino-p process (νp-process), which is responsible for the formation of elements between nickel (Ni) and tin (Sn) in type II supernovae. Nucleosynthesis in νp-process occurs at slightly proton-rich regions in the neutrino-driven wind of core-collapse supernovae, via a sequence of proton-capture reactions and (n,p) reactions. The small abundance of neutrons needed originates from anti-neutrino captures on free protons.

     The recoil mass separator, SECAR (SEparator for CApture Reactions) at FRIB, has been initially designed with the required sensitivity to study (p,γ) and (a,γ) reactions, directly at astrophysical energies in inverse kinematics, with radioactive beams of masses up to about A = 65. However, SECAR is also suitable for the study of (n,p) reactions via measuring the reverse (p,n) reactions in inverse kinematics. Such proton-induced reactions are particularly challenging since the recoils and the unreacted projectiles have nearly identical momenta. The SECAR system with its sequence of multipole magnets along with two Wien Filters could possibly overcome such challenges, with the development of alternative ion beam optics, and the implementation of coincidence detection of neutron-recoil pairs. In this talk, the preparation of the SECAR system to accommodate its first (p,n) reaction measurement will be discussed.