First Direct Measurement on ⁵⁶Ni(n,p) Reaction for Astrophysical Implication

For the increased interest on the impact of this newly proposed nu-p process in the search of an answer to the heavy element production puzzle in core-collapse supernovae, a direct (n,p) reaction measurement is planned with the radioactive ⁵⁶Ni (a half-life of 6 days) at Los Alamos Neutron Science Center (LANSCE). The radioactive ⁵⁶Ni will be produced at the Isotope Production Facility at LANL by irradiating 55-75 MeV protons with about 250 microA current on a ⁵⁹Co foil through the (p,4n) reaction channel. We are investigating the chemical separation procedure for achieving a pure Ni radioactive target with required uniformity for (n,p) reaction studies. For handling a highly radioactive target and performing nuclear reaction studies with charged particle detectors under high radiation, we are developing an optimized detection system using a GEANT simulation and in-beam background measurements at LANSCE. The progress on this effort and the outlook for upcoming LANSCE experiments will be presented.