Speaker
Description
Type I X-ray bursts are frequent transient events observed in the Milky Way using space-based X-ray telescopes. Each burst results from a thermonuclear explosion on the surface of an accreting neutron star in a close binary system. Along with various astrophysical parameters, X-ray burst models are sensitive to nuclear uncertainties. Among the most significant nuclear uncertainties identified are the thermonuclear rates of the $^{15}$O($\alpha$,$\gamma$)$^{19}$Ne, $^{59}$Cu(p,$\gamma$)$^{60}$Zn, and $^{59}$Cu(p,$\alpha$)$^{56}$Ni reactions. To address these uncertainties, an experimental campaign was recently completed at FRIB using the beta decays of $^{20}$Mg and $^{60}$Ga and the Gaseous Detector with Germanium Tagging II (GADGET II) system. The goals are to measure the alpha-particle branching ratio of the key $^{19}$Ne resonance, and to discover and characterize resonances in $^{60}$Zn by their energies, spins/parities, and branching ratios. Preliminary analysis of these data sets will be presented, along with plans to follow up by measuring $^{60}$Zn resonance lifetimes using $^{60}$Ga decay and the new Lifetimes and Branching Ratios Apparatus (LIBRA) system, also at FRIB.