Studying Electron-Capture on $^{64}$Zn in Supernovae with the (t,$^{3}$He) Charge-Exchange Reaction

A secondary, 115 MeV/u triton beam has been developed at NSCL for use in (t,$^{3}$He) charge-exchange(CE) reaction studies. This (n,p)-type CE reaction is useful for extracting the full Gamow-Teller (GT) response of the nucleus, overcoming Q-value restrictions present in conventional beta-decay studies. The strength (B(GT)) in $^{64}$Cu has been determined from the absolute cross section measurement of $^{64}$Zn(t,$^{3}$He) near zero-degrees, exploiting an empirical proportionality between cross section and B(GT). The detailed features of the B(GT) distribution in a nucleus has an important impact on electron-capture (EC) rates in Type Ia and Core-Collapse supernovae. The measured B(GT) in $^{64}$Cu is directly compared with the results of modern shell model interactions which are used to calculate the GT contribution to EC on nuclei in supernova simulations.