$^{18}$F(\textit{a},p)$^{21}$Ne reaction study for astrophysical implications

As an alternative neutron source for the weak r-process, one of models suggested the r-process nucleosynthesis in the supernova shock passing through the He-rich shell of the pre-supernova star. In this helium rich environment, a possible neutron source for the second r-process would be the reaction sequence $^{14}$N($\alpha $,$\gamma )^{18}$F($\alpha $,p)$^{21}$Ne($\alpha $,n)$^{24}$Mg with rapid depletion of $^{14}$N. The ($\alpha $,p) reaction on $^{18}$F will be faster than $\beta ^{+}$ decay at the high densities and temperature in the shock. The $^{18}$F($\alpha $,p)$^{21}$Ne reaction and the inverse reaction $^{21}$Ne(p,$\alpha )^{18}$F have been measured in the energy range of the Gamow window. Experimental results will be presented and compared with Hauser-Feshbach calculations and the interests in nuclear physics. The astrophysical implications of the new reaction rates will be discussed.