N14(p,α)C11cross sections from 3.8 to 6.4 MeV

Total cross sections for the $^{14}\mathrm{N}(p,\ensuremath{\alpha})^{11}\mathrm{C}$ reaction have been measured by using sealed gas targets and detecting annihilation radiation from the positron decay of $^{11}\mathrm{C}$. These measurements agree with the recent work of Jacobs et al. above 5.0 MeV and extend the measured cross sections to 3.8 MeV, where the cross section is a factor of 1000 smaller than the higher-energy cross sections. The results determine the low-energy normalization of the inverse $^{11}\mathrm{C}(\ensuremath{\alpha},p)^{14}\mathrm{N}$ reaction, reducing the $^{14}\mathrm{N}$ production in big bang model calculations relative to results obtained by using estimated cross sections.NUCLEAR REACTIONS $^{14}\mathrm{N}(p,\ensuremath{\alpha})$, $E=3.8\ensuremath{-}6.4$ MeV, measured $\ensuremath{\sigma}(E)$. Inferred $\ensuremath{\sigma}(E)$ and astrophysical cross section factor for inverse reaction. Sealed gas target.