Cross sections have been measured for the production of ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ and ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ from the reactions ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}(p,2\mathrm{}\alpha ){}_{}{}^7{}_{}{}^{}\mathrm{Be}$ and ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}(p,\alpha ){}_{}{}^{11}{}_{}{}^{}\mathrm{C}$ from near threshold to 24 and 22 MeV, respectively, and for the production of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ and ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$ in $\alpha$-particle bombardment of ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ up to 42 MeV. The proton reactions were studied with activation techniques and the $\alpha$-particle reactions investigated using time-of-flight particle identification. These cross sections are of interest because of their relevance to the production of the light elements in nature by relatively low-energy particles. Analyses of comparative production cross sections from CNO targets indicate that it is possible to match the solar system abundances of LiBeB with reactions dominated by protons of energies below about 25 MeV, provided one accepts the higher of recent estimates of the B abundance.

[NUCLEAR REACTIONS ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}(p,2\mathrm{}\alpha )$, $E=14-24\mathrm{}$ MeV; ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}(p,\alpha )$, $E=5-22\mathrm{}$ MeV; ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}(\alpha ,{}_{}{}^{10}{}_{}{}^{}\mathrm{B})$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}(\alpha ,{}_{}{}^6{}_{}{}^{}\mathrm{Li})$, $E=21-42\mathrm{}$ MeV; measured $\sigma \mathrm{}\left(E\right)\mathrm{}$. Astrophysical production of Li and B.]

• Received 28 January 1974

DOI:https://doi.org/10.1103/PhysRevC.9.2134