Interaction of Fast Neutrons with Nitrogen

Using neutrons from the ${\mathrm{Li}}^7\mathrm{}(p,n)\mathrm{}{\mathrm{Be}}^7$ reaction, the cross sections for the reactions ${\mathrm{N}}^{14}\mathrm{}(n,p)\mathrm{}{\mathrm{C}}^{14}$ and ${\mathrm{N}}^{14}(n,\alpha ){\mathrm{B}}^{11}$ were measured for neutron energies from 150 to 2100 kev. Resonances for the ($n,p$) reaction were found at 499, 640, 993, and 1415 kev; for the ($n,\alpha$) reaction at 1415 and 1800 kev. Information was obtained about the excited state of ${\mathrm{Be}}^7$. It was found to lie 431±5 kev above the ground state, and probabilities for its formation in the $\mathrm{Li}\mathrm{}(p,n)\mathrm{}$ reaction were determined.