Comparison of Nitrogen- and Proton-Induced Nuclear Reactions

Excitation functions for ($p, 2p$), (p, α), and (p, 2α) reactions on Mg²⁵ were measured with the internal 22-Mev proton beam of the 86-inch cyclotron. The results are compared with the excitation functions obtained for the reactions produced by 29-Mev nitrogen ions on carbon in the 63-inch cyclotron. Both sets of reactions may proceed via the same compound nucleus, Al²⁶. After corrections for the barrier penetrations of the incident particles, the (N, $2p$) and ($p, 2p$) results are quite comparable. The corrected (N, α) and (N, 2α) cross sections are larger than those for the corresponding proton-induced reactions by factors of about two and four respectively, indicating that processes other than conventional compound nucleus formation are involved in these nitrogen-induced reactions. The shape of the excitation functions for the nitrogen-induced reactions indicates that the protons and alpha particles are emitted from nearly spherical nuclei with charge equal to that of the compound nucleus; direct interactions such as stripping are thus excluded.