Nuclear Reactions Induced by the Nitrogen Bombardment of Sulfur

Thick targets of ZnS, containing natural sulfur, were bombarded with 28-Mev nitrogen ions in the ORNL 63-in. cyclotron. The compound nucleus resulting from bombardment of sulfur-32 with 28-Mev nitrogen ions is ${\mathrm{V}}^{46}$, with an excitation energy of 33.3 Mev. The following nuclear reactions were studied: (1) ${\mathrm{S}}^{32}({\mathrm{N}}^{14}, p){\mathrm{Ti}}^{45}$; (2) ${\mathrm{S}}^{32}({\mathrm{N}}^{14}, 2p){\mathrm{Sc}}^{44}$; (3) ${\mathrm{S}}^{32}({\mathrm{N}}^{14}, 2p){\mathrm{Sc}}^{44m}$; (4) ${\mathrm{S}}^{32}({\mathrm{N}}^{14}, 2pn){\mathrm{Sc}}^{43}$; (5) ${\mathrm{S}}^{32}({\mathrm{N}}^{14}, 2\alpha ){\mathrm{K}}^{38m}$; and (6) ${\mathrm{S}}^{32}$(${\mathrm{N}}^{14}$,${\mathrm{N}}^{13}$)${\mathrm{S}}^{33}$. The yields as a function of incident energy for these reactions were differentiated to obtain excitation functions. The cross sections for (1), (2 and 3), and (5) are compared with calculations based on the statistical theory of compound nucleus decay. Two values of the level density parameter, $a$, were employed, first considering and then ignoring de-excitation of a nucleus by gamma-ray emission. The value $a=\frac{A}{10.5}$ fits the $p$ and $2p$ emission cross sections when gamma emission is considered. The excitation function for reaction (6) agrees well with the systematics of previously studied nitrogen-induced transfer reactions.