Elastic and Inelastic Scattering of Protons byN14

Abstract

Differential cross sections for the elastic scattering of protons by ${\mathrm{N}}^{14}$ have been measured for proton energies between 1.0 and 4.1 Mev at center-of-mass scattering angles of 90.0\ifmmode^\circ\else\textdegree\fi{} and 168.1\ifmmode^\circ\else\textdegree\fi{}. Above 3.5 Mev the study was extended to four additional angles, 140.8\ifmmode^\circ\else\textdegree\fi{}, 125.3\ifmmode^\circ\else\textdegree\fi{}, 54.7\ifmmode^\circ\else\textdegree\fi{}, and 39.2\ifmmode^\circ\else\textdegree\fi{}, to provide information on a broad resonance near 3.9 Mev and a narrower resonance at 3.980 Mev. These two resonances also exhibit a measurable width for inelastic scattering to the first excited state of ${\mathrm{N}}^{14}$ at 2.31 Mev. All measurements were made with a differentially-pumped scattering chamber containing natural nitrogen gas. The probable error in the cross section is estimated at 3%; the energies of the incident protons were determined to \ifmmode\pm\else\textpm\fi{}3 kev. The data were analyzed to provide information on the resonance energies ${E}_{r}$ and total widths $\ensuremath{\Gamma}$. Evidence was found for a previously unreported level with ${E}_{r}=2.535$ Mev, $\ensuremath{\Gamma}\ensuremath{\cong}1.8$ kev. From an investigation of the elastic and inelastic scattering data in the region of the level at 3.9 Mev it is concluded that the resonance is due to $d$-wave formation of a state of ${\mathrm{O}}^{15}$ having spin and parity ${\frac{5}{2}}^{+}$, with ${E}_{r}=3.878\ifmmode\pm\else\textpm\fi{}0.008$ Mev, $\ensuremath{\Gamma}=85\ifmmode\pm\else\textpm\fi{}8$ kev, ${\ensuremath{\Gamma}}_{i}=7$ kev.