The differential cross section for the elastic scattering of protons by ${\mathrm{C}}^{13}$ has been determined in the energy range from 0.45 to 1.60 Mev at angles of 50, 90, 120, 140, and 160 degrees in the center-of-mass system. Marked anomalies were found in the scattering at 0.55, 1.16, 1.47, and 1.55 Mev corresponding to excited states in ${\mathrm{N}}^{14}$ at 8.06, 8.62, 8.90, and 8.98 Mev. The spins and parities of these states have been determined from a preliminary analysis of the data which also indicates an effect due to the broad resonance at 1.25 Mev in ${\mathrm{C}}^{13}(p, \gamma ){\mathrm{N}}^{14}$ corresponding to an excited state in ${\mathrm{N}}^{14}$ at 8.70 Mev. The assignment for the 8.06-Mev level is $J=1^{-}$, for the 8.62-Mev level $J=0^{+}$ and for the broad 8.70 Mev level $J=0^{-}$. The probable assignment for the 8.90-Mev level is $J=3^{-}$ and for the 8.98-Mev level $J=1^{+}$.

The elastic scattering of protons by ${\mathrm{C}}^{12}$ was also measured from 300 kev to 550 kev at angles of every ten degrees in the center-of-mass system from 30 to 160 degrees.

• Received 2 November 1953

DOI:https://doi.org/10.1103/PhysRev.93.762