Alpha spectra from the triton bombardment of natural nitrogen were studied at laboratory angles of 30 and 90° with a double-focusing magnetic spectrometer. Observation of alpha groups from ${\mathrm{N}}^{14}(t, \alpha ){\mathrm{C}}^{13}$ allowed the positions of energy levels in ${\mathrm{C}}^{13}$ to be investigated up to an excitation energy of 12.5 MeV. In addition to previously well-determined levels at lower excitations, levels were observed at 10.736, 10.809, 11.000, 11.078, 11.721, and 12.131 Mev. Standard deviations in these values ranged from 0.020 to 0.030 MeV. Previously reported levels at 5.51, 6.10, and 10.47 MeV were not seen. Certain structural features of the alpha continuum underlying ${\mathrm{C}}^{13}$ groups could be tentatively identified with alpha groups from the two-stage reaction ${\mathrm{N}}^{14}(t, n){\mathrm{O}}^{16*}\left(\alpha \right){\mathrm{C}}^{12}$ proceeding through known levels in ${\mathrm{O}}^{16}$ near 15-MeV excitation. Cross sections are reported for various features of the alpha spectra as well as for corresponding features of the proton spectra.

• Received 4 May 1962

DOI:https://doi.org/10.1103/PhysRev.127.2113