A ${\mathrm{Li}}^7$ oxide layer deposited on a carbon foil has been bombarded by 13-MeV tritons from the Aldermaston tandem. The spectra of $\alpha$ particles emitted at 24 angles relative to the incident beam (5° to 175°) have been determined with the Aldermaston multigap spectrograph, using nuclear plates as detectors. The first excited state of ${\mathrm{He}}^6$ is found to have an excitation energy of 1.797±0.025 MeV and a width of 113±20 keV No other excited states of ${\mathrm{He}}^6$ below an excitation energy of 12 MeV have been observed, for $\theta =5\mathrm{}° \mathrm{to} 35°$. Angular distributions of $\alpha$ particles have been determined to the following states: $E_x=0\mathrm{} \mathrm{and} 1.80$ MeV in ${\mathrm{He}}^6$; $E_x=0, 5.28+5.31, \mathrm{and} 6.33$ MeV in ${\mathrm{N}}^{15}$; $E_x=0, 2.14, 4.46, \mathrm{and} 5.03$ MeV in ${\mathrm{B}}^{11}$. The angular distributions show strong direct-interaction features.

• Received 22 March 1965

DOI:https://doi.org/10.1103/PhysRev.139.B592