We have studied the reaction ${\mathrm{B}}^{11}({\mathrm{He}}^3, \alpha ){\mathrm{B}}^{10}$ at 60 and 90° at an incident energy $E_{{\mathrm{He}}^3}=4.9596\mathrm{}\pm 0.0030$ MeV and at 75° at $E_{{\mathrm{He}}^3}=4.7689\mathrm{}\pm 0.0030$ MeV. The energies of the ${\mathrm{B}}^{10}$ states found by other authors have been confirmed except for those found at 6.04 and 6.16 MeV for which we obtain the values 6.028±0.005 MeV and 6.131±0.005 MeV, respectively. The differential cross sections of this reaction have been measured at the same three angles and are given up to the 7.56-MeV state. We have found the ${\mathrm{B}}^{11}({\mathrm{He}}^3, t_0){\mathrm{C}}^{11}$ reaction with a differential cross section of 0.32±0.08 mb/sr at ${\theta }_{t_0}=60\mathrm{}°$, of 0.26±0.07 mb/sr at 75° and of 0.21±0.05 mb/sr at 90° at the ${\mathrm{He}}^3$ energies mentioned above.

• Received 3 November 1964

DOI:https://doi.org/10.1103/PhysRev.137.B1466