The energy levels of ${\mathrm{Be}}^7$ and ${\mathrm{B}}^9$ have been studied by observation of the alpha-particle spectra resulting from the reactions ${\mathrm{B}}^{10}(p, \alpha ){\mathrm{Be}}^7$ and ${\mathrm{C}}^{12}(p, \alpha ){\mathrm{B}}^9$. Alpha groups were observed corresponding to the ground state of ${\mathrm{B}}^9$ and an excited state at 2.39±0.08 Mev. Groups were observed corresponding to ${\mathrm{Be}}^7$ being left in the ground state and excited states of the following energies: 0.49±0.10 Mev, 4.72±0.08 Mev, 6.27±0.10 Mev, 7.21±0.10 Mev, 14.6±0.3 Mev.

• Received 10 February 1955

DOI:https://doi.org/10.1103/PhysRev.98.1289