The disintegration of ${\mathrm{Be}}^9$ by 21.7-Mev alpha-particles has been studied with observations of the emitted particles made at various angles. $Q$-values of -6.92, -7.87, -8.57, and -10.74 Mev were found for the ${\mathrm{Be}}^9(\alpha ,p){\mathrm{B}}^{12}$ reaction giving levels in ${\mathrm{B}}^{12}$ at 0.95, 1.65, and 3.82 Mev. Two groups of deuterons from ${\mathrm{Be}}^9(\alpha ,d){\mathrm{B}}^{11}$ were found giving a level in ${\mathrm{B}}^{11}$ at 2.18 Mev. A third group, if assigned to this reaction would give a level in ${\mathrm{B}}^{11}$ at 0.65 Mev. The inelastic scattering ${\mathrm{Be}}^9(\alpha ,{\alpha }^{\prime }){\mathrm{Be}}^{9*}$ gives a level in ${\mathrm{Be}}^9$ at 2.63 Mev.

• Received 27 August 1951

DOI:https://doi.org/10.1103/PhysRev.84.963