The reaction ${}_{}{}^3{}_{}{}^{}\mathrm{He}+{}_{}{}^3{}_{}{}^{}\mathrm{He}\to {}_{}{}^6{}_{}{}^{}\mathrm{Be}_{}^{*}{}_{}{}^{}+\gamma$ was observed at 90° for bombarding energies between 0.86 and 11.8 MeV. The total cross section for transitions to the first excited state of ${}_{}{}^6{}_{}{}^{}\mathrm{Be}$ varies smoothly from 0.4 to 9.3 μb (assuming isotropy). No $\gamma$-ray transitions to the ground state of ${}_{}{}^6{}_{}{}^{}\mathrm{Be}$ were observed with an upper limit of approximately ${10}^{-2\mathrm{}}$ μb at 1.4 MeV. Because of these low cross sections, this reaction is of negligible astrophysical importance compared to the ${}_{}{}^3{}_{}{}^{}\mathrm{He}({}_{}{}^3{}_{}{}^{}\mathrm{He}, 2p){}_{}{}^4{}_{}{}^{}\mathrm{He}$ reaction.

• Received 13 April 1967

DOI:https://doi.org/10.1103/PhysRev.160.752