Study of theAl27(He3, p)Si29andAl27(He3, pγ)Si29Reactions

The levels of ${\mathrm{Si}}^{29}$ have been studied by measuring angular distributions of the ${\mathrm{Al}}^{27}({\mathrm{He}}^3, p){\mathrm{Si}}^{29}$ reaction. A few states, in particular the level at 8.310 MeV (the analog of the ${\mathrm{Al}}^{29}$ ground state), were strongly excited with an orbital angular momentum transfer $L=0\mathrm{}$ leading to states with $J={\frac{3}{2}}^{+}, {\frac{5}{2}}^{+}$, and possibly ${\frac{7}{2}}^{+}$. The $\gamma$ decay of some of these levels has been studied by $p-\gamma$ coincidences. They all showed a very similar $\gamma$ decay, namely, a preference to decay to those few positive-parity states that are also strongly populated in the (${\mathrm{He}}^3$, $p$) reaction. From the radiative decay of the 8.310-MeV level and other evidence, we conclude that the ${\frac{5}{2}}^{+}$ state at 4.906 MeV contains the major portion of the antianalog strength. The coincidence data also contained events from ${\mathrm{Al}}^{27}({\mathrm{He}}^3, d\gamma ){\mathrm{Si}}^{28}$. Analysis of these results showed that it was consistent with previous measurements.