Excitation of deep lying hole states inC11,O15,Si27, andNi57with the (He3,α) reaction at 216 MeV

Abstract

The $\ensuremath{\alpha}$ spectra were investigated in the discrete and continuum regions. In addition to the well known low lying levels, peaks and broad structures are observed for each nucleus at higher excitation energies. The bumps location and spreading, and their forward peaked distributions, suggest that they arise from neutron pickup in the deeper shells, i.e., $1s$ for $^{12}\mathrm{C}$ and $^{16}\mathrm{O}$, $1{p}_{\frac{3}{2}}$ for $^{28}\mathrm{Si}$ and $1d+(1p)$ for $^{58}\mathrm{Ni}$.NUCLEAR REACTIONS $^{12}\mathrm{C}$, $^{16}\mathrm{O}$, $^{28}\mathrm{Si}$, $^{58}\mathrm{Ni}(^{3}\mathrm{He}, \ensuremath{\alpha})$, $E=216$ MeV; measured $\ensuremath{\sigma}(E\ensuremath{\alpha}; \ensuremath{\theta})$; high excitation energy observed levels and broad structure in $^{11}\mathrm{C}$, $^{15}\mathrm{O}$, $^{27}\mathrm{Si}$, and $^{57}\mathrm{Ni}$.