(p,α) reaction onNb93andY89

Abstract

The ($p,\ensuremath{\alpha}$) reaction has been studied at 15.2 MeV on $^{93}\mathrm{Nb}$ and $^{89}\mathrm{Y}$ and analyzed using distorted-wave Born-approximation and cluster form factors. The reaction is a direct triton pickup and compound nucleus effects are negligible. In the first case the transferred neutrons are the two extra core neutrons and the reaction behaves like a proton pickup. Positive parity states of $^{90}\mathrm{Zr}$ are populated by the transfer of ${g}_{\frac{9}{2}}$ protons with strengths in good agreement with a simple model; new levels are excited corresponding to ${p}_{\frac{3}{2}}$ and ${f}_{\frac{5}{2}}$ proton holes. In the second case the neutrons are removed from the filled $N=50$ shell; states corresponding to proton and neutron configurations in $^{86}\mathrm{Sr}$ are excited with comparable strengths and it is difficult to get unambiguous spectroscopic information.NUCLEAR REACTIONS $^{93}\mathrm{Nb}(p,\ensuremath{\alpha})$, $^{89}\mathrm{Y}(p,\ensuremath{\alpha})$, ${E}_{p}=15.2$ MeV; measured $\ensuremath{\sigma}({E}_{\ensuremath{\alpha}},\ensuremath{\theta})$, $\ensuremath{\theta}=10\ensuremath{-}160\ifmmode^\circ\else\textdegree\fi{}$, $^{90}\mathrm{Zr}$ levels up to 5.1 MeV, $^{86}\mathrm{Sr}$ levels up to 3 MeV. Reaction mechanism. DWBA analysis.