Study of the (d,p) Reaction onGe70

Abstract

The reaction ${\mathrm{Ge}}^{70}\mathrm{}(d,p)\mathrm{}{\mathrm{Ge}}^{71}$ has been studied at a bombarding energy of 7.5 MeV using the MIT Van de Graaff accelerator and multigap spectrograph with photographic-plate detectors. With an energy resolution of 25 keV, 86 levels were identified up to an excitation energy of 4.5 MeV. The angular distribution of the proton groups showing stripping characteristics were analyzed by use of the distorted-wave Born approximation, and values of orbital-angular-momentum transfer $l_n$ were assigned to approximately 40 levels. For $l_n=1\mathrm{}$ levels, $j$ values were determined by the Lee-Schiffer effect. The sum of the spectroscopic factors (occupation number) for the 28-50-neutron shell are $p_{\frac{1}{2}}-0.5$, $p_{\frac{3}{2}}-0.03$, $f_{\frac{5}{2}}-0.3$, and $g_{\frac{9}{2}}-0.7$. Single-quasiparticle energies for the same shell are approximately $E_{\frac{9}{2}}=0.2\mathrm{}$, $E_{\frac{1}{2}}=0.30\mathrm{}$, $E_{\frac{5}{2}}=1.3\mathrm{}$, and $E_{\frac{3}{2}}=2.0\mathrm{}$ MeV. The occupation numbers are compared with those of neighboring nuclei and pairing theory. The results indicate that in the region of 36-42 neutrons, the neutrons go predominantly into the $g_{\frac{9}{2}}$ state.