P31(He3,d)S32reaction at 25 MeV

Abstract

The $^{31}\mathrm{P}(^{3}\mathrm{He},d)^{32}\mathrm{S}$ reaction was investigated at 25 MeV incident energy. One-hundred and eleven levels up to an excitation energy of 12.5 MeV were observed using a split-pole magnetic spectrograph. The experimental angular distributions were analyzed with the distorted-wave Born approximation. The optical model parameters used in the distorted-wave Born-approximation calculations were obtained from a fit to elastic $^{3}\mathrm{He}$ scattering data taken on $^{31}\mathrm{P}$ at 25 MeV. Gamow functions were used as form factors for the transferred proton in the case of unbound states. Values of the transferred orbital angular momenta $l$ and spectroscopic strengths were obtained for sixty levels, with many odd-parity levels being observed above 9 MeV excitation. Spin and parity assignments were made upon the basis of the $l$ values obtained from the shapes of the angular distributions and upon comparison with the results of other reactions. Isospin assignments were made by comparison with $^{32}\mathrm{P}$ levels. Except for the ${l}_{p}=1$, $T=0$ transfers, most of the observed spectroscopic strength is concentrated into a few levels. The existence of a $T$-mixed doublet of levels, ${J}^{\ensuremath{\pi}}={1}^{\ensuremath{-}}$, is suggested in the 11 MeV region of excitation. The excitation energies and spectroscopic strengths are compared with results of a recent shell-model calculation.NUCLEAR REACTIONS $^{31}\mathrm{P}(^{3}\mathrm{He},d)$, $^{31}\mathrm{P}$($^{3}\mathrm{He}$, $^{3}\mathrm{He}$), $E=25$ MeV; measured $\ensuremath{\sigma}({E}_{d},\ensuremath{\theta})$, $^{32}\mathrm{S}$ deduced levels, $l$, $J$, $\ensuremath{\pi}$, $T$, spectroscopic strengths; measured $\ensuremath{\sigma}(\ensuremath{\theta})$, deduced optical model parameters. DWBA analysis using Gamow functions as form factors.