Interference between Coulomb and nuclear excitation in the inelastic scattering ofNe22fromSr88

Abstract

We have measured the excitation function at ${\ensuremath{\theta}}_{\mathrm{lab}}=175\ifmmode^\circ\else\textdegree\fi{}$ for the excitation of the first ${2}^{+}$ state in $^{88}\mathrm{Sr}^{*}$ by inelastic scattering of $^{22}\mathrm{Ne}$. At the same time we obtained similar data for the excitation of the first ${2}^{+}$ state of the beam particle itself. The measurements span the energy range 49-65 MeV containing the region of the Coulomb-nuclear interference. In terms of Rutherford trajectories, the $^{22}\mathrm{Ne}^{*}$ interference minimum is located at a separation \ensuremath{\sim} 0.2 fm greater than for $^{88}\mathrm{Sr}^{*}$. An optical potential was obtained by a fit to elastic scattering data consisting of an excitation function at ${\ensuremath{\theta}}_{\mathrm{lab}}=175\ifmmode^\circ\else\textdegree\fi{}$ and an angular distribution at 65.4 MeV lab. A collective model distorted-wave Born-approximation calculation with this potential can account for the $^{88}\mathrm{Sr}^{*}$ data but fails to describe the shape of the $^{22}\mathrm{Ne}^{*}$ excitation function.NUCLEAR REACTIONS $^{88}\mathrm{Sr}$($^{22}\mathrm{Ne}$, $^{22}\mathrm{Ne}$), $E=49\ensuremath{-}65$ MeV; measured $d\ensuremath{\sigma}(E)$ at ${\ensuremath{\theta}}_{1}=175\ifmmode^\circ\else\textdegree\fi{}$ for g.s., first ${2}^{+}$ state in $^{88}\mathrm{Sr}$ and $^{22}\mathrm{Ne}$, $d\ensuremath{\sigma}(\ensuremath{\theta})$ at 65.4 MeV for g.s.; deduced optical model potential, deformation parameters. Enriched target.