Proton scattering from 9Be between 6 and 30 MeV and the structure of 9Be

Abstract

Differential cross-section excitation functions at lab scattering angles 86.9°, 120.0°, 140.0° and 160.0° were measured for 9Be(p, p o) 9Be, 9Be(p, p 2) 9Be and 9Be(p, d 0) 8Be at proton lab energies from 6 to 15 MeV in 100 keV steps. A broad anomaly was observed in the 9Be(p, p 0) 9Be excitation functions. Differential cross-section angular distributions were measured for 9Be(p, p 0) 9Be and 9Be(p, p 2) 9Be at lab energies of 13.0, 14.0, 15.0, 21.35 and 30.3 MeV and for 9Be(p, d 0) 8Be at 13.0, 14.0, 15.0 and 21.35 MeV. Angular distributions of polarization analysing powers for 9Be( p ,p 0) 9Be, 9Be(p, p 2) 9Be and 9Be( p , d 0) 8Be were measured at 8.0, 11.0, 12.0, 13.0 and 15.0 MeV. A spherical optical-model (SOM) analysis of the elastic scattering angular distribution data from 13.0 to 30.3 MeV showed that an energy dependence of only V R and W s (volume real and surface imaginary depths) is sufficient to reproduce the measurements. Coupled-channels (CC) analyses were made with a quadrupole-deformed optical-model potential and strong coupling of 3 2 − , 5 2 − and 7 2 − levels of a K = 3 2 ground-state rotational band of 9Be. The 9Be(p, p 0) 9Be and 9Be(p, p 2) 9Be data from 13.0 to 30.3 MeV were analyzed simultaneously at each energy, varying only V R and W s with energy, for a potential deformation of β = 1.1. Both SOM and CC analyses indicated the same energy dependence in V R, while W s averaged 3.5 MeV lower in CC than in SOM, with both energy dependences consistent with previous analyses of nucleon scattering from 1p shell nuclei.