Quadrupole deformation of 12Be studied by proton inelastic scattering

Inelastic proton scattering exciting the 2(1)(+) states in the neutron-rich beryllium isotopes Be-10,Be-12 has been studied in inverse kinematics. From a coupled-channel analysis, the deformation lengths for the 2(1)(+) states in Be-10 and Be-12 were determined to be 1.80 +/- 0.25 fm and 2.00 +/- 0.23 fm respectively, indicating that a tendency towards strong quadrupole deformation is preserved for these nuclei and that the singly-closed shell structure does not prevail in Be-12. A quantitative analysis based on shell model calculations supports this picture. (C) 2000 Elsevier Science B.V. All rights reserved.