Interaction cross sections for Ne isotopes towards the island of inversion and halo structures of 29Ne and 31Ne

Interaction cross sections (sigma(1)) for Me isotopes from the stability line to the vicinity of the neutron drip line have been measured at around 240 MeV/nucleon using BigRIPS at RIBF, RIKEN, The sigma(1) for Ne27-32 in every case exceed the systematic mass-number dependence of sigma(1) for stable nuclei, which can be explained by considering the nuclear deformation. In particular the sigma(1) for Ne-29 and Ne-31 are significantly greater than those of their neighboring nuclides. These enhancements of sigma(1) for Ne-29 and Ne-31 cannot be explained by a single-particle model calculation under the assumption that the valence neutron of Ne-29 (Ne-31) occupies the 0d(3/2) (0f(7/2)) orbital, as expected from the standard spherical shell ordering. The present data suggest an s dominant halo structure of Ne-29 and s- or p-orbital halo in Ne-31. (C) 2011 Elsevier B.V. All rights reserved.