The first excited state of 30Ne studied by proton inelastic scattering in reversed kinematics

The energy of the first excited state of the very neutron-rich nucleus 30Ne was determined by proton inelastic scattering. A liquid hydrogen target was bombarded by a beam of radioactive 30Ne at 48 MeV/nucleon, and energies of the de-excitation γ rays emitted from the excited 30Ne were measured. The observed transition is likely to be the one from the first 2+ state to the ground state of 30Ne. The excitation energy, 791(26) keV, is lower than that of 32Mg, indicating enhancement of deformation as the neutron excess increases in the N=20 isotones. The results indicate that 30Ne belongs to the ‘island of inversion’.