Spectroscopy of the proton drip line nucleus 19Na by 1H(18Ne,p)18Ne elastic scattering Original Research Article

We have studied the resonant elastic scattering reaction 18Ne+p in reverse kinematics, by using the intense (4 × 106 pps) 18Ne radioactive beam at the Centre de Recherches du Cyclotron RIB facility at Louvain-la-Neuve. The recoil protons were detected at 20 different angles in the LEDA segmented silicon detector. The resulting elastic scattering cross sections have been analysed using the R-matrix method. We have observed for the first time the second excited state (Jπ = 1/2+, ℓ = 0) of the proton-rich nucleus 19Na at the center-of-mass energy Ec.m. = 1.066 ± 0.003 MeV with a proton width Γp = 101 ± 3 keV. The Coulomb shift between the 1/2+ mirror levels in 190 and 19Na is 0.73 MeV, among the largest values currently observed in light exotic nuclei.