Proton Decay of 21Na for 20Ne Energy Levels

The 24Mg(p,α)21 Na transfer reaction has been previously studied for a spectroscopic study of 21Na [Cha et al., Phys. Rev. C 96, 025810 (2017)]. In this follow-up analysis, the proton decays of the excited states of the radionuclide 21Na, which were measured simultaneously, are reported. By investigating the coincidence between the reaction α-particles and decay protons, we were able to identify three groups of events that are associated with the energy levels in 20Ne. The 20Ne excitation energy plot was obtained as a result. The four lowest known energy levels in 20Ne (the ground state and excited states at Ex = 1.633, 4.247 and 4.966 MeV) were clearly observed.