21Ne energy levels approaching the $α$-particle threshold

Background: Nuclei around 20Ne exhibit an interplay of different excitations caused by different aspects of nuclear structure, including single-particle and multiparticle configurations and collective rotations. One-nucleon transfer reactions selectively probe single-particle structures in these nuclei. These nuclei are also important to astrophysics, with a number of important reactions proceeding through this mass region. Purpose: Energy levels approaching the α-particle threshold in 21Ne are of importance to nuclear structure. The 20Ne (d, p) 21Ne reaction was measured and the corresponding spectroscopic nuclear information was extracted. Method: States in 21Ne were populated using the 20Ne (d, p) 21Ne reaction in forward kinematics. Protons were identified in the Triangle Universities Nuclear Laboratory (TUNL) Enge split-pole spectrograph and angular distributions were extracted. Spin-party assignments were made and neutron partial widths were determined based on distorted-wave Born approximation (DWBA) analysis. Results: Several new energy levels were observed at energies of 7176, 7235, 7250, and 7337 keV, and spin-parities are reported which generally agree with previous results where literature was available. Spin and parity assignments are reported for several energy levels along with estimated neutron widths for those states above the neutron threshold (Sn = 6761 keV). Conclusions: Results from this study are placed in context with a review of the available literature on all known states in this energy region of 21Ne.