Spectroscopic study of the radionuclide 21Na for the astrophysical 17F(α,p)20Ne reaction rate

Abstract

The 24Mg(p,α)21Na reaction was measured at the Holifield Radioactive Ion Beam Facility of the Oak Ridge National Laboratory to study the spectroscopy of the radionuclide 21Na. A 31-MeV proton beam from the 25 MV tandem accelerator bombarded isotopically enriched 24Mg targets. Recoiling 4He particles were identified by an annular silicon strip detector array. Two energy levels at Ex=6.594 and 7.132 MeV were observed for the first time. By comparing the experimentally obtained angular distributions and distorted wave Born approximation calculations, the spins and parities of 21Na energy levels were constrained. The astrophysically-important 17F(α,p)20Ne reaction rate was also calculated for the first time using resonance parameters for 12 energy levels.