High-Precision Measurements of Excited States in 24Mg Using GRETINA and FMA

The origin of the Na–O anticorrelation in globular cluster stars remains an open question in nuclear astrophysics, requiring reliable nuclear input. The reaction rate for 23Na(p,γ)24Mg plays an important role in sodium destruction and is dominated by a narrow resonance at Ex ≈ 11.823 MeV near 80 MK. A recent (3He,d) experiment at TUNL revealed inconsistencies among previous energy measurements of this state, leading to significant uncertainty in the reaction rate. To address this, a 16O(10B,np)24Mg fusion-evaporation experiment was performed using GRETINA and the FMA at Argonne National Laboratory, aiming for a precise determination of this near-threshold state. Several transitions associated with known low-spin states from the (3He,d) study were populated and will help refine energy calibrations for resonance energy determinations. In addition, several previously unreported high-energy γ transitions were identified, and their energies were determined using precise Doppler corrections, contributing to improved knowledge of the 24Mg level structure in the high-excitation region.