Radiative decays of unbound high spin states in 24Mg

Abstract

Abstract The 20Ne(α, γ)24Mg reaction has been used to measure radiative decay rates for known high spin levels at 12.86(6+), 13.44(6+) and 14.15(8+) MeV in 24Mg, and for previously unidentified levels at 12.00, 13.04 and 14.08 MeV. Gamma-ray angular distributions indicate that the 12.00 and 14.08 MeV levels are probably 6+ levels, while the 13.04 MeV level is the lowest 0+ T = 1 state. A new level at 11.005 MeV, populated in the radiative decay of the 14.08 MeV level, is most likely the lowest 5+ T = 1 state in 24Mg. Alpha-particle widths have also been measured for several of these levels and for the known 6+ level at 13.85 MeV using the 20Ne(α, α′γ)20Ne reaction and previously determined branching ratios. The results for both radiative and particle decay widths are compared with recent shell-model calculations performed within a full (sd)8 basis.