Radiative decays of unbound levels in 20Ne

Nine levels in the range 8.7 to 12.5 MeV in 20Ne have been investigated with the 16O(α, γ)20Ne and 16O(α, α')16O*(6.13 MeV) reactions using a differentially pumped windowless gas target. Three of the levels have not been observed previously in these reactions, and new information has been obtained for most of the others. In particular, the 11.27 MeV 1- level is shown to have T = 1, a result of relevance to a proposed parity violation experiment, and the analogue of the 1.97 MeV (3- T = 1) level in 20F is shown to lie at 12.25 MeV in 20Ne rather than at 12.39 MeV as proposed previously. In addition, the 12.25 MeV level has a width Γ < 1 keV, in contrast to the value Γ ∼ 5 keV reported in other work. The electromagnetic transition rates for positive parity T = 1 states in 20Ne are compared with shell-model calculations. © 1980.