16O(α, γ) 20Ne capture γ-ray measurements on the excited Kπ = 0 + bands in 20Ne near 7 MeV

Abstract

Radiative widths have been measured for the E α = 3074 keV ( J π = 0 +), 3363 keV ( J π = 2 +), 3872 keV ( J π = 2 +) and 5368 keV ( J π = 4 + z) resonances in the 16O(α,γ) 20Ne reaction, corresponding to level energies at 7191±3, 7420±1, 7826±3 and 9029±3 keV respectively. The radiative widths for decay to the 2 +, first excited state and the 0 +, ground state of 20Ne are: 7191 → 1633 (4.35±0.75 meV), 7420 → 1633 (29±4 meV), 7420 → 0 (≦3.0±0.6 meV), 7826 → 1633 (11.7±1.6 meV), 7826 → 0 (57±7 meV) and 9029 → 1633 (340±42 meV). The following upper limits on the decay widths to the 4 +, 4246 keV level were also obtained: 7420 → 4246 (< 2.2 meV), 7826 → 4246 (< 2 meV) and 9029 → 4246 (< 6.8 meV). The experimentally known interband electromagnetic matrix elements are compared with nuclear model predictions. The excitation energy region from 10.2 to 10.8 MeV in 20Ne has been searched for a possible E x → E(4 +, 4246 keV) transition and an upper limit of ωγ < 0.6 eV can be placed on such a transition.