Beta-delayed particle decay of 17Ne

Abstract

The β-delayed particle decay of 17Ne has been studied via proton– γ coincidences, time-of-flight measurements and the “ratio-cut technique”, allowing cleanly-separated proton and α-particle spectra to be obtained. A complete set of proton and α branching ratios for the decay of 14 excited states in 17F to the ground and excited states of 16O and 13N has been determined and branching ratios for the β decay of 17Ne to these states have been deduced. From the branching ratios, f A t values and reduced Gamow–Teller matrix elements were calculated; no indication of isospin mixing in the isobaric analog state in 17F was observed. From the measurement of proton– γ angular correlations, combined with the selection rules for an allowed β decay, we obtain J π= 1 2 − for states at 8.436 and 9.450 MeV and 3 2 − for the state at 10.030 MeV in 17F. Probabilities for the β-delayed p α decay to 12C through the tails of the subthreshold 7.117 and 6.917 MeV states in 16O have been calculated and the feasibility of using such decays to provide information about the rates for the E1 and E2 components of the 12C( α, γ) 16O reaction is discussed.