Beta decay of 16C and 17N

The delayed neutron emitters 16C and 17N have been studied in the reaction 14C(18O,16O)16C with 56-MeV 18O ions, and also in the reaction 11B(7Li,2p)16C with 40-MeV 7Li ions. The thermalized neutrons following both reactions yield together a 16C half-life of 0.747+-0.008 sec with the well-known 4.17-sec 17N activity as an accompaniment formed in the 14C(18O,17N)15N and 11B(7Li,p)17N reactions. The neutron spectra in a bare 3He detector contain 16C lines of 0.79+-0.03 MeV and 1.72+-0.05 MeV in addition to 17N peaks. The 16C neutron groups are assigned to the β decay to the known 3.36- and 4.32-MeV 1+ states of 16N. A search for γ rays associated with 16C forbidden β decay to the 0-, 3-, and 1- levels of 16N gave upper limits for the respective branching ratios. The logft values for β decay to the 3.36- and 4.32-MeV states, 3.551+-0.012 and 3.83+-0.05, respectively, disagree seriously with preliminary theoretical values of 5.17 and 4.66, respectively, due to Millener. Separate studies were made of 17N decay, formed in the 15N(t,p)17N reaction at E/subt/=3.0 MeV. By using an empirical neutron efficiency function, β-ray branches of 17N to the 17O neutron-emitting states at 4.55, 5.38, and 5.94 MeV were found to be in disagreement with two previously reported measurements. γ-ray measurements on 17N with a Ge(Li) detector yielded the : ratio of β-ray branching intensities. The mirror β decays of the A=17 system are discussed