The energies of the delayed neutrons which follow the decay of ${\mathrm{N}}^{17}$ have been measured by means of a triple proportional-counter recoil spectrometer. The ${\mathrm{N}}^{17}$ was obtained from the ${\mathrm{C}}^{14}(\alpha , p){\mathrm{N}}^{17}$ reaction at a mean $\alpha$-particle energy of 25-Mev. Two neutron groups were observed, with energies of 1.22±0.06 Mev and 0.426±0.018 Mev. These correspond to neutron groups were observed, with energies of 1.22±0.06 Mev and 0.426±0.018 Mev. These correspond to neutron emission from the ${\frac{3}{2}}^{-}$states of ${\mathrm{O}}^{17}$ at 5.38 and 4.55 Mev, respectively. This result is consistent with the expected $J^{\pi }$ of ${\mathrm{½}}^{-}$ for the ground state of ${\mathrm{N}}^{17}$ and with the small stripping widths for these levels in ${\mathrm{O}}^{16}(d, p){\mathrm{O}}^{17}$. The ratio of the intensity of the high-energy group to the low-energy one is 1.6, which corresponds to a ratio of 4 for the squares of the $\beta$-decay matrix elements.

• Received 19 December 1960

DOI:https://doi.org/10.1103/PhysRev.122.899