The reaction ${\mathrm{C}}^{14}(p, n){\mathrm{N}}^{14}$ has been studied up to 5-Mev bombarding proton energy with good resolution using targets of high isotopic enrichment. Levels previously unseen in this reaction were found at proton energies of 3.19 Mev ($\Gamma =6\mathrm{}$ kev), 3.38 Mev ($\Gamma =24\mathrm{}$ kev), 3.63 Mev ($\Gamma =13\mathrm{}$ kev), 3.89 Mev ($\Gamma =35\mathrm{}$ kev), 4.19 Mev ($\Gamma =112\mathrm{}$ kev), 4.24 Mev ($\Gamma =27\mathrm{}$ kev), 4.61 Mev ($\Gamma =140\mathrm{}$ kev), and 4.93 Mev ($\Gamma =106\mathrm{}$ kev). Excitation curves at three angles in the region of 2.9-Mev proton energy show the effect of the previously known $J={\frac{3}{2}}^{-}$ ($\Gamma =80\mathrm{}$ kev) resonance interfering with a level of opposite parity. Effects of the nearby $J={\frac{7}{2}}^{-}$ ($\Gamma =40\mathrm{}$ kev) level are not seen, presumably due to the low penetrability of the outgoing $F$-wave neutron. The thresholds for the second and third neutron groups were investigated using a lithium iodide detector. A new threshold, that for production of the third neutron group, was measured to be 4.910±0.008 Mev in agreement with the known energy of the second excited state in ${\mathrm{N}}^{14}$.

• Received 25 April 1960

DOI:https://doi.org/10.1103/PhysRev.119.1948