Energy spectra of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ ions from the ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}(t,{}_{}{}^3{}_{}{}^{}\mathrm{He}){}_{}{}^{18}{}_{}{}^{}\mathrm{N}$ and the ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}(t,{}_{}{}^3{}_{}{}^{}\mathrm{He}){}_{}{}^{22}{}_{}{}^{}\mathrm{F}$ reactions have been measured for a triton bombarding energy of 22 MeV. A proportional $\Delta E$ detector and a silicon $E$-detector were used to identify and measure the energy of the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ ions. From $Q$-value determinations, ground-state mass excesses (${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$=O) were found to be 13.274±0.030 MeV for ${}_{}{}^{18}{}_{}{}^{}\mathrm{N}$ and 2.828±0.030 MeV for ${}_{}{}^{22}{}_{}{}^{}\mathrm{F}$. The ${}_{}{}^{22}{}_{}{}^{}\mathrm{F}$ mass value is 1.67 MeV lower than the only previously reported value. Other groups in the spectra correspond to the first observation of excited states in ${}_{}{}^{22}{}_{}{}^{}\mathrm{F}$. Excitation-energy values for these six excited states are 0.66, 1.36, 1.57, 1.97, 2.54, and 2.91 MeV. Also, spectra from the ($p,p^{\prime }$), ($d,d^{\prime }$), and ($t,t^{\prime }$) reactions were measured with a ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}$ target to search for $T=2\mathrm{}$ analogs to ${}_{}{}^{22}{}_{}{}^{}\mathrm{F}$ states. Groups which appeared only in the ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}(p,p^{\prime })$ and ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}(t,t^{\prime })$ spectra have Coulomb-energy shifts and widths which suggest that they are analogs to the ground, second, third, and fourth excited states of ${}_{}{}^{22}{}_{}{}^{}\mathrm{F}$. Based on the measured values of the ${}_{}{}^{18}{}_{}{}^{}\mathrm{N}$ and ${}_{}{}^{22}{}_{}{}^{}\mathrm{F}$ ground-state masses and the systematics of pairing energy, estimates are made for the masses of the unreported nuclei ${}_{}{}^{22}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{19}{}_{}{}^{}\mathrm{N}$, ${}_{}{}^{21}{}_{}{}^{}\mathrm{O}$, and ${}_{}{}^{23}{}_{}{}^{}\mathrm{F}$. The last three nuclei are predicted to be stable against neutron decay, whereas ${}_{}{}^{22}{}_{}{}^{}\mathrm{Al}$ is estimated to be near the limit of proton stability.

• Received 17 June 1968

DOI:https://doi.org/10.1103/PhysRev.178.1789