The energy levels of ${}^{15}\mathrm{F}$ have been measured by the $p($${}^{14}\mathrm{O}$,$p)$${}^{14}\mathrm{O}$ reaction. The 120 MeV ${}^{14}\mathrm{O}$ radioactive ion beam was produced by the BEARS coupled cyclotron system at an intensity averaging $1\times {10}^4$ particles/second on target. Energy calibration was obtained using resonances from the $p({}^{14}\mathrm{N}$,$p){}^{14}\mathrm{N}$ reaction. The two lowest resonances in ${}^{15}\mathrm{F}$ were fitted with an R-matrix calculation. The fit to the ground state had $J^{\pi }=1/2^{+}$ at 1.23 ± 0.05 MeV (width 0.5 − 0.84 MeV), and the first excited state was $J^{\pi }=5/2^{+}$ at 2.81 ± 0.02 MeV (width 0.30 ± 0.06 MeV), both relative to the mass-energy of the proton and ${}^{14}\mathrm{O}$. The ${}^{15}\mathrm{F}$ ground state energy supports the disappearance of the Z = 8 proton magic number for odd $Z,T_z=-3/2$ nuclei.

• Received 23 June 2005

DOI:https://doi.org/10.1103/PhysRevC.72.034312