Mass andβdecay of the new isotopeF23: Completion of theTz=+52series of2s−1d-shell masses

The first reported measurements of the $\beta$ decay, half-life, and mass of ${}_{}{}^{23}{}_{}{}^{}\mathrm{F}$ are presented. This isotope is the last of the eight $T_z=+\frac{5}{2}$ nuclei in the $2s-1d$ shell whose masses have been measured and compared to theory. ${}_{}{}^{23}{}_{}{}^{}\mathrm{F}$ was produced by the ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}{}_{}{}^{18}{}_{}{}^{}\mathrm{O}(\alpha ,p){}_{}{}^{23}{}_{}{}^{}\mathrm{F}$ reaction with 42-MeV ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ ions and a target of BeO enriched to 94% in ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$, and was transferred pneumatically to a remotely located station where delayed $\gamma$ rays and $\beta$ rays were counted with Ge(Li) and NE 102 detectors, respectively. $\gamma$-ray energies (in keV) and relative intensities for the ${}_{}{}^{23}{}_{}{}^{}\mathrm{Ne}$ daughter transitions are 492.50 ± 0.57 (10.8 ± 2.8), 815.14 ± 0.53 (24.8 ± 4.7), 1016.62 ± 0.40 (20.1 ± 5.5), 1701.44 ± 0.15 (100 ± 4.7), 1822.25 ± 0.21 (47.4 ± 2.6), 1919.32 ± 0.54 (19.3 ± 2.5), 2129.24 ± 0.39 (68.0 ± 11.4), 2314.70 ± 0.53 (7.7 ± 2.7), 2414.34 ± 0.41 (14.8 ± 3.4), 2516.50 ± 0.51 (2.9 ± 1.0), 2734.48 ± 0.44 (11.9 ± 1.6), 3431.28 ± 0.35 (25.4 ± 1.6), and 3830.52 ± 0.36 (6.8 ± 0.9). The strongest observed $\beta$ branch populates a previously unreported state in ${}_{}{}^{23}{}_{}{}^{}\mathrm{Ne}$ at 3831-keV excitation energy. The ${}_{}{}^{23}{}_{}{}^{}\mathrm{Ne}$ excitation energies (in keV) and relative β-branching intensities are 0 (<6250), 1016.64 ± 0.40 (<4.6), 1701.51 ± 0.15 (<3.8), 1822.33 ± 0.21 (14.4 ± 1.8), 2314.84 ± 0.53 (9.6 ± 2.0), 2516.65 ± 0.51 (4.7 ± 2.8), 3220.7 ± 0.7 (<1.2), 3431.55 ± 0.35 (21.9 ± 2.1), 3830.86 ± 0.36 (34.9 ± 5.3), 3836.9 ± 0.7 (<1.1), and 4435.99 ± 0.41 (14.5 ± 1.3). $\gamma$-ray branching ratios for several states in ${}_{}{}^{23}{}_{}{}^{}\mathrm{Ne}$ are presented, and the half-life of ${}_{}{}^{23}{}_{}{}^{}\mathrm{F}$ is 2.23 ± 0.14 sec. By measuring the energy spectra of $\beta$ rays coincident with each of the 1702-, 1822-, 2734-, and 3432-keV $\gamma$ rays, the mass excess of