Mass andβDecay ofNe25, aTz=+52Nuclide

Abstract

The first reported measurement of the delayed $\gamma$-ray spectrum following the $\beta$ decay of ${}_{}{}^{25}{}_{}{}^{}\mathrm{Ne}$ is presented. ${}_{}{}^{25}{}_{}{}^{}\mathrm{Ne}$ recoils from the ${}_{}{}^9{}_{}{}^{}\mathrm{Be}({}_{}{}^{18}{}_{}{}^{}\mathrm{O},2p){}_{}{}^{25}{}_{}{}^{}\mathrm{Ne}$ reaction were thermalized in He gas and transferred through traps to a remotely located counting station. $\gamma$ and $\beta$ rays were counted simultaneously with Ge(Li) and NE102 detectors, respectively. $\gamma$-ray energies (in keV) and relative intensities for the ${}_{}{}^{25}{}_{}{}^{}\mathrm{Na}$ daughter transitions are 89.53 ± 0.10 (95.5 ± 0.6), 979.77 ± 0.16 (18.1 ± 1.9), 1069.30 ± 0.19 (2.34 ± 0.38), 2112.5 ± 1.0 (0.62 ± 0.19), 2202.0 ± 1.0 (1.1 ± 0.3), and 3688 ± 3 (0.96 ± 0.24). The ground-state $\beta$ branch has been measured to be less than 20% of all $\beta$ branches. The ${}_{}{}^{25}{}_{}{}^{}\mathrm{Na}$ excitation energies (in keV) and $\beta$ branches (in%, assuming the ground-state branch is zero) are 89.53 ± 0.10 (76.8 ± 1.9), 1069.32 ± 0.19 (19.2 ± 2.0), 2202 ± 1 (2.3 ± 0.5), and 3688 ± 3 (1.18 ± 0.30). A 0.52 ± 0.15% branch is tentatively assigned to a state in ${}_{}{}^{25}{}_{}{}^{}\mathrm{Na}$ at 4289 ± 3 keV, on the basis of an observed 3220 ± 3-keV $\gamma$ ray. The half-life of ${}_{}{}^{25}{}_{}{}^{}\mathrm{Ne}$ has been measured to be 602 ± 8 msec. By measuring the end-point energy of the $\beta$ spectrum populating the first excited state of ${}_{}{}^{25}{}_{}{}^{}\mathrm{Na}$ the mass excess of ${}_{}{}^{25}{}_{}{}^{}\mathrm{Ne}$ has been measured to be -1.96 ± 0.30 MeV. Comparison of the mass and decay of ${}_{}{}^{25}{}_{}{}^{}\mathrm{Ne}$ with theoretical estimates and models is made.