Beta Decay ofNe24

The $\beta$ decay of ${\mathrm{Ne}}^{24}$ has been studied by observing the delayed $\gamma$-ray spectrum with the aid of a Ge(Li) $\gamma$-ray spectrometer. ${\mathrm{Ne}}^{24}$ was produced by the ${\mathrm{Ne}}^{22}(t, p){\mathrm{Ne}}^{24}$ reaction, at an incident bombarding energy of 2.5 MeV. Two strong $\gamma$ rays attributable to the $\beta$ decay of ${\mathrm{Ne}}^{24}$ were observed, with energies $E_{\gamma }=472.2\mathrm{}\pm 0.2 \mathrm{and} 874.3\pm 0.3$ keV; these are assigned to the 0.472→0 and 1.347→0.472 transitions in ${\mathrm{Na}}^{24}$, respectively. Both $\beta$-decay modes are allowed; thus $J^{\pi }={(0, 1)}^{+}$ for the ${\mathrm{Na}}^{24}$ 0.472- and 1.347-MeV levels. For both these levels, the spin-parity assignment $J^{\pi }=1^{+}$ follows immediately from the allowed nature of the $\beta$ transitions and the isotopic spin selection rule: If $\Delta T=1\mathrm{}$, the $0^{+}$→$0^{+}$ $\beta$ transition is forbidden. The spin-parity of the 1.347-MeV level had previously been unknown.