Decay ofNa25

Abstract

${\mathrm{Na}}^{25}$ was produced in the ${\mathrm{Na}}^{23}\mathrm{}(t,p)\mathrm{}{\mathrm{Na}}^{25}$ reaction and its radiations were investigated by means of Ge(Li), plastic, and NaI(Tl) detectors. From $\beta -\gamma$ coincidence experiments the ${\mathrm{Na}}^{25}$ $\beta$-ray branch to the ground state of ${\mathrm{Mg}}^{25}$ is 62.5±2.0%. Other $\beta -$ and $\gamma$-ray branches were derived from the $\gamma$-ray spectrum and are in agreement with previous results. From both singles and $\gamma -\gamma$ coincidence measurements a limit of <0.02% ($log\mathrm{ft}>\mathrm{}6.5\mathrm{}$) is placed on the $\beta$-ray branch to the 2738-keV $J^{\pi }={\frac{7}{2}}^{+}$ state of ${\mathrm{Mg}}^{25}$. Recent shell-model calculations give a good account of the relative experimental $\beta$-branching intensities and, in particular, predict that the transition to the 2738-keV state should be very weak.