Decay ofSb124toTe124

Abstract

The $\gamma$ rays from 60-day ${}_{}{}^{124}{}_{}{}^{}\mathrm{Sb}$ have been measured with a Ge $\gamma$-ray detector. $\gamma -\gamma$ coincidence and correlation measurements were made with a Ge detector and a NaI scintillation detector. $\beta -\gamma$ coincidences were made using a Ge detector and anthracene scintillation detector. The Ge detector was placed in a large NaI annulus detector to provide both anticoincidence Compton-suppressed spectra and high-resolution $\gamma$-ray pair spectra. A total of 25 $\gamma$ rays were observed. A level scheme is proposed which contains 13 levels. Angular-correlation measurements (a) confirm a spin-4 assignment to the 1247.6-keV state and (b) show that the spin of the 1325.0-keV state is 2 and that the 722.5-keV $\gamma$ ray to the first $2^{+}$ state has a mixture $\delta \equiv {\left(\frac{E^2}{M1\mathrm{}}\right)}^{\frac{1}{2}}=3.4\mathrm{}\pm 0.6$. Two levels at 1956.5 and 2038 keV have properties which are consistent with a three-phonon collective-state interpretation.