The decay schemes of ${}_{}{}^{129}{}_{}{}^{}\mathrm{Cs}$ and ${}_{}{}^{133}{}_{}{}^{}\mathrm{I}$ have been studied in order to extend the detailed level properties of odd-mass Xe. For ${}_{}{}^{129}{}_{}{}^{}\mathrm{Cs}$, decay levels in ${}_{}{}^{129}{}_{}{}^{}\mathrm{Xe}$ are identified at ($J^{\pi }$ values in parentheses) ground state ($\left({\frac{1}{2}}^{+}\right)$), $39.57 \left({\frac{3}{2}}^{+}\right)$, $236.14 \left({\frac{11}{2}}^{-}\right)$, $\left({\frac{3}{2}}^{+}\right)$, $321.70 \left({\frac{5}{2}}^{+}\right)$, $411.49 \left({\frac{1}{2}}^{+}\right)$, $572.67 \left({\frac{5}{2}}^{+}\right)$, $588.55 \left({\frac{3}{2}}^{+}\right)$, $624.32 \left({\frac{7}{2}}^{+}\right)$, $904.31 \left({\frac{1}{2}}^{+}\right)$, and 946.03 keV ($\left({\frac{3}{2}}^{+}\right)$); for ${}_{}{}^{133}{}_{}{}^{}\mathrm{I}$, decay levels in ${}_{}{}^{133}{}_{}{}^{}\mathrm{Xe}$ are identified at ground state ($\left({\frac{3}{2}}^{+}\right)$), $233.22 \left({\frac{11}{2}}^{-}\right)$, $262.70 \left({\frac{1}{2}}^{+}\right)$, $529.87 \left({\frac{5}{2}}^{+}\right)$, $680.24 \left({\frac{3}{2}}^{+}\right)$, $743.75 ({\frac{9}{2}}^{-},{\frac{7}{2}}^{-})$, $875.32 \left({\frac{7}{2}}^{+}\right)$, $911.46 \left({\frac{3}{2}}^{+}\right)$, $1052.29 \left({\frac{5}{2}}^{+}\right)$, $1236.44 \left({\frac{7}{2}}^{+}\right)$, $1298.22 \left({\frac{5}{2}}^{+}\right)$, $1350.32 \left({\frac{5}{2}}^{+}\right)$, $1386.15 \left({\frac{7}{2}}^{+}\right)$, and 1589.92 keV ($({\frac{7}{2}}^{+},{\frac{5}{2}}^{+})$). Gas chromatography techniques were used to determine a branching ratio of (2.88 ± 0.02)% of all ${}_{}{}^{133}{}_{}{}^{}\mathrm{I}$ decays populating the ${}_{}{}^{133}{}_{}{}^{}\mathrm{Xe}{\frac{11}{2}}^{-}$ isomer. These levels and their properties are compared with other odd-mass Xe nuclei and their level properties.

RADIOACTIVITY ${}_{}{}^{129}{}_{}{}^{}\mathrm{Cs}$ (mass separated) ${}_{}{}^{133}{}_{}{}^{}\mathrm{I}$ (chemically isolated from fission) measured $E_{\gamma }$, $I_{\gamma }$, $\gamma -\gamma$ coin; deduced $log\mathrm{ft}$. ${}_{}{}^{129}{}_{}{}^{}\mathrm{Xe}$ and ${}_{}{}^{133}{}_{}{}^{}\mathrm{Xe}$ deduced levels, $J$, $\pi$.

• Received 17 November 1975

DOI:https://doi.org/10.1103/PhysRevC.14.1152