On-Line Spectroscopy ofI134m,g

Sources of mass-134 iodine have been produced in ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$ fission and studied on line in the Buenos Aires Isotope Separator On Line project using Ge(Li) and Si(Li) detectors. A transition of 272.2 ± 0.3 keV, with $T_{\frac{1}{2}}=3.56\mathrm{}\pm 0.08$ min, ${\alpha }_K=0.20\mathrm{}\pm 0.03$, and $\frac{K}{L}+\cdots =2.6\mathrm{}\pm 0.3$, thus $E3(+\le 1\%M4)$ in character, was determined to be the transition depopulating the isomeric state in ${}_{}{}^{134}{}_{}{}^{}I(E_L-E_K=28.4\mathrm{}\pm 0.2 \mathrm{keV} \mathrm{and} K \mathrm{binding} \mathrm{energy}=32.9\mathrm{}\pm 0.6 \mathrm{keV})$. The $\beta$ branching from this isomeric state to levels of ${}_{}{}^{134}{}_{}{}^{}\mathrm{Xe}$ amounts to (8 ± 6)%. $\gamma$-ray intensities following the ground-state decay of ${}_{}{}^{134}{}_{}{}^{}I(T_{\frac{1}{2}}=53.2\mathrm{}\pm 0.2 min)$ are given. Internal-conversion coefficients for 11 transitions have been measured (${10}^4{\alpha }_K$): 135 keV, 2600±500; 188 keV, 1300±500; 236 keV, 700±100; 406 keV, 110±20; 433 keV, 150±30; 541 keV, 60±8; 596 keV, 70±8; 622 keV, 52±8; 628 keV, 25±19; 847 keV, 18±3; and 884 keV, 19±4. Parities and angular momenta for levels of ${}_{}{}^{134}{}_{}{}^{}\mathrm{Xe}$ are proposed.