We have studied the decay of 33-day ${}_{}{}^{129}{}_{}{}^{}\mathrm{Te}_{}^m{}_{}{}^{}$ and 70-min ${}_{}{}^{129}{}_{}{}^{}\mathrm{Te}_{}^g{}_{}{}^{}$ with high resolution Ge(Li) detectors used both singly and in coincidence. Sources of ${}_{}{}^{129}{}_{}{}^{}\mathrm{Te}_{}^m{}_{}{}^{}$ and ${}_{}{}^{129}{}_{}{}^{}\mathrm{Te}_{}^g{}_{}{}^{}$ in equilibrium were used as well as sources of ${}_{}{}^{129}{}_{}{}^{}\mathrm{Te}_{}^g{}_{}{}^{}$ containing less than 0.0003 parts ${}_{}{}^{129}{}_{}{}^{}\mathrm{Te}_{}^m{}_{}{}^{}$ activity. Fifty $\gamma$ rays resulting from ${}_{}{}^{129}{}_{}{}^{}\mathrm{Te}_{}^g{}_{}{}^{}$ decay and 39 $\gamma$ rays from ${}_{}{}^{129}{}_{}{}^{}\mathrm{Te}_{}^m{}_{}{}^{}$ decay have been assigned to levels in ${}_{}{}^{129}{}_{}{}^{}\mathrm{I}$. This work establishes new levels in ${}_{}{}^{129}{}_{}{}^{}\mathrm{I}$ at 1047.44 (${3/2}^{+}$), 1203.7 (${7/2}^{+}$), 1209.9 (${1/2}^{+}$), and 1282.00 (${7/2}^{+}$) keV ($J^{\pi }$ in parentheses). In conjunction with recent (${}_{}{}^3{}_{}{}^{}\mathrm{He},d$) and angular distribution work several other new or more reliable spin-parity assignments can be made as follows: 845 (${9/2}^{+}$), 1112 (${5/2}^{+}$), 1261 (${5/2}^{+}$), 1292 (${3/2}^{+}$), and 1401 (${11/2}^{-}$). The data are discussed in terms of the particle or quasiparticle phonon model and the three-particle cluster model.

RADIOACTIVITY ${}_{}{}^{129}{}_{}{}^{}\mathrm{Te}$ [from ${}_{}{}^{128}{}_{}{}^{}\mathrm{Te}_{}^m{}_{}{}^{}(n,\gamma )$]; measured $E_{\gamma }$, $I_{\gamma }$, $\gamma \gamma$ coin; deduced $log\mathrm{ft}$. ${}_{}{}^{129}{}_{}{}^{}\mathrm{I}$ deduced levels $E$, $J$, $\Pi$; $B \mathrm{}\left(E2\mathrm{}\right)\mathrm{}$. Ge(Li) detectors, enriched ${}_{}{}^{128}{}_{}{}^{}\mathrm{Te}$ targets.

• Received 17 May 1976

DOI:https://doi.org/10.1103/PhysRevC.14.1141