The level scheme of even-even ${}_{}{}^{134}{}_{}{}^{}\mathrm{Ba}$ has been studied from the decay of the ${}_{}{}^{134}{}_{}{}^{}\mathrm{Ce}$ (75.9 h)→${}_{}{}^{134}{}_{}{}^{}\mathrm{La}$ (6.67 min) chain. Samples of ${}_{}{}^{134}{}_{}{}^{}\mathrm{Ce}$ were produced by ∼800-MeV proton bombardment of Pr foils, followed by chemical and mass separation. $\gamma$-ray energy and intensity measurements were made using Ge(Li) and Si(Li) detectors. Identification of $\gamma$ rays as belonging to the ${}_{}{}^{134}{}_{}{}^{}\mathrm{La}$ decay was made in separate experiments using sources of ${}_{}{}^{134}{}_{}{}^{}\mathrm{La}$ milked from the parent ${}_{}{}^{134}{}_{}{}^{}\mathrm{Ce}$ activity. In this manner, ∼99$\gamma$-ray transitions have been associated with the ${}_{}{}^{134}{}_{}{}^{}\mathrm{La}$ decay scheme. From these data and $\gamma -\gamma$ coincidence measurements, a comprehensive level scheme is proposed for ${}_{}{}^{134}{}_{}{}^{}\mathrm{Ba}$, consisting of ∼41 excited states. Further information on the energies of levels in ${}_{}{}^{134}{}_{}{}^{}\mathrm{Ba}$ was derived from a subsidiary series of $\gamma$-ray energy measurements using a source of ${}_{}{}^{134}{}_{}{}^{}\mathrm{Cs}$. For the ${}_{}{}^{134}{}_{}{}^{}\mathrm{La}$ decay, $log\mathrm{ft}$ values were obtained from relative x-ray, annihilation-quanta, and $\gamma$-ray intensities and using intensity-balance considerations for the individual levels in ${}_{}{}^{134}{}_{}{}^{}\mathrm{Ba}$. A comparison is made of the ${}_{}{}^{134}{}_{}{}^{}\mathrm{Ba}$ data with the predictions of several recent theoretical calculations dealing with even-even nuclei in this mass region.

RADIOACTIVITY ${}_{}{}^{134}{}_{}{}^{}\mathrm{La}$ from $\mathrm{Pr}\left[\right(p, \mathrm{spallation}\left)\right]$; measured $E_{\gamma }$, $I_{\gamma }$, $\gamma -\gamma$; ${}_{}{}^{134}{}_{}{}^{}\mathrm{Cs}$ deduced levels, $J$, $\pi$, $log\mathrm{ft}$. Ge(Li) and Si(Li) detectors, chemical separation, isotope separations. ${}_{}{}^{134}{}_{}{}^{}\mathrm{Cs}$; measured $E_{\gamma }$.

• Received 24 May 1976

DOI:https://doi.org/10.1103/PhysRevC.14.1906