Decay ofCs125,Cs127, andCs129

Neutron-deficient isotopes of cesium (${}_{}{}^{129}{}_{}{}^{}\mathrm{Cs}$, ${}_{}{}^{127}{}_{}{}^{}\mathrm{Cs}$, and ${}_{}{}^{125}{}_{}{}^{}\mathrm{Cs}$) were produced by the $\alpha$-particle bombardment of natural iodine. $\gamma$-ray energies and intensities were measured with Ge (Li) detectors. In the decay of 32-h ${}_{}{}^{129}{}_{}{}^{}\mathrm{Cs}$, among others, 372- and 582-keV $\gamma$ rays were detected. In the decay of 6.2-h ${}_{}{}^{127}{}_{}{}^{}\mathrm{Cs}$, new $\gamma$ rays have been detected, and new levels at 1430, 1805, and 1829 keV have been proposed. In the decay of 45-min ${}_{}{}^{125}{}_{}{}^{}\mathrm{Cs}$, the following levels in ${}_{}{}^{125}{}_{}{}^{}\mathrm{Xe}$ (percentage feeding in parentheses) have been proposed: ground state (54%), 112 keV (2%), 526 keV (30%), 540 keV (4%), 712 keV (6%), 1311 keV (0.33%), 1326 keV (0.43%), 1579 keV (0.5%), 1698 keV (0.7%), 2154 keV (0.2%), 2523 keV (0.2%), and 2545 keV (0.1%). These decay schemes show that the $\beta$ decay of these cesium isotopes takes place preferentially to the excited states in the daughter xenon isotopes.