Reinvestigation ofCs132Decay

There has been some disagreement in the literature as to the properties of the low-lying states in ${}_{}{}^{132}{}_{}{}^{}\mathrm{Xe}$, and in particular as to the energy of the second excited state of this nucleus. The decay of ${}_{}{}^{132}{}_{}{}^{}\mathrm{Cs}$ has been reinvestigated by use of $p-i-n$ lithium-drifted germanium detectors having high resolution, and it is found that the first and second excited states in ${}_{}{}^{132}{}_{}{}^{}\mathrm{Xe}$ are depopulated by transitions with respective energies of 668.8±1.0 and 630.7±1.5 keV. In addition, gamma rays were also observed with the germanium detectors at energies of 464±3, 507±3, 511±3, 773±5, 1037±3, 1140±1.2, 1233±3, 1300.0±1.5, 1320.0±1.5, and 1985±5 keV. Gamma-gamma (NaI) coincidence measurements, made with a 100- by 200-channel multiparameter analyzer, revealed several new features of the decay. The excited levels observed in ${}_{}{}^{132}{}_{}{}^{}\mathrm{Xe}$ are at 668.8±1.0, 1299.5±2.0, 1442±3, 1808.3±2.2, and 1988.8±2.5 keV. Levels at 464±3 and 1037±3 keV in ${}_{}{}^{132}{}_{}{}^{}\mathrm{Ba}$ are also populated.