Decay ofCs132

Abstract

The singles and coincidence gamma-ray spectra of ${\mathrm{Cs}}^{132}$ have been investigated with scintillation spectrometers. Energies in keV (and relative intensities) of the gamma rays which were observed are 464(21±5), 509(5.1±1.5), 511(12±4), 569(2.7±0.8), 631(8.5±1.8), 669(1000±30), 1035(1.6±0.3), 1139(5.2±0.5), 1304(0.9±0.5), 1319(6.2±0.6), and 2000(0.53±0.06). From the results of these spectral studies and from gamma-gamma angular correlation measurements, it is proposed that ${\mathrm{Cs}}^{132}$ decays to levels with energies in keV (and spins) of 669±4(2+), 1300±10(2+), 1808±13(2 or 3), and 1988±12(2) in ${\mathrm{Xe}}^{132}$, and 464±5(2+) and 1034±9(2+) in ${\mathrm{Ba}}^{132}$. The ratios of the intensities of quadrupole to dipole radiation for the 631- and 1319-keV transitions in ${\mathrm{Xe}}^{132}$ and for the 569-keV transition in ${\mathrm{Ba}}^{132}$ were found to be 10,0.006, and ≥200, respectively. The predominantly quadrupole character of the transitions between the second and first spin 2 levels is attributed to the collective behavior of the nuclei. From the ratio of decay by electron capture and by positron emission to the 669-keV level, the energy separation between ${\mathrm{Cs}}^{132}$ and ${\mathrm{Xe}}^{132}$ was estimated to be 2.15 MeV.