High-Resolution Gamma-Ray Spectroscopic Study of the DecayBa133→Cs133

Abstract

The decay of ${}_{}{}^{133}{}_{}{}^{}\mathrm{Ba}$ to levels in ${}_{}{}^{133}{}_{}{}^{}\mathrm{Cs}$ was studied using Ge(Li) $\gamma$-ray spectrometers. The energies of the measured $\gamma$-ray transitions are 53.14(8), 160.68(10), 223.08(10), 276.45(8), 302.87(8), 355.99(7), and 383.92(7) keV. The corresponding relative $\gamma$-ray intensities of these transitions are 3.16(39), 0.99(10), 0.72(8), 11.62(82), 29.4(21), 100, and 14.3(10). $\gamma$-ray spectra in coincidence with the 53.1-, 79.6-, 81.0-, 276.4-, 302.9-, 356.0-, and 383.9-keV $\gamma$ rays were obtained. The data are in quantitative agreement with the existing decay scheme. The $K$-shell internal-conversion coefficients were determined, using the present $\gamma$-ray relative intensities and published $K$-shell internal-conversion-electron relative intensities. These results and earlier lifetime measurements and mixing ratios were used to calculate $\gamma$-ray-transition retardation and enhancement factors.