Absoluteγ-ray intensities in the decay ofKr79andXe127

Absolute $\gamma$-ray intensities in the decay of ${}_{}{}^{79}{}_{}{}^{}\mathrm{Kr}$ and ${}_{}{}^{127}{}_{}{}^{}\mathrm{Xe}$ have been determined from sources which were produced by ($p,n$) reactions on encapsulated potassium-halide targets. Absolute $\gamma$-ray emission rates of these sources were first measured with several calibrated Ge(Li)-detector systems. Then, following separation of the ${}_{}{}^{79}{}_{}{}^{}\mathrm{Kr}$ or ${}_{}{}^{127}{}_{}{}^{}\mathrm{Xe}$ gas, absolute disintegration rates of the sources were obtained by counting internally in gas proportional counters. Comparisons of the present results with previous work are made and although there are no major discrepancies, several inconsistencies in the existing decay schemes are resolved and the uncertainties in the absolute $\gamma$-ray intensities are substantially reduced. The half-lives for ${}_{}{}^{79}{}_{}{}^{}\mathrm{Kr}$ and ${}_{}{}^{127}{}_{}{}^{}\mathrm{Xe}$ were measured by both gas proportional counting and $\gamma$-ray spectrometry and are 35.04±0.10 h and 36.3±0.3 day, respectively.