K-shell internal-ionization probabilities in nuclearβ−decay

Total $K$-shell internal-ionization probabilities have been determined by x-ray spectroscopy with a high-energy-resolution Si(Li) detector for the ${\beta }^{-}$-decaying isotopes ${}_{}{}^{45}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{89}{}_{}{}^{}\mathrm{Sr}$, ${}_{}{}^{90}{}_{}{}^{}\mathrm{Sr}$, ${}_{}{}^{90}{}_{}{}^{}\mathrm{Y}$, ${}_{}{}^{99}{}_{}{}^{}\mathrm{Tc}$, ${}_{}{}^{147}{}_{}{}^{}\mathrm{Pm}$, and ${}_{}{}^{185}{}_{}{}^{}\mathrm{W}$. The number of emitted $K$ x rays were measured in comparison to the absolute ${\beta }^{-}$-decay rate. The results are compared with earlier experimental values and recent theoretical calculations of Law and Campbell. Good agreement is found between theory and experiment.