Recent Experimental Results on Orbital Electron Capture

A summary is presented of experimental techniques and experimental results on electron-capture ratios, comparative half-lives, and transition energies. The effect of electron capture from the $M$ shell and higher shells is taken into account. Transition energies are computed from the observed capture ratios for about twenty cases. A summary of mean $L$-fluorescence yields following nuclear excitation is brought up to date, and the origins of uncertainties in the interpretation of experimental results are discussed.

Six experiments are precise enough to be compared critically with the theory of Brysk and Rose, and the observed $\frac{L}{K}$ capture ratios are found to be some ten percent greater than predicted. The discrepancies seem to be more or less independent of atomic number for $18<~Z<~53$; it is not at all clear that the effect of correlations between the coordinates of the $K$ electrons, suggested by Odiot and Daudel, is sufficient to account for the discrepancy.