Double Vacancies in theKShell Associated withK-Electron Capture inA37

The pulse-height spectrum produced by the decay of ${\mathrm{A}}^{37}$ in a proportional counter was analyzed to determine the probability, per $K$-electron capture, for the production of a double vacancy in the $K$ shell. The double vacancy is produced by promotion of the second $K$ electron to a bound state or to the continuum. In these experiments both processes could be observed; the measurements included events in which the kinetic energies of the promoted electrons were in the range zero to 4.0 kev. Seventy-three percent of the theoretically predicted total effect should occur in this energy interval. The data, appropriately corrected, give for the probability of double $K$-vacancy production per $K$ capture, in the energy interval investigated, 3.9±0.7×${10}^{-4\mathrm{}}$. The result is substantially in agreement with the value calculated from theory.