Electron-Capture Decay ofBi207:L-Subshell Fluorescence Yields and Coster-Kronig Transition Probabilities of Pb

Abstract

Coincidence spectrometry with high-resolution Si(Li) and Ge(Li) x-ray spectrometers (resolutions 470-eV full width at half-maximum at 14.4 keV) has been employed to study directly the x rays emitted during the filling of each of the three $L$-subshell primary vacancies in the electron-capture decay of ${\mathrm{Bi}}^{207}$. The $L$ x rays, observed in the Si(Li) detector, in fast coincidence ($2\tau =110\mathrm{}$ nsec) with $K_{\alpha 1}$ x rays detected in the Ge(Li) detector, arise entirely from initial vacancies in the $L_3$ subshell, while those in coincidence with $K_{\alpha 2}$ x rays are from initial $L_2$-subshell vacancies. The clear presence of $L_{\alpha }$ x rays, which arise only from $L_3$ vacancies, in the latter spectrum indicates that Coster-Kronig transitions of the type $L_2-L_{3}X$ take place. The $L$ x rays in coincidence with 1770-, 1063-, and 570-keV $\gamma$ rays and with 1063-keV $L$-conversion electrons give information on $L_1$-subshell quantities. The following results are obtained: ${\omega }_3=0.315\mathrm{}\pm 0.013$, ${\omega }_2=0.363\mathrm{}\pm 0.015$, ${\omega }_1=0.07\mathrm{}\pm 0.02$, ${\nu }_1=0.295\mathrm{}\pm 0.010$, ${\nu }_2=0.417\mathrm{}\pm 0.015$, $f_{12}=0.15\mathrm{}\pm 0.04$, $f_{13}=0.57\mathrm{}\pm 0.03$, and $f_{23}=0.164\mathrm{}\pm 0.016$ at $Z=82\mathrm{}$.