Ultrahigh-resolution (436-eV full width at half-maximum at 14.4 keV) Ge(Li) and Si(Li) x-ray detectors have been used to investigate $L$ x rays of Bi from the decay of carrier-free ${\mathrm{Pb}}^{210}$ ($\mathrm{Ra}D$). A detailed study of the detection efficiencies was carried out, in order to take into account effects due to Ge $K$ x-ray escape, and absorption in layers of inactive Ge or Si, Au, Al, and Be present between the source and active detector volume. A DuPont curve-resolving analog computer was used to resolve the $L$ x-ray spectrum into further components. The resolved spectra thus yielded 10 $L$ x-ray groups, together with their absolute intensities in ${\mathrm{Pb}}^{210}$ decay. Combining these results with recent precision $L$-conversion and $L$ Auger electron absolute intensities in this decay, the following set of $L$-subshell fluorescence yields (${\omega }_i$), Auger yields ($a_i$), and Coster-Kronig transition probabilities ($f_{\mathrm{ij}}$) are obtained: ${\overline{\omega }}_L=0.330\mathrm{}\pm 0.016$, ${\omega }_3=0.345\mathrm{}\pm 0.018$, and ${\omega }_1=0.095\mathrm{}\pm 0.005$; ${\overline{a}}_L=0.670\mathrm{}\pm 0.016$, $a_3=0.655\mathrm{}\pm 0.018$, and $a_1=0.133\mathrm{}\pm 0.009$; and $f_{12}+f_{13}=0.772\mathrm{}\pm 0.011$. Using the recent value of $f_{23}=0.164\mathrm{}\pm 0.016$ at $Z=82\mathrm{}$, determined by Rao et al., the following additional quantities are evaluated: ${\omega }_2=0.23\mathrm{}\pm 0.02$, $a_2=0.61\mathrm{}\pm 0.02$, $f_{12}=0.18\mathrm{}\pm 0.02$, and $f_{13}=0.58\mathrm{}\pm 0.02$. A remarkably strong $E2\mathrm{}$ $L$ x-ray transition ($L_1-M_{4,5}$) also was observed in the decay of ${\mathrm{Pb}}^{210}$ ($\mathrm{Ra}D$).

• Received 6 September 1968

DOI:https://doi.org/10.1103/PhysRev.178.1952