Study of theL- andM-Shell X Rays of Pb Produced by 0.5 - 14.0-MeV-Proton Beams

The $L$ and $M$ x rays of Pb were observed with a Si(Li) detector of 190-eV resolution for a 6-keV x-ray line. Absolute shell-ionization cross sections were derived and compared to plane-wave-Born-approximation (PWBA) and binary-encounter-approximation (BEA) predictions. The agreement between theory and experiment was generally good for both cross sections and x-ray ratio predictions. For proton energies less than 3 MeV the $\frac{L\alpha }{L\beta }$ and $\frac{L\alpha }{L\gamma }$ ratios display deviations that are qualitatively predicted by both theories but only absolutely reproduced by the PWBA result for $\frac{L\alpha }{L\beta }$. The $\frac{L\alpha }{\mathrm{Ll}}$ ratio exhibits a minimum in the proton energy range 0.5-3.0 MeV that is not predicted by a single-ionization-state process.