Study of theL-shell x rays of Ta, Pt, Au, Hg, and Pb by proton bombardment

The $L$ x-ray transition ratios $L\left(\frac{{\alpha }_{12}}{l}\right)$, $L\left(\frac{{\gamma }_1}{\eta }\right)$, $L\left(\frac{\eta }{{\gamma }_5}\right)$, $L\left(\frac{{\gamma }_{236}}{{\gamma }_1}\right)$, and $L\left(\frac{{\gamma }_{{44}^{\prime }}}{{\gamma }_1}\right)$ have been measured for the elements ${}_{}{}^{73}{}_{}{}^{}\mathrm{T}\mathrm{a},$ ${}_{}{}^{78}{}_{}{}^{}\mathrm{P}\mathrm{t},$ ${}_{}{}^{79}{}_{}{}^{}\mathrm{A}\mathrm{u},$ ${}_{}{}^{80}{}_{}{}^{}\mathrm{H}\mathrm{g},$ and ${}_{}{}^{82}{}_{}{}^{}\mathrm{Pb}$ by ionization of the $L$-subshell electrons with 0.4-2.0-MeV proton bombardment. Transition-rate ratios $L\left(\frac{{\gamma }_{23}}{{\gamma }_{{44}^{\prime }}}\right)$ to the $L_1$ subshell, $L\left(\frac{{\gamma }_6}{{\gamma }_1}\right)$, $L\left(\frac{{\gamma }_1}{\eta }\right)$, and $L\left(\frac{\eta }{{\gamma }_5}\right)$ to the $L_2$ subshell, and $L\left(\frac{{\alpha }_{12}}{l}\right)$ to the $L_3$ subshell have been extracted. Comparison of the extracted ratios with the relativistic Hartree-Fock model calculations of Scofield shows agreement within experimental errors for the $L_1$, $L_2$, and $L_3$ subshell ratios. A previously reported minimum in the Pb $L\left(\frac{{\alpha }_{12}}{l}\right)$ ratio between proton energies 1.0 to 1.5 MeV was not observed. Total $L$-shell production cross sections have also been measured for Pt and Au over the energy range 0.4-2.0 MeV and are found to be in good agreement with the predictions of the nonrelativistic plane-wave Born approximation and the constrained binary-encounter approximation, but not with the binary-encounter approximation.