Proton ionization of theLsubshells of Pr, Eu, Gd, and Dy: 0.3 to 2.0 MeV

Total $L$-shell ionization cross sections were measured for Pr, Eu, Gd, and Dy over the energy range 0.3-0.2 MeV and compared to the nonrelativistic plane-wave Born approximation (PWBA), the constrained binary-encounter approximation (CBEA), and the binary-encounter approximation. Both the PWBA and CBEA predicted the measured values. Also the $\frac{L{\alpha }_{1,2}}{\mathrm{Ll}}$, $\frac{L{\alpha }_{1,2}}{L{\gamma }_1}$, $\frac{L{\alpha }_{1,2}}{L{\gamma }_{2,3}}$, and $\frac{L{\gamma }_1}{L{\gamma }_{2,3}}$ ratios were measured and compared with PWBA and CBEA. The results showed that the CBEA and PWBA accurately predicted the $L_{\mathrm{II}}$- and $L_{\mathrm{III}}$-subshell ionization cross sections, while only the PWBA accurately predicted the $L_{\mathrm{I}}$-subshell ionization cross section.