L Subshell Ionization Cross Sections of Pr, Sm, Tb, Ho, and Yb for 150-400 KeV Protons

Thick target x-ray yields of Pr, Sm, Tb, Ho, and Yb have been measured for incident protons in the energy range of 150-400 keV. Yields of the L¿12, L¿1, and L¿23 transitions were first converted into x-ray cross sections, then to L-subshell ionization cross sections by the use of theoretical Coster-Kronig decay rates, fluorescence yields, and radiative decay rates. The resultant L-subshell ionization cross sections are found to be in reasonable agreement with the perturbed stationary-state theory as applied to the L shell by Brandt and Lapicki when allowance is made for relativistic effects.