L -subshell ionization by proton and alpha-particle bombardment of Ta, Au, and Bi

Cross sections for ionization of the LI, LII, and LIII subshells in Ta, Au, and Bi have been measured for proton energies from 1.0 to 5.5 MeV and α-particle energies from 1.0 to 11.0 MeV. X-ray spectra recorded with a Si(Li) detector were used to deduce the subshell ionization cross sections: Lα components give LIII subshell ionization cross sections σ_L₃, and Lγ components were computer analyzed into Lγ₅, Lγ₁, Lγ₂₊₃, and Lγ₄ to give the LII and LI subshell ionization cross sections, σ_L₂ and σ_L₁, respectively. The data are compared with simple model calculations. The necessity of including some small but significant additional effects in the plane-wave Born-approximation treatment, particularly wave functions more realistic than the normally assumed hydrogenic forms, is discussed.