L-shell x-ray production cross sections forO16ions on Ce, Pr, Sm, Eu, Dy, and Ho: 0.50 to 2.25 MeV/amu

Abstract

L-shell and individual x-ray production cross sections for 8--36-MeV oxygen ions on thin solid targets of Ce, Pr, Sm, Eu, Dy, and Ho are measured and compared with predictions of theories of direct Coulomb ionization. In comparing theory and experiment, we use, with reasonable justification, fluorescence yields, Coster-Kronig yields, and radiative widths obtained from single-hole initial configurations. The theoretical treatment which provides the best overall fit to the data is the plane-wave Born approximation with corrections for Coulomb deflection of the projectile and increased binding of the target electrons. The effects of multiple ionization are examined through measurement of x-ray energy shifts as measured with Si(Li) detectors and by vacuum crystal- spectrometer measurements of L x-ray spectra produced by 3-MeV proton and 25-MeV oxygen-ion bombardment of a thick La target.