Relative L-subshell ionisation cross sections for 0.15 to 10 MeV proton bombardment of Dy and Au

The L X-ray spectra of Dy and Au produced by proton impact have been measured over a broad range of projectile energies. From the intensities of characteristic lines the relative ionisation cross sections sigma i of the three L subshells L i were derived. The cross section ratios sigma 1 / sigma 2 and sigma 1 / sigma 3 vary significantly with projectile energy, attaining a maximum at low energies. This behaviour cannot be quantitatively described by available theoretical models.