On the L-M-N multiple ionisation in heavy elements

The L X-ray spectra of Au and Th have been measured in collisions with C, F, Mg, Si, S and Cu ions in the energy range 0.5-2.5 MeV amu -1 . From the shifts of the yield ratios and energies of the L/sub // , L alpha , L eta and L y1 lines relative to those for 2.5 MeV proton bombardment, the average numbers of M 4.5 (and N 4 ) vacancies present during the L-vacancy decay have been determined. The corresponding outer-shell ionisation probabilities show remarkable agreement with the geometrical model of Sulik et al. (1985) except for the Cu projectile.