Projectile dependence of single-Kmultiple-Lshell vacancy production in argon: A universal scaling of〈l〉

Argon $K\alpha$ x-ray satellites produced by ion collisions have been analyzed in high resolution. Ions of H, C, N, O, F, Si, and Cl with energies in the range 1-5 MeV/amu were used to bombard argon contained in a gas cell. This study is the first systematic study of $K$ x-ray satellites from free-atom targets with $Z>\mathrm{}10\mathrm{}$. The relative satellite intensities and satellite energies are tabulated and their projectile dependence is qualitatively discussed. The average number of $L$-shell vacancies formed in single-$K$-vacancy-producing collisions is determined from a model calculation based on theoretical decay rates. This model includes (i) the variation in fluorescence yield, and (ii) the variation in $L$-shell rearrangement with the number of $L$-shell and $M$-shell electrons. The averages obtained from the model calculation are nearly the same as the $〈l〉$ values obtained by weighting the x-ray satellites equally. A universal scaling of $〈l〉$ in $Z_1$ and projectile velocity is obtained on the basis of an increased binding effect. This is the first successful demonstration of a scaling law for multiple ionization by heavy ions.