Dynamic Screening of Projectile Charges in Solids Measured by Target X-Ray Emission

Abstract

We report a strong dependence of the Al $K$ x-ray cross section in solid Al targets, for thicknesses ranging from 0.5 to 25 \ensuremath{\mu}g/${\mathrm{cm}}^{2}$, on the charge state of the incident oxygen projectiles, in the energy range 12-68 MeV. The results are analyzed in terms of the dynamic screening of the projectile charge by the electrons in the dense target, yielding a dynamic screening rate $\ensuremath{\lambda}=5.5\ifmmode\times\else\texttimes\fi{}{10}^{14}$ ${\mathrm{sec}}^{\ensuremath{-}1}$ which is consistent with this approach.