Characterization of Charge States of Energetic Ions in Solids from AssociatedKX-Ray Production

The strong projectile---charge-state dependence of K x-ray production in gases establishes a charge-state scale for ions penetrating solids. Si K x-ray cross sections in gaseous SiH₄ were compared to those in solid Si for 40-MeV O (6+ to 8+) and 86-MeV Ar (6+ to 16+) projectiles. For Ar an effective charge of 11 ±{} 1 is found compared to an emergent charge of 14.8 ±{} 0.5. The result is discussed in terms of alternate models for steady-state excitation in solids.