Orientation-dependent yields of characteristic X-ray emission from bombardment of Au single crystals by S ions

We have measured the S-K and Au-M X-ray yield for the system 45 MeV Ssup(q+) (q =13-15) on the <111> axis of a thin monocrystalline Au target (500 A). A strongly enhanced (factor 5) S-K X-ray yield is observed for q = 15+ in the channeling direction compared to the random direction and to the yields with lower projectile charge states. The target M X-ray yield depends on the crystal orientation too. The data are interpreted by a model using orientation-dependent cross sections for K vacancy production, decay and electron transfer. (orig.)