Target Z dependence of Xe L x-ray emission in heavy ion-atom collision near the Bohr velocity: Influence of level matching

X-ray yields for the projectile L-shell have been measured for collisions between Xe²⁰⁺ and thick solid targets throughout the periodic table with incident energies near the Bohr velocity. The yields show a very pronounced cyclic dependence on the target atomic number. This result indicates that Xe L x-ray emission intensity is greatly enhanced either in near-symmetric collisions or if the binding energy of the Xe M-shell matches the L- or N-shell binding energy of the target.