Production and decay of K-shell hollow krypton in collisions with 52–197-MeV/u bare xenon ions
AbstractX-ray spectra of K-shell hollow krypton atoms produced in single collisions with 52–197-MeV/u Xe54+ ions are measured in a heavy-ion storage ring equipped with an internal gas-jet target. Energy shifts of the Kα1,2s, Kα1,2h,s, and Kβ1,3s transitions are obtained. Thus the average number of the spectator L vacancies presented during the x-ray emission is deduced. From the relative intensities of the Kα1,2s and Kα1,2h,s transitions, the ratio of K-shell hollow krypton to singly K-shell ionized atoms is determined to be 14%–24%. In the considered collisions, the K vacancies are mainly created by the direct ionization which cannot be calculated within the perturbation descriptions. The experimental results are compared with a relativistic coupled-channel calculation performed within the independent particle approximation.