Double K-shell vacancies produced in near-symmetric collisions with Z∼53

During bombardment of targets (Z=47-57) with 80 MeV iodine beams double K-shell vacancies were detected by observing with solid-state detectors two coincident K X-rays. The indium Kalpha hypersatellite transition was found to be shifted by 500+or-30 eV from the Kalpha satellite line. The sharing of the double vacancies between the target and the projectile ions was observed and found to agree with current models. If the double vacancies are considered as arising from double L-shell vacancies from a previous collision being carried into a second collision and transferred into the K shell, then the shape of the Z2 dependence of the cross section may be reproduced.