摘要
In collisions between energetic heavy ions and atoms,the strong Coulomb field of one of collision partners can cause double K-shell ionization of the second one.In previous work we have studied the mechanism of double K-shell ionization in krypton atom by bare xenon under different perturbation strengths κ=Zp/vp,where Zp is the charge of the projectile and vp is its velocity in atomic units.The measured double-to-single K-shell ionization cross-section ratio is proportional to the perturbation strengthin the rough region of κ<1,but shows less rapidly increasing when κ>1[1].In order to further investigate such process in a wide rang of perturbation strength,an experiment focusing on K-shell ionization of ions was carried out at HIRFL-CSR in 2017.Ni19+ions with a energy of 95 MeV/u were stored in CSRe to interact with hydrogen,argon,krypton and xenon target,respectively.The X rays produced in collisions of the ions with the target were detected by two Silicon Drift Detectors(SDD)mounted at 35◦and 60◦observation angles with respect to the ion beam direction.
