Multiple ionization state of Ar ^q+ ions during collisions near the Bohr velocity

In order to clarify the mechanism and the influence of the initial charge state and target atomic parameters for the formation of L-shell multiple ionization state of Ar ^q+ ions produced by the collisions near the Bohr velocity, the k-shell x-ray emission of Ar is measured for 1.2 MeV Ar ^{q+(q=4, 6, 8, 9, 11, 12)} ions impacting on V target and 3 MeV Ar ¹¹⁺ ions interacting with selected targets (Z ₂ = 23, 26, 27, 28, 29, 30). It is found that the measured Ar Kα and Kβ x-ray energies shift to the high energy side, and the relative intensity ratios of Kβ/Kα are enlarged than the atomic data, owing to the presence of out-shell multiple vacancies. The multiple ionization is almost independence of the projectile charge state, but is diminished with increasing target atomic number.