Relationship between charge states and spatial arrangement of constituent ions dissociated from C ion passing through a thin foil

Chiba, Atsuya; Saito, Yuichi; Narumi, Kazumasa; Yamada, Keisuke; Kaneko, Toshiaki*

The average charge states of swift cluster ions passed through a thin foil are smaller than that of the single ions at the same speed. It is considered that such a phenomenon is derived from the mutual screened Coulomb interactions among the cluster constituent ions and the collective excitations of the target electrons induced by the constituent ions. In order to evaluate the contribution to the charge states from the fields of the collective excitations formed at the backward of the moving ion, using the C ions, the charge states measurements were performed taking into account the relative position (leading and trailing) of the constituent ions. The experimental results showed that the charge states of the trailing ions are larger than that of the leading ions, and that this tendency becomes strong with increasing the product of charges.