Collision experiment on highly ionized ions using vacuum spark source

Cross sections for one-electron capture by Fe6+ in H2 are measured below 10 keV by using a vacuum spark ion source. It is found that the cross sections show little dependence on the collision energy and this value is about 6 x 10-15 cm2. This ion source, which has no electrode for ion extraction, can produce ions from several hundreds eV to several tens of keV and the maximum charge state of 16 in Fe at 125J discharge energy. With ion selection system of 2.7 m time-of-flight and an electrostatic analyzer of 1% resolving power, 102 - 103 ions/pulse are obtained. Because of poor reproducibility of ion beam, charge-transferred ions and unreacted ions are measured simultaneously with a microchannel plate which has two anodes behind. By utilizing the feature of pulsed ion beam and this ion selection system, it is possible to obtain cross sections for various charge states of ions simultaneously. (author)