Accel-Decel Method of Producing High-Q Low Velocity Ions

The double EN tandem Van de Graaff accelerators at the University of Pittsburgh's Nuclear Physics Laboratory have been used in part since 1978, operating in the 3-stage mode, as a source of highly stripped but low velocity ions for experiments of interest to atomic physics. Much of the work has involved investigating the technical details of this new accel-decel technique and gaining practical experience in operating the accelerators in the acceldecel mode. Decelerations to a final energy a factor of ≈ 50 less than the stripping energy have been achieved for fully stripped oxygen ions, and some charge exchange measurements on He published, demonstrating the potential of the accel-decel technique for supplying atomic physics with data from a previously unattainable energy and charge state regime. Practical problems encountered and the technical developments leading to these first prototype experiments will be reviewed. Subsequent developmental work, the present status of the project, and future technical plans at Pittsburgh are summarized. Finally, the future possibilities of the accel-decel technique generally are discussed.