MODIFICATIONS TO BASE-LINE ISL DESIGN DUE TO THE LARGE RANGE OF (Q A)/

The ISL baseline post-accelerator design as described in the ISL conce pt document(1) cannot match the velocity profile of RFQ1 and RFQ2 over the full charge to mass ratios required without some modification. Th e minimum modification needed is to add an rf accelerating module betw een RFQ1 and RFQ2. At this workshop for the purpose of minimizing the longitudinal phase space growth, a prebuncher/chopper system was added in front of RFQ1. This allows the added rf acceleration module to be placed in front of RFQ1, allowing RFQ1 to be at ground potential. This is a nice solution if the buncher/chopper system can handle the width range of energy per nucleon. This solution provides for a constant ve locity profile past the rf acceleration module for all species of ions .