A Charge State Breeder Based on a Low Frequency Rfq for the Isac Accelerator Complex

The new ISAC-II facility has just been funded. The main goals of this extension to the ISAC facility are: expanding the mass range from A ≤ 30 to A ≤ 150 and increasing the final energy from 1.5 MeV/nucleon to 6.5 MeV/nucleon. The accepted mass to charge ratio for the actual 36 MHz RFQ is A/q ≤ 30/1. In order to increase the mass range to 150 we have to increase the charge-state to at least 5+. This can be achieved by three different methods: i) using a charge state breeder based on an EBIS as developed at REX-ISOLDE [1], ii) using an ECRIS or ECRIT based on an ECR as developed at Grenoble [2, 3], iii) using a gas charge-state stripper based on a low frequency RFQ [4]. Since intense RIB are difficult to produce it is of primary importance to obtain the highest overall charge-state breeding efficiency and to preserve the beam quality, small emittance and beam purity. In comparing the three above methods, our analysis shows that the combination of a low frequency RFQ and a gas stripper offers the best overall performance.