Beam optics design of the REX-ISOLDE q/m-separator

In the radioactive beam experiment (REX) at ISOLDE/CERN radioactive singly charged ions are delivered by the online mass separator ISOLDE and are acce lerated up to 2.2 MeV/u by a new concept, using a linear accelerator consis ting of a RFQ accelerator, an IH-structure and three 7-gap-resonators (Habs et al., Nucl. Instr. and Meth. B 126 (1997) 218). The ions coming from ISO LDE are first accumulated, bunched and cooled in a Penning Ion Trap (REXTRA P), which is similar to ISOLTRAP (Bollen et al., Nucl. Instr, and Meth. A 3 68 (1996) 675). Then, in an electron beam ion source (REXEBIS) charge multi plication takes place. Finally, the highly charged ions are accelerated in the LINAC. As the ions coming out from the EBIS contain impurities coming f rom residual gas inside the EBIS, an accurate q/m selection is necessary be fore the beam is injected into the RFQ accelerator. This paper presents the design of the REX-ISOLDE separator. (C) 1999 Elsevier Science B.V. All rig hts reserved.