1679 Design of the Radioactive Ion Beam Facility at the LNS E. Migneco, R. Alba, L. Calabretta, G. Ciavola, G. Cuttone M. Di Giacomo, S. Gammino, P. Gmaj, M.H. Moscatello G. Raia, D. Rifuggiato, A. Rovelli, J. Sura, Q. Zhou I.N.F.N.-Laboratorio Nazionale de1 Sud - V.le A. Doria ang. via S.Sofia I-95125 Catania Abstract At the “Laboratorio Nasionale de1 Sud” the existing 15 MV Tandem will be coupled to the Superconducting Cy- clotron booster, which will provide light and heavy ion beams in the energy range 100-20 MeV/n. Using these beams, secondary radioactive beams can be produced by projectile fragmentation. A fragment separator will collect the secondary beam produced at energies near that of the projectile and deliver it into the experimental areas. It is also discussed the possibility of using an ECRIS source for the axial injection into the Cyclotron and producing ra- dioactive ions on a thick source placed inside the Tandem preinjector. 1 INTRODUCTION At the “Laboratorio Nationale de1 Sud” (L.N.S.) a 15 MV MP-Tandem has been delivering ion beams since 1983 [l]. In 1993 The Tandem will be coupled to the K-800 Su- perconducting Cyclotron (C.S.) 121, which will permit to reach energies up to 100 MeV/n for fully stripped light ions and up to 20 MeV/n for the heaviest ions, like Bi or U. The project to build a superconducting ECRIS source [3] for axial injection in the C.S. has started and will be completed by 1995. The Cyclotron will work in “stand alone” mode; the beam intensities are expected to be 2- 5 times higher for light ions with respect to the Tandem injection. In addition to the superconducting source, a room temperature one will also be installed. Two differ- ent facilities for the production of secondary beams can be available at L.N.S. in the coming years: a fragment aepa- rator, which has already been designed, and a low energy radioactive beam facility, which is now propoeed. In the first case, radioactive ion beams at intermediate energies (up to 90 MeV/n) can be obtained by projectile fragmen- tation on a thin target, then they will be analyzed and collected by the extraction beam line, which ia designed aa a Fragment Recoil Separator (F.R.S.), and sent directly to the experimental rooms. In the second case, operating the Superconducting Cyclotron in “stand alone” mode by using the external ECR source, the light ions beams will be accelerated at an energy between 50f80 MeV/n and will be transported to the Tandem injector’s area. In the following the main features of the low energy fa- cility and of the F.R.S. will be presented. 2 THE EXCYT (EXOTICS AT THE CYCLOTRON-TANDEM) FACILITY The energetic light ions (50-100 MeV/n) are an alterna- tive to high energy protona (1 GeV) for the production of radioactive nuclei by interaction in a thick target. This so- lution allows to optimise the choice of the projectile-target in order to enhance the production of a given isotope and makes the extraction of secondary beams easier, the target being thinner than in the case of a proton beam. In fig. 1 the layout of the proposed facility is shown. A major feature of this project is that a large part of compo- nents already exist. The new hardware and the modifica- tions of the existing components are shortly described. 2.1 The ECR source A 14.5 GHa superconducting magnets ECR source [3] will be coupled with the C.S. by Autumn of 1995. Moreover a room temperature ECR source will soon be purchased to be dedicated to the production of high intensity light ions beam. In both cases currents up to 1-2 ppA of fully stripped light ione and currents up to 10 ppA of (Z-l)- charged ions will be delivered. Special care haa to be put on the extraction design, because the high magnetic field on the extraction side is detrimental to the emittance, and the performances of the cyclotron inflector are strictly re- lated to the emittance of the beam coming from the source. 2.2 The axial beam line and the inflector The axial injection will be achieved by a couple of solenoids, whoee function ie to reduce the effects of the magnetic field on emittance increase, and by a spiral in- flector. The spiral inflector is the best suited for a Super- conducting Cyclotron, considering the small clearance of the central region (height of the inflector N 2 cm., width - 1.4 cm.) and the fact that the beam can be injected along the axis of the machine (this feature being primor- dial to the quality of the beam). The emittance of the beam and the conditions at the entrance of the inflector determine the inflector’s transmission. As far aa the cen- tral region is concerned, a harmonic 2 operation in cur- rently planned and the design haa been made for a costant orbit mode.