THE SPES PROJECT: RESEARCH AND DEVELOPMENT FOR THE MULTI-FOIL DIRECT TARGET M. Manzolaro, A. Andrighetto, L. Biasetto, S. Carturan, M. Libralato, G. Prete, D. Scarpa, LNL-INFN, Viale dell'Università 2, Legnaro, Italy G. Meneghetti, University of Padova, Department of Mechanical Engineering, Via Venezia 1, Padova, Italy P. Colombo, University of Padova, Department of Mechanical Engineering, Via Marzolo 9, Padova, Italy P. Zanonato, University of Padova, Department of Chemistry, Via Marzolo 8, Padova, Italy P. Benetti, University of Pavia, Department of Chemistry and INFN, Via Taramelli 12, Pavia, Italy M. Guerzoni, INFN, Viale Berti Pichat 6/2, Bologna, Italy I. Cristofolini, B. Monelli, University of Trento, Department of Mechanical Engineering, Via Mesiano 77, Trento, Italy. Abstract SPES is a facility to be built at National Institute of Nuclear Physics (INFN-LNL, Legnaro, Italy) intended to provide intense neutron-rich Radioactive Ion Beams (RIBs) [1] directly hitting a UCx target with a proton beam of 40 MeV and 0.2 mA; RIBs will be produced according to the ISOL technique and the new idea that characterize the SPES project is the design of the production target: we propose a target configuration capable to keep the number of fissions high, the power deposition low and the release of the produced isotopes fast. In this work we will present the recent results on the R&D activities regarding the multi-foil direct UCx target. INTRODUCTION The SPES project is focused on the production of neutron-rich radioactive nuclei by ISOL technique, employing the proton induced fission on a direct target of UCx; the fission rate expected with a proton beam of 40 MeV and 0.2 mA is 10 13 fissions/s. The main goal of the SPES facility [1] is to provide an accelerator system to perform forefront research in nuclear physics by studying nuclei far from stability, in particular neutron-rich radioactive nuclei with masses in the range of 80–160. The final RIB energy on the experimental target will be up to 11 MeV for A = 130, with an intensity in the range 10 7 –10 9 pps, depending on the extracted ion species. The bombarding energy achieved allows to overcome the Coulomb barrier in most systems and opens up new possibilities for experimental studies of neutron-rich nuclei, employing different reaction mechanisms such as Coulomb excitation, inelastic scattering, single and multiple nucleon transfer, fusion reactions, etc. In an ISOL facility the working core is constituted by the production target and the ion source [2]: they have to be designed and optimized carefully in order to obtain the desired RIB production rate (see Fig. 1). In the SPES project, the RIBs extracted from the ion source (coupled to the production target by means of the transfer line) will go through a first stage of A/Z purification, which allows to trap the largest amount of radioactive contaminant. Figure 1: The SPES production target and the ion source. A small Wien filter will be placed in the platform just beyond the source; it will be followed by a 1/20000 isobar mass separator. To optimize the reacceleration, a charge breeder will be developed to increase the charge state to N+ before the injection of the exotic beam in the PIAVE Superconducting RFQ, which represents the first re- acceleration stage; the second and final reacceleration step will take place in the ALPI superconducting linear accelerator: as reported above, the final RIBs energy on experiments will be up to 11 MeV. THE TARGET SYSTEM In the production target - ion source complex for ISOL based facilities, many physical phenomena occur: power deposition, fission, atomic diffusion-effusion, ionization, extraction. In the SPES project, the primary proton beam is stopped in the target, dissipating its power and generating by fission exotic nuclei in the intermediate mass range (80< A< 160) [1]. The desired exotic species must be extracted from the target, ionized and accelerated to make a RIB. This process is time demanding and usually unsuitable for atoms having half lives lower than MO-08 Proceedings of HIAT09, Venice, Italy 12 Radioactive Ion Beam Facilities