SECONDARY-BEAM PRODUCTION: PROTONS VERSUS HEAVY IONS A. Kelić, S. Lukić, M. V. Ricciardi, K.-H. Schmidt GSI, Darmstadt, Germany  Present knowledge on nuclear-reaction mechanisms relevant for RIB production  FAIR radioactive ion beams  EURISOL LAYOUT -General aspects of nuclear reactions relevant for EURISOL -Specific options of the driver accelerator of EURISOL M. Veselsky Institute of Physics, Bratislava, Slovakia

INTRODUCTION Technical solutions based on: - IFF: in-flight separation (FAIR) - ISOL: isotope separation on-line (EURISOL) The working group recommended the construction of two new-generation complementary RIB facilities in Europe, one based on the IFF method and the other on the ISOL method. Roadmap for Construction of Nuclear Physics Research Infrastructures in Europe

PRESENT KNOWLEDGE ON NUCLEAR-REACTION MECHANISMS RELEVANT FOR RIB PRODUCTION 238 U + p at 1 A GeV Experimental data taken at the FRS at GSI Calculation: ABRABLA code (GSI)

RADIOACTIVE ION BEAMS AT FAIR (Facility for Antiproton and Ion Research) "A key feature of the new facility will be the generation of intense, high-quality secondary beams, generated through in-flight fragmentation (super-FRS). Compared to the present GSI facility, up to a factor of 10,000 in secondary radioactive beam intensities is the technical goal." The estimate of the RIB intensity is simplified by the following constrains: target material is fixed (carbon, Z=6) accelerator parameters are fixed the super-FRS characteristics are fixed Fragmentation-fission reactions and fragmentation-evaporation reactions are calculated with different beam type, target-thickness and beam-energy: the best combination for each nuclide is chosen to produced the following figure the reaction mechanism is the main determinant to evaluate RIB intensities

PREDICTION OF RIB PRODUCTION RATES AT FAIR Prediction based on the ABRABLA and EPAX codes, GSI. K.-H. Schmidt, 2001.

Baseline driver beam: 1 GeV proton - 4 MW on a converter-target kW on direct target Which extended capabilities of the driver accelerator would provide substantial benefits in specific cases? (Task 11, subtask 1 of EURISOL Design Study) 5 cases will be presented RADIOACTIVE ION BEAMS AT (Isotope Separation On-Line Radioactive Ion Beam Facility ) "The EURISOL project aims at the ‘next-generation’ European Isotope Separation On- Line (ISOL) Radioactive Ion Beam (RIB) facility. The latter will extend and amplify, beyond the year 2010, the exciting work presently being carried out at the first generation RIB facilities, in Europe and all over the world, in the fields of Nuclear Physics, Nuclear Astrophysics and Fundamental Interactions." Technical constrains are strongly relevant to evaluate RIB intensities

EURISOL General aspects of nuclear reactions Experimental data taken at the FRS at GSI Features of spallation reactions  Spallation-evaporation produces nuclides reaching from the projectile to about 10 to 15 elements below (a few of them are neutron-rich, most of them are neutron-deficient)  Spallation-fission (from Th, U) produces neutron-rich nuclides up to Z=65. IMF (intermediate- mass fragments) Fission fragments Evaporation residues

EURISOL General aspects of nuclear reactions Case 1 Evaporation residues - energy dependence The region on the chart of the nuclides covered by evaporation residues extends with increasing energy available in the system Experimental data taken at the FRS at GSI

Filling gaps in target mass U. Köster, Radiochim. Acta 89 (2001) 749 EURISOL Specific options of the driver accelerator Case 1 Production of neodymium (Z=60) isotopes with  Z targ = 2, 12, 22 Calculation with ABRABLA Production at 1 GeV with  Z targ = 12 is comparable with 2 GeV with  Z targ = 22 Z targ = 62 Z targ = 72 Z targ = 82  2 GeV 3 He beam

EURISOL General aspects of nuclear reactions Case 2 IMF - energy dependence Steep increase of IMF production with increasing beam energy Experimental data taken at ISOLDE, CERN. Calculations performed with ABRABLA, GSI Production of sodium (Z=11) in 238 U+p at several energies

Enhanced production of IMF EURISOL Specific options of the driver accelerator Case 2 Production of neutron-rich IMF from 238 U enhanced by higher beam energy Calculation with INCL/ABRABLA  2 GeV 3 He beam

EURISOL General aspects of nuclear reactions Case 3 Calculation performed with the ABRABLA code, GSI Fission fragments - energy dependence  Nuclide production on two limited neutron-rich regions of the chart of the nuclides

Deuteron beam EURISOL Specific options of the driver accelerator Case 3 Deuteron option provides enhanced production for symmetric and very asymmetric fission Calculations with ABRABLA d, E conv erter n, ½ E p, 1 GeV conv erter n, 2 MeV Deuteron converter versus high-power proton converter

EURISOL General aspects of nuclear reactions Case 4 Deep-inelastic transfer products (DIT) (similar to fission): ● Exp. data taken at Texas A&M □ DIT+Gemini calculation Heavy-ions reactions at Fermi energy 124 Sn+ 124 Sn at 20 A MeV - G.A. Souliotis et al., NIM B 204 (2003) Evaporation residues (EVR): EPAX calculation DIT EVR Z=27Z=26 Z=25Z=24

EURISOL Specific options of the driver accelerator Case 4 Heavy-ions reactions at Fermi energy Benefits for the production of neutron-rich nuclei of light elements

Heavy-ion beam EURISOL Specific options of the driver accelerator Case 5

CONCLUSIONS The knowledge on reaction mechanisms was exploited to investigate the production of RIBs both for a IFF facility (FAIR) and for an ISOL facility (EURISOL). Specifically: 1.Under the fixed technical constrains given at FAIR, the intensities of the future RIBs at FAIR were estimated nuclide by nuclide exploiting the most suited reaction mechanism and target-beam combination 2.On the basis of the 1 GeV proton driver beam planned at EURISOL, different reaction mechanisms were studied to explore which extended capabilities of the driver accelerator would provide substantial benefits in specific cases. The study showed that: A deuteron beam of some tens of MeV (deuteron-converter option) would yield wider nuclide distribution of fission products compared to the 1 GeV proton converter option A 2 GeV 3 He beam would: 1) fill gaps in the masses far below available targets; 2) enhance the production of neutron-rich IMFs (gain factor 3 to 5) Heavy-ion beams would provide: 1) higher production of light neutron-deficient nuclides via fragmentation; 2) higher production of light neutron-rich nuclides via deep-inelastic-transfer reaction