BEAM INTENSITIES WITH EURISOL M. Valentina Ricciardi GSI, Darmstadt, Germany

LAYOUT "Blocks of knowledge" to be put together to estimate RIB intensities: 1) Set-up 2) Production cross-sections 3) Production rates 4) Efficiencies 5) Possible combination of ISOL + IN-FLIGHT methods These "blocks of knowledge" are not uncorrelated. How to proceed? 1. We go through each block and see what we know 2. Provide this information to the user in a simple, accessible way (www)

SET-UP Primary beam Standard option: 1 GeV protons: ● on direct target (100 kW) ● on converter target (4-5 MW) Additional possibilities (compatible with the baseline driver accelerator): ● 2 GeV 3 He ● 250 MeV deuterons ● heavier ions with A/Q = 2 up to 125 MeV/u Target Direct target  Protons interact directly with the target material Indirect target  Spallation neutron source (most of the heat load)  Production target (few-MeV neutrons)

Which nuclear reactions are of interest assuming the above set-up? Direct-target option Spallation-evaporation with ≤ 1 GeV protons Spallation-fission with ≤ 1 GeV protons Fission with secondary neutrons Indirect-target option Fission with few-MeV neutrons PRODUCTION CROSS SECTIONS

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 PRODUCTION CROSS SECTIONS P. Napolitani J. Taieb, M. Bernas, V. Ricciardi

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 Energy dependence Useful to: Fill gaps in target mass Enhance the production of IMF PRODUCTION CROSS SECTIONS B. Fernandez T. Enqvist

Fission. Model Calculation (ABLA) PRODUCTION CROSS SECTIONS K. H. Schmidt, A. Kelić

PRODUCTION CROSS SECTIONS Spallation. Model Calculation (ABRABLA)

IN-TARGET PRODUCTION (production rates) Additional things enter into the game: a. Target thickness, material b. secondary projectiles (mostly neutrons) c. decay pattern Important: target material should be feasible! U. Köster

IN-TARGET PRODUCTION (production rates) Residue production in thick-spallation targets (D. Ridikas) J.-C. David et al, Internal report DAPNIA-07-59, June 2007 Fission residue:Evaporation residue: Experiment: at Dubna, Pohorecki et al, NIMA 2006 Calculations: MCNPX CINDER' MeV p 30.8 cm nat Pb

Optimization of in-target yields: Direct targets Optimum target: PbOptimum energy: 1 GeV Optimum target length: ~18 cm? (extraction efficiency) Case 183 Hg Courtesy of S. Chabod IN-TARGET PRODUCTION (production rates)

EFFICIENCIES Specific and precise information on the efficiency, nucleus by nucleus (CERN/ISOLDE) On progress In the meantime, profiting of the valuable database (*) of yields at ISOLDE, a work of Lukić gives an Overview on the overall extraction efficiency (GSI) (*) H.-J. Kluge, Isolde users guide, CERN, Geneva, 1986, web:

EFFICIENCIES Correlation of ISOL yields with isotope half-life  Comparison of ISOLDE- SC yields to in-target production rates  Ratio yield/produced → overall extraction efficiency for the nuclide S. Lukić et al.

EFFICIENCIES Same general behavior found in many cases. S. Lukić et al.

EFFICIENCIES K.H. Schmidt

EFFICIENCIES Can we extract some general tendency from the measured data?...work in progress K.H. Schmidt

J. Benlliure et al GSI experiment S294 (November 2006) Participating institutes: Universidad de Santiago de Compostela, Spain Centre d’Etudes Nucleaires Bordeaux- Gradignan, France Warsow University, Poland GSI Darmstadt, Germany VINCA-Institute Belgrade, Serbia Institute of Physics, Bratislava, Slovakia TWO-STEP REACTION: ISOL + IN-FLIGHT What is cold fragmentation

Two-step schemes: fission + cold fragmentation Production of medium-mass neutron-rich nuclei 1. Produce 132 Sn via fission in uranium target 2. Use cold fragmentation of 132 Sn to produce medium-A neutron-rich nuclei TWO-STEP REACTION: ISOL + IN-FLIGHT

Experimental setup at FRS GSI experiment S294 (November 2006) S0-S2: 238 U(950 A MeV) + Be  132 Sn S2-S4: Sn + Be  X  A/A ~  B  /  ~  ToF ~ 100 ps L ~ 36 m  B  /  ~  ToF ~ 72 ps L ~ 18 m  A/A ~ Z 2 ~  E TWO-STEP REACTION: ISOL + IN-FLIGHT

Fragmentation of 132 Sn (Preliminary results) Fragmentation of 132 Sn on Be D. Perez and D. Dragosavac TWO-STEP REACTION: ISOL + IN-FLIGHT Preliminary cross sections are available

Energy of the post accelerator Charge state can cause impurity TWO-STEP REACTION: ISOL + IN-FLIGHT

BEAM-INTANSITY DATA-BASE Courtesy of Wojtek Gawlikowicz, Univ. Warsaw

Consistent description of nuclide production Calculations of in-target yields in progress Study of the extraction efficiencies in progress Feasibility of the two-step reaction scheme experimentally proven EURISOL beam-intensities data-base in progress CONCLUSIONS

Beam intensities with EURISOL EURISOL DS Task 11 Task leader: Karl-Heinz Schmidt, GSI-Darmstadt Participants and contributors: ISOLDE-CERN, CEA/Saclay, University of Jyväskylä, University of Warsaw, IoP Bratislava, GSI-Darmstadt, University Santiago de Compostella, Khlopin Radium Institute, VINČA-INS Belgrade