Understanding RIB Intensities at EURISOL: Key Knowledge Blocks & Procedure

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

2. 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)

3. 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 3He • ● 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)

4. PRODUCTION CROSS SECTIONS • 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

5. PRODUCTION CROSS SECTIONS Features of spallation reactions Experimental data taken at the FRS at GSI Evaporation residues Fission fragments IMF (intermediate-mass fragments) P. Napolitani J. Taieb, M. Bernas, V. Ricciardi • 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.

6. PRODUCTION CROSS SECTIONS Energy dependence Experimental data taken at the FRS at GSI B. Fernandez T. Enqvist T. Enqvist The region on the chart of the nuclides covered by evaporation residues extends with increasing energy available in the system • Useful to: • Fill gaps in target mass • Enhance the production of IMF

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

8. PRODUCTION CROSS SECTIONS Spallation. Model Calculation (ABRABLA)

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

10. 30.8 cm natPb 660 MeV p Fission residue: Evaporation residue: 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 Experiment: at Dubna, Pohorecki et al, NIMA 2006 Calculations: MCNPX2.5.0 + CINDER'90

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

12. 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: http://isolde.cern.ch

13. 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.

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

15. EFFICIENCIES K.H. Schmidt

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

17. TWO-STEP REACTION: ISOL + IN-FLIGHT J. Benlliure et al GSI experiment S294 (November 2006) What is cold fragmentation 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

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

19. B/~ 3 10-4 ToF ~ 72 ps L ~ 18 m A/A ~ 1.3 10-3 B/~ 3 10-4 ToF ~ 100 ps L ~ 36 m A/A ~ 1 10-3 TWO-STEP REACTION: ISOL + IN-FLIGHT Experimental setup at FRS GSI experiment S294 (November 2006) S0-S2: 238U(950 A MeV) + Be 132Sn Z2 ~ DE S2-S4: 124-132Sn + Be  X

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

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

22. BEAM-INTANSITY DATA-BASE Courtesy of Wojtek Gawlikowicz, Univ. Warsaw http://www-w2k.gsi.de/eurisol-t11 http://www.slcj.uw.edu.pl/~wojtek/eurisol_database.php

23. CONCLUSIONS • 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

24. 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