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Concettina Sfienti, GSI Darmstadt

Isotopic Effects in Spectator Fragmentation at Relativistic Energies. Concettina Sfienti, GSI Darmstadt. Physics Motivation. The ALADiN Recipe. Gross Features and Isotopic Effects. Limiting Temperature. Isoscaling and the Symmetry Energy. Conclusion & Outlook. NUFRA2007

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Concettina Sfienti, GSI Darmstadt

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  1. Isotopic Effects in Spectator Fragmentation at Relativistic Energies Concettina Sfienti, GSI Darmstadt Physics Motivation The ALADiN Recipe Gross Features and Isotopic Effects Limiting Temperature Isoscaling and the Symmetry Energy Conclusion & Outlook NUFRA2007 International Conference on Nuclear FragmentationFrom Basic Research to Applications September 24 - October 1, 2007, Kemer (Antalya)

  2. The 2000 Collaboration S.Bianchin, K.Kezzar, A.Le Fèvre, J.Lühning J.Lukasik, U.Lynen, W.F.J. Müller, H.Orth, A.N.Otte, H.Sann, C.Sfienti, C.Schwarz, A.Sokolov, W.Trautmann, J. Wiechula, M.Hellström, D.Henzlova, K.Sümmerer, H.Weick, P.Adrich, T.Aumann, H.Emling, Y.Leifels, R.Palit, H.Simon, H.Johansson, M.De Napoli, G.Imme', G.Raciti, E.Rapisarda, R.Bassini, C.Boiano,I.Iori, A.Pullia,W.G.Lynch, M.Mocko, M.B.Tsang, M.Wallace, C.O.Bacri, A.Boudard, J-E.Ducret, A. Lafriakh, E.Le Gentil, C.Volant, T. Barczyk, J.Brzychczyk, J.Cibor, Z.Majka, A.Mykulyak, P.Pawlowski, A.Wieloch, B. Zwieglinski, B.Czech and A.S.Botvina

  3. … study nuclear matter under extreme conditions of density (high and low), temperature, size , isospin… • Disadvantages: • Typical Incident Energy  30AMeV • Flow • scentralcollision  0 • Overlap Participant & Spectators • Spectators can be heated ! • Advantages of the Recipe • Typical Incident Energy  1 AGeV • (almost) no flow • Source well localized in rapidity • Equilibrated System • Easy 4p coverage for fragments • Disadvantages of the Recipe • Varying Size of the system by varying Excitation Energy. Physics Motivation

  4. The ALADiN Program UNIVERSALITY of Spectator Fragmentation Physics Motivation

  5. The ALADiN Caloric Curve J. Besprosvany and S. Levit Phys. Lett B 217 (1989) 1 J.B. Natowitz et al., Phys.Rev. C 65 034618 (2002) Proton rich nuclei: vanishing limiting temperatures Physics Motivation

  6. ALADiN Magnet TP-MUSIC III HodoCT Target TOF-Wall LAND The ALADiN Spectrometer • ALL Fragments (Z 2) • Isotope Resolution • Protons...(but TOF) Neutrons! Secondary Beams (Low Intensities!) 124Sn,197Au,124La,107Sn Einc = 600AMeV ( 1000 p/sec) The ALADiN Recipe

  7. The ALADiN Spectrometer The ALADiN Recipe

  8. First N/Z Effects on Mass Spectra 124Sn 124La 107Sn Discriminant analysis J. Łukasik et al., arXiv:0707.0598 Gross Features and Isotopic Effects

  9. Searching for N/Z effects in... N/Z of light-mass fragments Charge Partition Isotopic Ratios Neutron Emission Gross Features and Isotopic Effects

  10. N/Z Effects on Charge Partition At low excitation energy neutron emission of heavy residue suppressed for the neutron-poor systems Gross Features and Isotopic Effects

  11. Properties of Hot Fragments Gross Features and Isotopic Effects

  12. Isotopic Inversion of t Properties of Hot Fragments: the Surface term B0 = 18 MeV R. Ogul and A.S. Botvina, PRC (2002) Gross Features and Isotopic Effects

  13. N/Z Dependence of the Surface Term centrality B = aV· A - aO · A2/3 - aC · Z2/A1/3 - aS · (A-2Z)2 / A + aP· δ / A1/2 n-rich n-poor A.S. Botvina et al., nucl-th/0606060 Gross Features and Isotopic Effects

  14. N/Z Effects on Neutrons Multiplicities (N/Z) projectile  neutron initial (by P.Pawlowski) ●●● SMM ensemble calculations for γ=14, preliminary Gross Features and Isotopic Effects

  15. 238U 238U 124Sn 56Fe 107Sn 56Fe Light Fragments (inclusive) close to expectation for hot fragments FRS data 124Sn 107Sn Z=8 FRS data W.Trautmann, NN2006 Odd-Even Effects  Structure effects Memory Effects  They may cancel in scaling plots Odd-Even Effects larger for the proton-rich systems  Strongly bound even-even nuclei attract a large fraction of the product yield in the secondary stage Gross Features and Isotopic Effects

  16. Hot Fragments N. Buyukcizmeci et al, EPJA (2005) Odd-even effects Weak dependence on centrality Gross Features and Isotopic Effects

  17. Comparison with SMM Preliminary Gross Features and Isotopic Effects

  18. extra  yield in neutron poor case N/Z on Isotopic Ratios Limiting Temperature

  19. N/Z on Isotopic Temperatures Small Small Small Small small small small small small effects small Limiting Temperature

  20. M.B. Tsang et al., PRC 64, 054615 (2001) M.B.Tsang et al. PRL123(2001) Isoscaling «systematic behavior of yield ratios following grandcanonical expectations» Isoscaling and the Symmetry Energy

  21. Isoscaling Isoscaling and the Symmetry Energy

  22. p0 fit of individual Z fits …from isoscaling to g Increase in temperature does not compensate decrease of First experimental conclusion: The individual slopes are identical for Z≥3 Second experimental conclusion: The Isoscaling parameters continue to drop Isoscaling and the Symmetry Energy

  23. A. Le Fevre et al., PRL 94(2005) 162701 D.V. Shetty et al., PRC 76(2007) 024606 Comparison with existing data…. Isoscaling and the Symmetry Energy

  24. S.Albergo et al. Il Nuovo Cimento A (1985) Discussion (I) Decrease in confirmed Apparent Saturation could depend on T

  25. Discussion (II) A. Le Fèvre et al., PRL 94, 162701 (2005) Isoscaling and the Symmetry Energy

  26. In the grand-canonical approximation: Neutrons ...speculation... Conclusion & Outlook

  27. What have we learnt? Isotopic Effects • Global N/Z effects are small • Isotope distributions exhibit memory and structure effects • Temperature invariant with N/Z in contradiction to limiting temperature assumption • Isoscaling • Isoscaling data extended into the vaporization regime • Reduced symmetry term at freeze-out • …something…. Conclusion & Outlook

  28. …need to be answered… • Why does the limiting temperature approximation seem to work so well for the masses but not for the isospin? • Isoscaling...why does it work so well? • Does D really remain constant? • Unique Chance: NEUTRONS! Conclusion & Outlook

  29. The 2000 Collaboration S.Bianchin, K.Kezzar, A.Le Fèvre, J.Lühning J.Lukasik, U.Lynen, W.F.J. Müller, H.Orth, A.N.Otte, H.Sann, C.Sfienti, C.Schwarz, A.Sokolov, W.Trautmann, J. Wiechula, M.Hellström, D.Henzlova, K.Sümmerer, H.Weick, P.Adrich, T.Aumann, H.Emling, Y.Leifels, R.Palit, H.Simon, H.Johansson, M.De Napoli, G.Imme', G.Raciti, E.Rapisarda, R.Bassini, C.Boiano,I.Iori, A.Pullia,W.G.Lynch, M.Mocko, M.B.Tsang, M.Wallace, C.O.Bacri, A.Boudard, J-E.Ducret, A. Lafriakh, E.Le Gentil, C.Volant, T. Barczyk, J.Brzychczyk, J.Cibor, Z.Majka, A.Mykulyak, P.Pawlowski, A.Wieloch, B. Zwieglinski, B.Czech and A.S.Botvina Conclusion & Outlook

  30. Preliminary ...seems to... Conclusion & Outlook

  31. Anode & Pad Readout • 12 mm pad modulo-five connected Reduces the number of readout ch. from 80 to 17  Fine position determination from PAD readout Rough positionfrom charge-division method of the anode wires  Resolve the position ambiguity. PreAmp Anode wires Resistive charge division readout Pad readout in groups The ALADiN Recipe

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