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Fragment Isospin as a Probe of Heavy-Ion Collisions

Fragment Isospin as a Probe of Heavy-Ion Collisions. Symmetry term of EOS Equilibration “Fractionation” – inhomogeneous distribution of isospin Source composition Energy spectra Dynamics : preequilibrium emission / PLF composition Statistical breakup: composition of fragments

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Fragment Isospin as a Probe of Heavy-Ion Collisions

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  1. Fragment Isospin as a Probe of Heavy-Ion Collisions • Symmetry term of EOS • Equilibration • “Fractionation” – inhomogeneous distribution of isospin • Source composition • Energy spectra • Dynamics : preequilibrium emission / PLF composition • Statistical breakup: composition of fragments • recent work at TAMU and IU • Peripheral / mid peripheral events: PLF and MR

  2. projectile neutrons target neutrons projectile protons target protons Z N Johnston,1995 B.A. Li, 1996 Martin poster Rami, 2000 Isospin Equilibration

  3. Isotopic composition of fragments as a signature of parent system R. Wada, Phys. Rev. Lett. 58, 1829-1832 (1987)

  4. Ni+Ni Ni+Fe Fe+Ni Fe+Fe 30MeV/nucleon 58Fe,58Ni + 58Fe, 58NiCarbon fragments Ramakrishnan et al, PRC 57, 1803 (1998)

  5. 58Fe, 58Ni + 58Fe, 58Ni 30 MeV/nucleon Ramakrishnan et al, PRC 57, 1803 (1998) 124,136Xe + 112,124Sn 55MeV/nucleon Dempsey et al, PRC 54, 1710(1996) Martin, et al PRC (2000)

  6. Projectile fragmentation (with isotopically reconstructed QP) • Isospin effects the dynamics • QP with a diversity in isospin • Possible route to neutron-rich RNB • > G.Souliotis clip

  7. Keksis poster 28Si + 112Sn, 124Sn @ 30,50MeV/nucleon 20F,20Ne, 20Na + Au @ 32 MeV/nucleon FAUST

  8. Rowland PLF 20F,20Ne, 20Na + Au @ 32 MeV/nucleon Neutron richness D. Rowland

  9. 20F 20Ne 20Na Projectile fragmentation of 20Na,20Ne,20F at 35 Mev/nucleon Distillation of a neutron-rich gas?

  10. 124Sn 124Sn Veselsky, Phys. Rev. C62, 064613 (2000).

  11. 50 Mev/nucl (N/Z)IMF/(N/Z)LCP (N/Z)QP 28Si + 112Sn; 30 & 50 Mev/nuc projectile fragmentation reactions Both the multiplicity and neutron content of the fragmentation products are dependent on the N/Z of the fragmenting system Veselsky, Phys. Rev. C62, 041605 (2000)

  12. 50 Mev/nuc PLF : Z=12-15 => second source Laforest, PRC 59, 2567 (1999)

  13. Souliotis Clip Rare Isotope Production with MARS Dispersive Image D2 D1 Production Target Wien Filter Q3 Q2 Q1 Final Achromatic Image D3 PPAC1 Start T X,Y Q4 Q5 Rotatable Arm Reaction Angle: 0-12o (selectable) PPAC2 Stop T Silicon Telescope: ΔE1, X,Y (Strips) ΔE2, Er MARS Acceptances: Anglular: 9 msr Momentum: 4 %

  14. Fragments at mid rapidity

  15. Shetty poster larger fragments from midrapidity(Rapidity Dist. for Z = 2, 3, 4 for different Multiplicity Bins) 28MeV/A 209Bi + 136Xe <b> = 12.4 fm 124Xe, 124Sn + 112,124Sn Toke, PRL 75, 2920 ( 1995)

  16. Shetty poster Rapidity Dist. for 3He,4He,6He for different Multiplicity Bins 124Xe, 124Sn + 112,124Sn

  17. 3He, 4He, 6He Spectra Comparison 124Xe, 124Sn + 112,124Sn Elab/A

  18. 114,106 Cd + 92,98 Mo at E/A = 50 MeV LASSA LASSA: 9 telescope Si(IP)-Si(IP)-CsI(Tl)/PD array; 7lab58 Si-CsI(Tl)/PD;2.5lab4.5 Beam Miniball/Wall; Fast plastic/CsI(Tl);2lab170

  19. Reproducing Ramakrishnan(neutron deficient isotopes dominate at central angles) Hudan Clip

  20. Hudan Clip Perpendicular velocity spectra

  21. Fractional yield as function of perpendicular velocity Hudan Clip

  22. Shetty poster Spectral Comparison for Z = 3 Isotopes(change in slope trend for heaviest isotope?) 124Xe, 124Sn + 112,124Sn Elab/A

  23.  isotopic energy spectra (preequilibrium effects) J. Brzychczyk, Phys. Rev. C 47, 1553-1562 (1993) E. Renshaw, Phys. Rev. C 44, 2618-2624 (1991)

  24. Energy Spectra As a Probe Of Symmetry Potential B.A. Li, PRL 78, 1544 (1997)

  25. Isotope ratios as function of centrality 124,136Xe + 112,124Sn 55MeV/nucleon Dempsey et al, PRC 54, 1710(1996) 114Cd + 98Mo; 50MeV/nuc H. Xu Phys. Rev. C 65, 061602 (2002)

  26. Enhanced neutron richness in central versus peripheral collisions H. Xu Phys. Rev. C 65, 061602 (2002)

  27. In the spirit of the Gordon Conf… R 20F,20Ne, 20Na + Au 32 MeV/nucleon

  28. Summary • Fragment Isospin can tell us about • Equilibration • Source composition – distribution of isospin • DIT mechanism can be used to create systems with a diversity of isospin • Isotopic energy spectra are important to understanding the sources of these fragments

  29. The following people were responsible for bringing you the unpublished data shown in this presentation…* • B. Davin, R. Alfaro, H. Xu, L. Beaulieu, Y. Larochelle, T. Lefort, R. Yanez, S. Hudan, A. L. Caraley, R. T. de Souza, T. X. Liu, X. D. Liu, W. G. Lynch, R. Shomin, W. P. Tan, M. B. Tsang, A. Vander Molen, A. Wagner,i H. F. Xi, C. K. Gelbke, R. J. Charity, L. G. Sobotka, A.S. Botvina, D. Rowland, D. Shetty, M. Veselsky, G. Souliotis, E. Martin, A. Keksis, E. Winchester,A. Ruangma G. Charbarian, L. Trache, K. Hagel, T. Keutgen, M. Murray, J.B. Natowitz, L. Qin, R. Wada, M. Cinausero, D. Fabris, E. Fioretto, M. Lunardon, G. Nebbia, G. Prete, V. Rizzi, G. Viesti, J. Cibor, Z. Majka, R. Alfarro, A. Martinez-Davalos, A. Menchaca-Rocha • DOE, NSF, Welch Foundation *However they should not be held accountable for the actual presentation

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