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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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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)
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
… 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
The ALADiN Program UNIVERSALITY of Spectator Fragmentation Physics Motivation
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
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
The ALADiN Spectrometer The ALADiN Recipe
First N/Z Effects on Mass Spectra 124Sn 124La 107Sn Discriminant analysis J. Łukasik et al., arXiv:0707.0598 Gross Features and Isotopic Effects
Searching for N/Z effects in... N/Z of light-mass fragments Charge Partition Isotopic Ratios Neutron Emission Gross Features and Isotopic Effects
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
Properties of Hot Fragments Gross Features and Isotopic Effects
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
N/Z Dependence of the Surface Term centrality B = aV· A - aO · A2/3 - aC · Z2/A1/3 - aS · (A-2Z)2 / A + aP· δ / A1/2 n-rich n-poor A.S. Botvina et al., nucl-th/0606060 Gross Features and Isotopic Effects
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
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
Hot Fragments N. Buyukcizmeci et al, EPJA (2005) Odd-even effects Weak dependence on centrality Gross Features and Isotopic Effects
Comparison with SMM Preliminary Gross Features and Isotopic Effects
extra yield in neutron poor case N/Z on Isotopic Ratios Limiting Temperature
N/Z on Isotopic Temperatures Small Small Small Small small small small small small effects small Limiting Temperature
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
Isoscaling Isoscaling and the Symmetry Energy
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
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
S.Albergo et al. Il Nuovo Cimento A (1985) Discussion (I) Decrease in confirmed Apparent Saturation could depend on T
Discussion (II) A. Le Fèvre et al., PRL 94, 162701 (2005) Isoscaling and the Symmetry Energy
In the grand-canonical approximation: Neutrons ...speculation... Conclusion & Outlook
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
…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
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
Preliminary ...seems to... Conclusion & Outlook
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