Berlin 2005 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 11: Physik mit schweren Ionen

HK 11.6: Vortrag

Freitag, 4. März 2005, 18:30–18:45, TU MA042

Isotopically resolved residues from the fragmentation of projectiles with largely different N/Z — •Daniela Henzlova — GSI Darmstadt, Planckstrasse 1, 642 91, Germany — on leave from Nuclear Physics Institute, 25068 Rez, Czech Republic

With the use of the high-resolution magnetic spectrometer, the FRagment Separator (FRS), at GSI Darmstadt, the isotopic identification of the final residues may be extended up to the mass of the heavy projectile. The dependence of the isotopic composition of final residues on the N/Z of the projectile is studied over the full range of residue charge for 136Xe (N/Z=1.519) and 124Xe (N/Z=1.296) projectiles, fragmenting in a lead target at 1 A GeV. The final mean N-over-Z of the final residues as well as the ratio of isotopic yields from both reactions is investigated. The final mean N-over-Z preserves a memory on the N/Z of the projectile for all charges, a feature which may be related to the break-up of the highly excited primary fragment. The sensitivity of the data to the thermal conditions at the freeze-out after break-up is explored and the isospin-thermometer method is applied to deduce the corresponding freeze-out temperature. The ratios of the isotopic yields from the two reactions exhibit exponential dependence on N and Z, the observation termed isoscaling. The corresponding logarithmic slope is used to extract the symmetry-term coefficient.