Etude de la multifragmentation dans les collisions centrales pour le systèmes $^(129)$Xe+$^(nat)$Sn entre 32 et 50 MeV/A : mesure de l'énergie collective d'expansion et du volume de freeze-out

Abstract : The multifragmentation of the nuclear system formed in the central collisions of the Xe+Sn reaction between 32 and 50 MeV/A has been studied with the INDRA detector. A tensorial analyse is used to select central collisions. An important part of the charge (about 85 %) is isotropically emitted. The charge partitions have the caracteristics of a simultaneous multiple fragment emission. The shape of the fragment kinetic energy distributions together with the reduced velocity correlation functions indicate that the fragmentation is a simultaneous process that occures at low density. A comparison between the experimental data and predictions of the statistical multifragmentation model of Copenhagen (SMM) shows that charge partitions agree with the hypothesis of a thermodynamical equilibrium, whereas, kinetic observables are more contraining to the model and difficult to reproduce. However, fragments correlation functions are used in order to extract the freeze-out volume and the collective radial energy. At 50 MeV/A, the freeze-out volume is estimated to be 2.7 times the normal volume. It decreases with incident energy evolves to be nearly twice the normal volume at 32 MeV/A. The collective energy evolves from 0 to 1.3 MeV/A with the bombarding energy. This expansion is not purely thermal and originates probably from a dynamical compression developpe in the early stage of the collision.
Document type :
Theses
Physique Nucléaire Théorique [nucl-th]. Université de Caen, 1997. Français


https://tel.archives-ouvertes.fr/tel-00003688
Contributor : Admin Base Des Publications de L'In2p3 <>
Submitted on : Tuesday, November 4, 2003 - 9:49:21 AM
Last modification on : Friday, September 11, 2015 - 10:02:37 AM
Document(s) archivé(s) le : Wednesday, September 12, 2012 - 11:20:10 AM

Identifiers

  • HAL Id : tel-00003688, version 1

Collections

Citation

Stéphanie Salou. Etude de la multifragmentation dans les collisions centrales pour le systèmes $^(129)$Xe+$^(nat)$Sn entre 32 et 50 MeV/A : mesure de l'énergie collective d'expansion et du volume de freeze-out. Physique Nucléaire Théorique [nucl-th]. Université de Caen, 1997. Français. <tel-00003688>

Export

Share

Metrics

Record views

356

Document downloads

35