Fragment properties of fragmenting heavy nuclei produced in central and semi-peripheral collisions.

Eric Bonnet (1, 2) , Bernard Borderie (1) , N. Le Neindre (1, 3) , Marie-France Rivet (1) , R. Bougault (3) , A. Chbihi (2) , R. Dayras (4) , J.D. Frankland (2) , E. Galichet (1, 5) , F. Gagnon-Moisan (1) , D. Guinet (6) , P. Lautesse (6) , J. Lukasik (7) , D. Mercier (3) , M. Pârlog (3) , E. Rosato (8) , R. Roy (9) , C. Sfienti (10) , M. Vigilante (8) , J.P. Wieleczko (2) , B. Zwieglinski (2)

1 IPNO - Institut de Physique Nucléaire d'Orsay
2 GANIL - Grand Accélérateur National d'Ions Lourds
3 LPCC - Laboratoire de physique corpusculaire de Caen
4 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
5 CNAM - Conservatoire National des Arts et Métiers [CNAM]
6 IPNL - Institut de Physique Nucléaire de Lyon
7 IFJ-PAN - Institute of Nuclear Physics
8 Dipartimento di Scienze Fisiche e Sezione INFN
9 Laboratoire de Physique Nucléaire
10 GSI - Helmholtz zentrum für Schwerionenforschung GmbH

Fragment properties of hot fragmenting sources of similar sizes produced in central and semi-peripheral collisions are compared in the excitation energy range 5-10 AMeV. For semi-peripheral collisions a method for selecting compact quasi-projectiles sources in velocity space similar to those of fused systems (central collisions) is proposed. The two major results are related to collective energy. The weak radial collective energy observed for quasi-projectile sources is shown to originate from thermal pressure only. The larger fragment multiplicity observed for fused systems and their more symmetric fragmentation are related to the extra radial collective energy due to expansion following a compression phase during central collisions. A first attempt to locate where the different sources break in the phase diagram is proposed.

Keywords: multifragmentation; central and semi-peripheral collisions; Intermediate energy heavy-ion reactions; fragment partitions; collective energy

Domains: Nuclear Experiment [nucl-ex]

Eric Bonnet, Bernard Borderie, N. Le Neindre, Marie-France Rivet, R. Bougault, et al.. Fragment properties of fragmenting heavy nuclei produced in central and semi-peripheral collisions.. Nuclear Physics A, 2009, 816 (1-4), pp.1-18. ⟨10.1016/j.nuclphysa.2008.11.005⟩. ⟨hal-00335974⟩