Cooling Dynamics in Multifragmentation processes.pdfVIP

Cooling Dynamics in Multi-fragmentation processes T.X. Liu, W.G. Lynch, M.J. van Goethem, X.D. Liu, R. Shomin, W.P. Tan, M.B. Tsang, 1 2 3 G. Verde, A. Wagner , H.F. Xi , H.S. Xu , National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA, W. A Friedman, Department of Physics, University of Wisconsin, Madison, WI 53706, USA, S.R. Souza, R. Donangelo, Instituto de Fisica, Universidade Federal do Rio de Janeiro Cidade Universitária, CP 68528, 21945-970 Rio de Janeiro, Brazil L. Beaulieu, B. Davin, Y. Larochelle, T. Lefort, R. T. de Souza, R. Yanez, V. E. Viola, Department of Chemistry and IUCF, Indiana University, Bloomington, IN 47405, USA, R.J. Charity, and L.G. Sobotka, Department of Chemistry, Washington University, St. Louis, MO 63130, USA Abstract Fragment energy spectra of neutron deficient isotopes are significantly more energetic than those of neutron rich isotopes of the same element. This trend is well beyond what can be expected for the bulk multi-fragmentation of an equilibrated system. It can be explained, however, if some of these fragments are emitted earlier through the surface of the system while it is expanding and cooling. 1 Institut für Kern- und Hadronenphysik, Forschungszentrum Rossendorf, D-01314 Dresden, Germany. 2 Present address: Benton Associates, Toronto, Ontario, Canada. 3 Institute of Modern Physics, Lanzhou, China 1 The yields of particles emitted in intermediate energy [1,2], relativistic [3,4]