title: Isospin fractionation in nuclear multifragmentation
abstract: Isotopic distributions for light particles and intermediate mass fragments have been measured for 112Sn+112Sn, 112Sn+124Sn, 124Sn+112Sn, and 124Sn+124Sn collisions at E/A = 50 MeV. Isotope, isotone, and isobar yield ratios are utilized to estimate the isotopic composition of the gas phase at freeze-out. Analyses within the equilibrium limit imply that the gas phase is enriched in neutrons relative to the liquid phase represented by bound nuclei. These observations suggest that neutron diffusion is commensurate with or more rapid than fragment production.
authors.affiliation: National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA.
authors.initials: HS
authors.lastname: Xu
authors.initials: MB
authors.lastname: Tsang
authors.initials: TX
authors.lastname: Liu
authors.initials: XD
authors.lastname: Liu
authors.initials: WG
authors.lastname: Lynch
authors.initials: WP
authors.lastname: Tan
authors.lastname: Vander Molen A
authors.initials: G
authors.lastname: Verde
authors.initials: A
authors.lastname: Wagner
authors.initials: HF
authors.lastname: Xi
authors.initials: CK
authors.lastname: Gelbke
authors.initials: L
authors.lastname: Beaulieu
authors.initials: B
authors.lastname: Davin
authors.initials: Y
authors.lastname: Larochelle
authors.initials: T
authors.lastname: Lefort
authors.lastname: de Souza RT
authors.initials: R
authors.lastname: Yanez
authors.initials: VE
authors.lastname: Viola
authors.initials: RJ
authors.lastname: Charity
authors.initials: LG
authors.lastname: Sobotka