US-Federal Republic of Germany Cooperative Research: Bombarding Energy Dependence of Multi-fragmentation

点击翻译按钮获取中文摘要

This award supports Drs. William G. Lynch, C. Konrad Gelbke and others of Michigan State University to collaborate in physics research with Drs. Uli Lynen, W. Trautmann and J. Pochodzalla of the University of Frankfurt and the Gesellschaft fuer >Schwerionenforschung (GSI) at Darmstadt, FRG. They are >investigating the properties of multifragment breakup mechanisms in order to obtain information about the equation of state and liquid.gas phase transition of dilute nuclear matter. MSU has a compact and highly granular intermediate mass fragment detection array, the MINIBALL. Measurements with this device require small halo.free Krypton beams at an energy level and quality not available in the U.S. Such beams will be available in the near future at GSI, which will be the best facility of its kind in the world; however, there is no array similar to MINIBALL at GSI. The collaboration, therefore, is based on transporting the array to Germany to bring these two complementary state of the art devices together. Calculations suggest that multifragmentation may occur in heavy ion reactions over a wide range of incident energies. Few measurements to date have addressed the properties of collisions which lead to the production of many intermediate mass fragments. MINIBALL was constructed to look for intermediate mass fragments and provide information about highly excited and dilute nuclear matter. In conjunction with the ALADIN spectrometer, it will be possible to measure multifragmentation processes for Krypton induced reactions over the energy range 50 to 1000 MeV. Studies in this range will complement the ongoing research effort at MSU where reactions at lower energies are being explored. The results of their initial survey of the Kr.Nb system will have a significant impact on the directions of subsequent heavy ion experiments. Once incident energies at which multifragment breakup mechanisms are dominant have been identified, detailed comparisons to dynamical and statistical multifragmentation models will be performed.