Measurement of the complete nuclide production and kinetic energies of the system 136Xe + hydrogen at 1 GeV per nucleon

We present an extensive overview of production cross sections and kinetic energies for the complete set of nuclides formed in the spallation of 136Xe by protons at the incident energy of 1 GeV per nucleon. The measurement was performed in inverse kinematics at the FRagment Separator (GSI, Darmstadt). Slightly below the Businaro-Gallone point, 136Xe is the stable nuclide with the largest neutron excess. The kinematic data and cross sections collected in this work for the full nuclide production are a general benchmark for modelling the spallation process in a neutron-rich nuclear system, where fission is characterised by predominantly mass-asymmetric splits.Comment: 18 pages, 14 figure

Fission and cluster decay of 76^{76}Sr nucleus in the ground-state and formed in heavy-ion reactions

Calculations for fission and cluster decay of $^{76}Sr$ are presented for this nucleus to be in its ground-state or formed as an excited compound system in heavy-ion reactions. The predicted mass distribution, for the dynamical collective mass transfer process assumed for fission of $^{76}Sr$, is clearly asymmetric, favouring $\alpha$-nuclei. Cluster decay is studied within a preformed cluster model, both for ground-state to ground-state decays and from excited compound system to the ground-state(s) or excited states(s) of the fragments.Comment: 14 pages LaTeX, 5 Figures available upon request Submitted to Phys. Rev.

Light Nuclides Produced in the Proton-Induced Spallation of 238U at 1 GeV

The production of light and intermediate-mass nuclides formed in the reaction 1H+238U at 1 GeV was measured at the Fragment Separator (FRS) at GSI, Darmstadt. The experiment was performed in inverse kinematics, shooting a 1 A GeV 238U beam on a thin liquid-hydrogen target. 254 isotopes of all elements in the range from Z=7 to Z=37 were unambiguously identified, and the velocity distributions of the produced nuclides were determined with high precision. The results show that the nuclides are produced in a very asymmetric binary decay of heavy nuclei originating from the spallation of uranium. All the features of the produced nuclides merge with the characteristics of the fission products as their mass increases.Comment: 40 pages, 16 figures, 3 table