Light nuclides produced in the proton-induced spallation of U 238 at 1 GeV

The production of light and intermediate-mass nuclides formed in the reaction $^{1}\mathrm{H}+^{238}\mathrm{U}$ at 1 GeV was measured at the Fragment Separator at GSI, Darmstadt. The experiment was performed in inverse kinematics, by shooting a 1 A GeV $^{238}\mathrm{U}$ beam on a thin liquid-hydrogen target. A total of 254 isotopes of all elements in the range $7\ensuremath{\le}Z\ensuremath{\le}37$ 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.