Measurement of isotopic cross sections of spallation residues in 800 A MeVAu-197+p collisions

The spallation of Au-197 by 800 MeV protons was investigated in inverse kin ematics at GSI, Darmstadt, by use of a Au-197 beam bombarding a liquid-hydr ogen target. The fragment separator (FRS) was used to select and identify t he reaction products prior to beta decay. The individual production cross s ections and the kinematic properties of 380 isotopes for all elements betwe en mercury (Z = 80) and neodymium (Z = 60) have been measured. A comparison with a Monte-Carlo calculation based on the two-step model of the spallati on reaction is given. The isotopic cross-section distribution of iridium is otopes is compared to that resulting from the aluminium-induced fragmentati on of Au-197. The mean kinetic energies of the fragments are deduced from t he experimental data. The importance of the new data to improve our underst anding of the spallation mechanism is discussed. (C) 2001 Elsevier Science B.V. All rights reserved.