Investigations on Emission Sources in Proton-Nucleus and Nucleus-Nucleus Collisions

University dissertation from Department of Physics, Lund University

Abstract: Emission sources in proton-nucleus and nucleus-nucleus collisions at intermediate energies have been studied. Pion excitation functions from the absolute threshold to 500 MeV have been measured with an ion beam of continuously varying energy with an energy resolution of 1 MeV. Total yields, angular distributions and target mass dependences are compared to QMD and BUU calculations. Proton/deuteron/triton ratios have been measured in p + Kr, 16O + Kr and 20Ne + Ar reactions with a continuously varying beam energy up to 500 AMeV. Experimental ratios are compared to calculations from statistical models as well as dynamical models. Statistical models fail to reproduce the experimental data, whereas the dynamical models are only able to reproduce the experimental if a final-state interaction is introduced via the coalescence prescription. It is also shown that entropy cannot be directly dtermined from these ratios. Correlation functions for two neutron, two proton and neutron-proton pairs as well as singles measuremnts have been measured simultaneously in the E/A = 45 MeV 58Ni-27Al reaction, and are compared to calculations from a statistical model.

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