Experimental study on the production of light nuclei in spallation–fission reactions and projectile fragmentation of 238U Original Research Article

With the inverse kinematics method, the reaction mechanism which leads to the formation of light nuclides was investigated with a 1 A GeV 238U beam impinging on a liquid H2 target. Isotopes of all elements with Z⩾6 were unambiguously identified, and the velocity of every produced nuclide was measured with great precision. Results show that very asymmetric fission of uranium nuclei produces neutron-rich isotopes of elements down to around charge 10. When uranium interacts with heavier nuclei the features of the reaction change drastically: while fission is the main mechanism for the production of light masses in 1 A GeV 238U on H2, projectile fragmentation plays a dominant role in 1 A GeV 238U on Ti leading to the formation of stable or neutron-deficient isotopes of all elements.