Heavy target fragment yields in the interaction of 28 GeV protons with 238U

Abstract

The yields of target fragments from the interaction of 28 GeV protons with 238U have been measured, with special attention being given to those fragments with 160 ≤ A ≤ 200. From the measured fragment yields, isobarie production cross sections were calculated. Significant yields (σ(A) ~ 1–10 mb) of heavy target fragments (160 ≤ A ≤ 210) were found. These fragments are believed to be the non-fissioning survivors from the population of highly excited residual nuclei produced in the initial p-nucleus collision. A pedagogical calculation of the fission – particle emission competition shows how the initial highly excited heavy nuclei could evaporate ~20–50 particles while surviving fission competition.