190 MeV proton-induced symmetric and asymmetric fission

Proton-induced fission (Eₚ=190 MeV) has been studied for uranium and selected nuclei, 140A200. Analysis of coincident-fragment energies suggests highly asymmetric fission near $A=140$, even in the presence of relatively high fission barriers. The data have been compared with statistical-model fission calculations modified to include precompound nucleon emission. The data can be reproduced using standard fission-barrier and level-density parameters.NUCLEAR REACTIONS Fission, ⁿᵃᵗU, ¹⁹⁷Au, ¹⁶⁹Tm, ¹⁵⁹Tb, ⁿᵃᵗCe(p, f). $E=190$ MeV; measured σf (90^∘{}), angular correlations, coincident fragment energies. Deduced mass division, total kinetic energy release, fission cross sections; compared with statistical-model fission calculations.