190 MeV proton-induced symmetric and asymmetric fission

Proton-induced fission ($E_{\mathrm{p}}=190\mathrm{}$ MeV) has been studied for uranium and selected nuclei, $140\lesssim A\lesssim 200$. Analysis of coincident-fragment energies suggests highly asymmetric fission near $A=140\mathrm{}$, 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.