Absolute cross sections for proton-induced fission of the uranium isotopes

Anomalous behavior of the proton-induced fission cross sections ofU235andAjitanand1, Iyengar2, Anand3 et al. 1987Phys. Rev. Lett.5000View full textAdd to dashboardCite

“…The errors shown were obtained by our compounding the statistical error with an estimated 20% error due to uncertainties in detection efficiency, number of incident protons, and target strength. The present measurements at 4 MeV agree with the extrapolated trends of the measurements of Boyce et al 5 and Kononov, Poletaev, and D'yachenko. 4 However, for lower energies there is a pronounced change in the trend of the excitation function so that the measured cross sections vary rather slowly with energy.…”

A treatment of medium-energy particle induced fission for spallation-systems’ calculations

“…The calculated values are systematically lower than measurement by about 30%; this is quite reasonable agreement on an absolute basis. The main fissioning nucleus is 239 Np but by 10 MeV proton energy multiple chance fission becomes significant; their contribution to fission at three proton energies as measured by Boyce et al [36] and calculated with EVAPF are shown in Table 5 and are in reasonably good agreement.…”

“…The values used are The values for the heights of the two barriers, the curvature energy for the ''A'' hump, the effective separation energy and the mean fission barrier have been determined by matching to measured data; the bulk of these results use direct reactions [32a-i] and measure fission probabilities starting from excitation energies well below the fission barrier to about 10 MeV. Results from neutron [35a-f] and proton [36] interactions have also been used. There are some marked differences in independent measurements of the same channel; in such cases separate matching was made to the results of each measurement and the one that gave parameters closest to the default starting conditions was accepted.…”

“…[35a-f] and protons [36] have provided the basic information to fix parameter values for the high atomic number nuclides part of the model. The closeness of parameter values to those obtained in the analysis of the experiments gives support for the simplified formulation.…”

Production of 234,235Np and 236Pu in bombardment of 236U with protons in the energy range from 17 to 40 MeV

“…In reactions in the actinide region the competition between fission and neutron evaporation of the compound nucleus is decisive in the formation of the end product. According to [8], the fission *Author for correspondence (E-mail: kerttuli.helariutta@helsinki.fi). probability increases stepwise as a function of incident proton energy from about 70% to about 80% from 16 MeV to 20 MeV.…”