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The Uranium-233 Fission Neutron Spectrum from 0.8 to 10 MeV

L. Green, J. A. Mitchell, N. M. Steen

Nuclear Science and Engineering / Volume 52 / Number 3 / November 1973 / Pages 406-412

Technical Note / dx.doi.org/10.13182/NSE73-A19488

The 233U fission neutron spectrum has been measured by pulsed-beam time-of-flight techniques from 0.8 to 10 MeV. Above ≈2 MeV, the data were found, within statistics, to be adequately represented by either the model in the ENDF/B-III file or a best fit Maxwellian distribution with nearly the same average energy. At lower energy, the data appear to follow the ENDF/B representation somewhat more closely. The fit of a Maxwellian distribution to the 233U data yielded an average “temperature” parameter of 1.34 ± 0.02 MeV, where the error includes both statistical and systematic uncertainties. A similar fit to data taken for a 235U sample yielded a temperature parameter of 1.31 ± 0.03 MeV; however, the best estimated difference in temperature is 16 ± 6 keV.