Spectrum of Delayed Neutrons from the Thermal-Neutron Fission of Uranium-235

Measurements of the spectra of delayed neutrons from the thermal fission of 235U are reported over the energy range 30 to 1500 keV. The resolution is sufficient to identify locations of peaks in the spectra. Spectra for three different count-irradiation cycles are reported with the shortest representing a near equilibrium spectrum for delayed neutrons from 235U. Comparisons with existing data show relatively good agreement to the spectral peaks. A correction for the shield of the detector is introduced and applied to the current and previous work with reasonable results. In general, the new spectra are softer than previously reported and show more detailed structure.