Measurement of the~( 236)U(n, f) Cross Section in the Neutron Energy Range from 0.5 eV up to 25 keV

摘要

The~(236)U(n,f) cross section has been measured in the energy range from 0.5 eV to 25 keVat the Geel Electron Linear Accelerator neutron time-of-flight facility of the Institute for Reference Materials and Measurements in Geel, Belgium. A highly enriched~(236) U sample was mounted back-to-back with a~(10)B sample in the center of a Frisch-gridded ionization chamber, hence realizing a 2π detection geometry. A ~(235)U(n,f) cross-section control measurement was performed in the same experimental conditions. Special attention has been given to the fission resonance integral I_f and to the strongest resonance at 5.45 eV, for which a resonance analysis has been performed yielding Γ_f = 1.7 μeV. Both values are highly overestimated in the literature.