Experimental Evaluation of Minima in the Total Neutron Cross Sections of Several Shielding Materials

Neutron total cross sections in the energy range from 1 to 11 MeV have been experimentally evaluated for several shielding materials by comparing calculations and measurements of the spectra of the uncollided flux transmitted through thick samples. This technique provides a critical test of the minima in the cross sections but yields little information about the resonance regions. Special emphasis has been placed on evaluating the total cross sections in the Evaluated Nuclear Data File (ENDF/B), which, in most cases, are the best available, the exceptions being for iron and tungsten.