Calculation of effective cutoff energies taking into account scattering and higher resonances of filters

A refinement on the calculation of the effective cutoff energies of neutron filters has been made by taking into account the scattering and higher resonances of the filters. The effect of scattering is found to be considerable, especially in the case of resonance detectors. With Sm and Gd filters the higher resonances introduce marked deviations of the cutoff energies from those calculated without taking their effect into account. These two factors of scattering and higher resonances cause the epithermal neutron flux from the 1/E-spectrum to strongly affect the cutoff energies. (author)