The Group Structure of Cross-Section Libraries in Neutron Activation Spectrometry

Cross-section libraries and input neutron spectrum data are generally required in the application of activation neutron spectrometry and are usually given in the form of group values. Fine structures (620 groups for the energy range from 10^-10 to 18 MeV) are often used, but problems arise if adjustment codes implying matrix calculations are adopted. In this Note, the errors deriving from the use of a coarse (40-group) structure are estimated and discussed making special reference to a fast neutron spectrum.