A number of neutron spectra are provided for comparison and for data verification and validation purposes. The spectra are given in ENDF-6 format under file MF=3 and reaction MT=261. They are differentiated by the MAT number.

The ENDF column provides the link to the spectrum in pointwise form (where applicable). The GENDF column gives the link to the group-averaged spectrum. Some spectra are given in the extended SAND-II structure of 640-groups spanning the energy range 1E-4 eV to 20 MeV, others cover the energy range 1.e-5 eV to 60 MeV. In a few cases the number of groups is smaller because the groups with zero-spectrum value are suppressed. All group spectra are compatible with the 640-group SAND-II structure, except the CFRMF spectrum (MAT=9005), which was adopted from IRDF-2002 for historic reasons.

The link in the column "RR_UNC" leads to the listing or reaction rate integrals and the associated uncertainties obtained with the RR_UNC code. The listing includes the median energy of the reaction, thetotal (absolute) uncertainty and the relative (percent) uncertaities due to the cross sections, the spectrum and the total uncertainty.

The link in the column "Spectrum" leads to the plot of the spectrum and the cumulative reaction rate integrals, which provides a indication of the energy region that contributes most to the integral.

The link in the column "Description" leads to the extract of the comments in the spectrum ENDF file.

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Note that (**) refer to spectra not recommended as benchmark spectra.