Nuclear data

Nuclear data represents all of the requisite nuclear physics parameters that are required for various applications. FISPACT-II has a variety of modern nuclear data forms that include reaction cross-sections, emitted particle spectra and angles, residual nuclide production, fission yields and radioactive decay data. The sub-pages linked below include user-friendly interfaces that allow users to find any of the nuclear data used by FISPACT-II and obtain detailed graphical representations of the data. Included for some data forms are interactive plotting tools which allow direct interrogation of the nuclear data values and comparison between data libraries, as well as options to download the original data files.


The set of nuclear data libraries distributed with FISPACT-II is available for download from the downloads page. This includes the standard library packages required for most usage cases, as well as special libraries for different temperatures, energy group discretisations and PKA matrices.

High-Energy Yields

High-energy reactions, above a few 10s of MeV, produce a large number of residual product nuclei through a combination of reaction phases that are typically described through an intra-nuclear cascade followed by pre-equilibrium emission and final de-excitation. Due to the relatively large number of reaction channels, this cannot be described in the standard ENDF-6 mt formalism. In a format analogous to fission yields, high-energy residual product libraries utilise the MF=10 format to specify the residual product cross sections for all possible products.

The High-Energy INCL-based Residual (HEIR) product library has been developed to provide this high-energy residual data for FISPACT-II calculations. It is distributed with FISPACT-II release 4.0, with proton-induced data up to 1 GeV. Films showing the data for all targets and energies are provided on the above page.

Fission Yield Data

Along with incident-particle reaction data, FISPACT-II includes particle-induced and spontaneous fission yields from all major libraries as well as the GEF-generated GEFY fission yields. These cover a wide range of nuclides of charge Z=86-100 with more than 100 total targets and a fine incident energy grid with up to 59 energies. A set of UKFY-4 files for charged particle induced fission are also provided, as well as spontaneous fission yields from all major evaluations and the GEFY files.