VITJ_FLAT format

The format of the multigroup data is essentially that of the MF=3 file of ENDF-6 format with the following deviations:

• The material number MAT consists of Z and two last digits of A. To indicate metastable targets MAT is increased by 50, 70 or 80 (for m1, m2 or m, respectively).

• The identifiers LIS and LFS are used to indicate states (isomers) of a target and final nucleus, respectively. The convention is: LFS=99 means total production cross-section; LFS is 0 for the ground state, 1 for m1, and 2 for m2. The reaction number (MT)  is that of ENDF format, except that MT for reactions leading to metastable states are increased by 300 and 600 (for m1 and m2, respectively). If the data for isomer production are present, the standard MT (as in the ENDF format) denotes cross section for production of the ground state only ('g' not  'm+g').

Just as in the EAF datafiles the reaction to the ground state is given first and followed by the reactions to the metastable states (if any).