[en] 1 - Description of program or function: SIXPAK has two main functions: (1) check all double-differential ENDF-6 format data (MF=6); (2) output equivalent uncorrelated data (MF = 4, 5, 12, 14,and 15 data. IAEA1283/06: This version include the updates up to January 30, 2007. Changes in ENDF/B-VII Format and procedures, as well as the evaluations themselves, make it impossible for versions of the ENDF/B pre-processing codes earlier than PREPRO 2007 (2007 Version) to accurately process current ENDF/B-VII evaluations. The present code can handle all existing ENDF/B-VI evaluations through release 8, which will be the last release of ENDF/B-VI. Modifications from previous versions: - Sixpak Vers. 2007-1 (Jan. 2007): checked against all ENDF/B-VII; increased maximum table size from 12,000 to 120,000. 2 - Method of solution: All of the ENDF-6 MF=6 data is checked. The MF=6 data is not corrected and output in the ENDF/B format is merely checked. If errors are found it is up to the user to take corrective action on the MF=6 data. In contrast, when problems are found in data which will be output in the ENDF/B format (MF=4, 5, and 15), corrective action will be taken, whenever possible. SIXPAK changes correlated (MF=6) vs. uncorrelated (MF=4 and 5) data. The ENDF/B double differential correlated data in MF=6 represent data in the form F(E,EP,COS) = SIG(E)*Y(E)*G0(E,EP)*F(E,EP,COS) with: SIG(E) = MF=3 cross sections; Y(E) = yield (multiplicity); G0(E,EP) = energy spectrum; F(E,EP,COS) = angular distribution. The uncorrelated data produced by this code replaces the correlated data by the uncorrelated data, F(E,EP,COS) SIG(E)*Y(E)*G0(E,EP)*F0(E,COS) by integrating G0(E,EP)*F(E,EP,COS) over secondary energy (EP) to define an average angular distribution, F0(E,COS). What is lost in this process is the correlation between EP and COS so that in a transport calculation all moments of the flux will have the same spectrum, G0(E,EP) and each will be effected by the average angular distribution. Three ENDF/B formatted output files are produced for neutron incident data: 1) ENDFB.MF4 - angular distributions and Legendre coefficients; 2) ENDFB.MF5 - tabulated neutron energy spectra; 3) ENDFB.M12 - photon emission multiplicity; 4) ENDFB.M14 - photon emission angular distributions (always isotropic). All of this data is in normalized form suitable for use with the cross sections in MF=3. 3 - Restrictions on the complexity of the problem: This program only uses the ENDF/B BCD or card image format (as opposed to the binary format) and can handle data in any version of the ENDF/B format (i.e., ENDF/B-I, II,III, IV, V or VI format). It is assumed that the data is correctly coded in the ENDF/B format. No error checking is performed. All of the data in ENDF-6 MF=6 are quite small tables. As such this program only allows tables of up to 6000 points (6000 x and y values). This size is more than adequate to handle all of the current ENDF/B-VI data, and it can be easily increased to handle any newer data as it becomes available