There are four photon transport libraries maintained by X-5 and distributed with MCNP: MCPLIB, MCPLIB02, MCPLIB03 and MCPLIB04.
The official version of MCPLIB  is unchanged since 1982. Versions of MCPLIB existed prior to 1982. MCPLIB contains data from several sources. For Z equal 1 to 94 (excluding Z equal 84, 85, 87, 88, 89, 91, 93), the cross section data for incident energies from 1 keV to 100 MeV and all form factor data are from the ENDF/B-IV evaluation, which is available from RSICC as data package DLC-7e. The excluded elements are tabulated only on the energy range from 1 keV to 15 MeV and trace their cross section data back to the Storm and Israel 1970 data compilation , which is available from RSICC as data package DLC-15. The form factor data for the excluded elements is of forgotten origin. The fluorescence data were produced by Everett and Cashwell  from the Storm and Israel 1970 data, supplemented as necessary. MCPLIB does not contain momentum profile (CDBD) data.
MCPLIB can be downloaded either as a zip file or as a compressed tarball
If further information is required contact a member of the Data Team by e-mail at firstname.lastname@example.org