This page presents the ACE formatted files for the 423 materials in the ENDF/B-VII.1 neutron reaction sublibrary and the 20 materials in the ENDF/B-VII.1 thermal neutron scattering sublibrary.   These files were generated by the NNDC using the processing code NJOY99.368 (except for Cl-35 which was generated using NJOY2010) as part of the Phase I testing (data verification) process.  In addition, all files for the neutron reaction sublibrary were generated at 293.6^oK. On the other hand, each file for the thermal neutron scattering sublibrary was generated at the lowest temperature, ranging from 19^oK to 296^oK, that the evaluation was performed.  However, the SiO₂ file could not be generated due to the unavailability of the corresponding NJOY input file at the time.

We want to ensure that ENDF/B-VII.1 provides the best possible data to our users. If you find any issues/deficiencies, please note them using either the neutron sublibrary issue tracker or the thermal scattering sublibrary issue tracker.

The following ENDF/B-VII.1 ACE sublibraries are only preliminary, and are not equivalent to those provided by the XCP Nuclear Data Team (LANL) and included in every release of the MCNP code.  Therefore, they are not recommended for use in real-world applications. As such, they are made available here as is and no technical support shall be provided by NNDC.  All queries should be directed to the XCP Nuclear Data Team.

TarGzip Files of Full Sublibraries

• Neutron Reaction Sublibrary (XSDIR file included)
  • Neutron Sublibrary at 293.6^oK
    Download checksums:

    MD5:	9729a17eb62b75f285d8a7628ace1449
    SHA1:	54212defb4de5bdf904f567d2d90f731f890c007
    cksum:	2735111166

  • Neutron Sublibrary at 300^oK
    Download checksums:

    MD5:	283e9fc723127c5bc1ae529a9bb2caca
    SHA1:	5c14fab47c4e7014e8e7cd1f960cfbfff10fffbf
    cksum:	4204511879

• Thermal Neutron Scattering Sublibrary (XSDIR file included)
  Download checksums:

  MD5:	e17d827c92940a30f22f096d910ea186
  SHA1:	b4675a69b48676ae5c68a82740309a9db9a81fc5
  cksum:	149512800

ACE File Errata

(Dec 2014) An error was found in the previous version of these file: all ZAID's of isomer were incorrect, affecting 58m1Co, 110m1Ag, 115m1Cd, 127m1Te, 129m1Te, 148m1Pm, 166m1Ho, 242m1Am, 244m1Am, 254m1Es. The corresponding evaluations were updated with correct ZAID's as were the xsdir files. The ZAID's of isomers now follow the rule: Z*1000+A+300+100*m.

(Jan 2017) In the list of ZAIDs that the S(a,b) table applies to, both Be9 and O16 are listed when only one of them should be listed for each table. Inside a TSL ACE file is a list of ZAIDs that the table should be applied to. MCNP (and OpenMC and Serpent) use this list to decide what cross sections to modify in the thermal energy range. For Be in BeO, that list is [4009, 8016], meaning that the cross sections for Be9 and O16 will be modified by the table. The same list appears in the O in BeO file.

(Jan 2017) Benzine and graphite TSL files list 6012 rather than 6000, so if you are using the elemental C ACE file, you will need to change 6012 to 6000 in order to use the graphite S(a,b) table with it (same with benzine)

(Jan 2017) There are a few materials that are supposed to have incoherent elastic data (H in CH4 (solid), H in CH2, H in ZrH, Zr in ZrH) but do not in the TSL ACE files.