Mission
Science & Engineering
Collaboration
Community
Environment
Released: 2025-09-11
On August 30, 2024, the National Nuclear Data Center (NNDC) released the ENDF/B-VIII.1 nuclear data library. The files provided in the neutron sublibrary were processed into ACE-formatted files, verified, and validated, resulting in the Lib81 nuclear data library. This library contains files processed at 8 temperatures, including 6 that match the first 6 temperatures of the previous library Lib80x plus two additional.
| Temperature (K) | ZAID Extension |
|---|---|
| 293.6 (Room Temperature) | 0.10c |
| 600 | 0.11c |
| 900 | 0.12c |
| 1200 | 0.13c |
| 2500 | 0.14c |
| 0.1 | 0.15c |
| 233.15 | 0.16c |
| 273.15 | 0.17c |
N. Gibson, T. Saller, W. Haeck, N. Kleedtke, D. Neudecker, "Release of Lib81: ENDF/B-VIII.1-Based ACE Data Files for Neutron Transport," Los Alamos National Laboratory Memorandum XCP-5:25-022 (2025). LA-UR-25-29061
Documentation for the erratum Pt-Ta-Lib81:
A. Lewis, W. Haeck, N. Gibson, N. Kleedtke, "Lib81 ACE neutron sublibrary erratum for 190-198Pt and 180mTa," Los Alamos National Laboratory Memorandum XCP-5:26-011 (2026). LA-UR-26-24142
Lib81 can be downloaded either as a zip file or as a compressed tarball
Date: 2026-06-15
Name: Pt-Ta Lib81
Description: After the release of the Lib81 library, a problem was found in the neutron capture gamma spectra for 190-198Pt and 180mTa. This issue was due to the inclusion of discrete primary gammas for the capture reaction using a format that NJOY2016 did not support. (NJOY2016 supported the format used in the recent JENDL library releases.) More information about the format issue and the fix are documented in LA-UR-26-24142, included in the erratum and linked above.
If further information is required contact a member of the Data Team by e-mail at nucldata@lanl.gov