Lib81: ACE Nuclear Data Library based on ENDF/B-VIII.1 Neutron Sublibrary

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

Documentation

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