ENDF/B

ENDF/B
Name	ENDF/B
Type	Nuclear data library
Developer	Oak Ridge National Laboratory; Brookhaven National Laboratory; Los Alamos National Laboratory
First release	1960s
Latest release	ENDF/B-VIII (2018)
Subject	Evaluated nuclear reaction data
Format	ENDF-6

ENDF/B ENDF/B is a comprehensive evaluated nuclear reaction data library developed for use in nuclear reactor design, radiation protection, and nuclear science. It serves as a standardized collection of cross sections, decay data, fission yields, and related quantities compiled by national laboratories and international collaborations. The library underpins simulations performed with codes originating at institutions such as Los Alamos National Laboratory, Oak Ridge National Laboratory, and Brookhaven National Laboratory.

History and Development

The project emerged from early coordination among United States Atomic Energy Commission contractors, linked to programs at Oak Ridge National Laboratory and Brookhaven National Laboratory during the 1950s and 1960s, and later integrated contributions from Los Alamos National Laboratory and international centers including NEA Data Bank participants. Major milestones paralleled developments in reactor programs like the Hanford Site and computational milestones at Lawrence Livermore National Laboratory and Argonne National Laboratory. Governance and peer review involved advisory groups with ties to the International Atomic Energy Agency and the OECD Nuclear Energy Agency, reflecting shifts in experimental facilities such as the Brookhaven Graphite Research Reactor and the High Flux Isotope Reactor. Periodic workshops and conferences at venues like Knoxville, Tennessee and Paris coordinated evaluations and version releases.

File Format and Data Structure

ENDF/B uses the ENDF-6 formatting conventions established to permit machine-readable, consistent presentation across institutions. The format ties to legacy formatting practices from early computing at Los Alamos National Laboratory and data systems developed at Brookhaven National Laboratory. Records are organized by material and reaction MT numbers, with sections linking to evaluated resonance parameters, angular distributions, and energy-dependent cross sections. The structure enables interfacing with processing tools such as NJOY, which itself was developed with collaborators from Lawrence Livermore National Laboratory and Argonne National Laboratory. Data sections reference specific experimenters and facilities like CERN experiments and measurements from the European Organization for Nuclear Research and national metrology institutes such as NIST.

Evaluations and Versions (ENDF/B-I to ENDF/B-VIII)

Releases proceeded through numbered versions reflecting expanded isotopic coverage and methodological advances. Early editions incorporated evaluations influenced by work at Brookhaven National Laboratory and Oak Ridge National Laboratory, while later editions integrated modern reaction models used at Los Alamos National Laboratory and international evaluations coordinated by the NEA Data Bank. ENDF/B-VII introduced extensive thermal scattering data and covariance formats influenced by programs at Knolls Atomic Power Laboratory and research outputs from Idaho National Laboratory. ENDF/B-VIII expanded on covariance data, improved neutron resonance evaluation practices developed in collaborations with Cadarache groups, and assimilated measurements from facilities such as Oak Ridge’s neutron sources and European research reactors.

Nuclear Data Types and Content

The library contains evaluated neutron, charged-particle, and photon-induced reaction cross sections, decay data, fission product yields, and thermal scattering law files. Specific data types include resolved and unresolved resonance parameters reflecting experiments at places like Los Alamos beamlines and analyses from Brookhaven measurement campaigns, angular distributions informed by scattering experiments at CERN and RIKEN, and prompt and delayed neutron spectra tied to fission research at Idaho National Laboratory. Covariance matrices and uncertainty quantification draw on methods developed in coordination with OECD Nuclear Energy Agency working groups and analysis techniques published by authors affiliated with Rutgers University and University of California, Berkeley research programs.

Applications and Usage in Reactor and Nuclear Science

ENDF/B data feed into deterministic and Monte Carlo transport codes developed at institutions including Argonne National Laboratory and Los Alamos National Laboratory and implemented in tools such as MCNP and SCALE, used for reactor core design at industrial partners like Westinghouse Electric Company and safety analysis at national sites including Hanford Site and Savannah River Site. Nuclear astrophysics applications connect evaluated cross sections to studies at observatories and laboratories such as TRIUMF and GSI Helmholtz Centre for Heavy Ion Research. Medical isotope production planning relies on cross-section data from ENDF/B in workflows at facilities like Brookhaven and Oak Ridge. Criticality safety engineers at consortia including Nuclear Regulatory Commission contractors use processed libraries for licensing and regulatory assessments.

Distribution, Access, and Maintenance

Distribution is managed through national laboratory portals and collaborative repositories maintained by Brookhaven National Laboratory and coordinated with international services like the NEA Data Bank and data exchange mechanisms supported by the International Atomic Energy Agency. Maintenance involves periodic validation against integral benchmark suites such as those cataloged by the International Criticality Safety Benchmark Evaluation Project and collaborative verification studies with contributors from Lawrence Livermore National Laboratory and European evaluation teams. User support and processing utilities are provided by communities centered at laboratories and universities including Oak Ridge National Laboratory, Los Alamos National Laboratory, and academic groups at Massachusetts Institute of Technology and University of Michigan.

Category:Nuclear physics Category:Nuclear data libraries