Nuclear data evaluation effort

The FRIB nuclear data evaluation effort provides current, accurate, authoritative data for workers in pure and applied areas of nuclear science and engineering, and to address gaps in the body of available data through targeted experimental studies and the use of theoretical models.

FRIB’s nuclear data evaluation effort was established in April 2015 under the U.S. Nuclear Data Program (USNDP). USNDP is funded by the U.S. Department of Energy Office of Science Office of Nuclear Physics. FRIB’s nuclear data evaluation effort contributes to USNDP primarily by compiling and evaluating experimental nuclear structure and decay data, directly measured or deduced, for two major databases:

  • ENSDF (Evaluated Nuclear Structure Data File) database: evaluate experimental data from journal papers, conference proceedings, lab reports, and thesis, and recommend the best values for each mass chain.
  • XUNDL (eXperimental Unevaluated Nuclear Data List) database: compile (unevaluated) data from current publications for each paper; provide rapid access to formatted data from latest publications; and serve as data repository for unpublished data.

FRIB evaluates nuclear data for the mass regions of A=31 to 44 and A=60 to 73 (excluding 62, 67-70, which are evaluated at other centers) assigned within the international network of Nuclear Structure and Decay Data (NSDD) evaluators, and compiles data from the most recent publications with the priority given to nuclear structure and decay data from FRIB.

In addition, the FRIB nuclear data evaluation effort takes the leading role in developing new utility and analysis codes for XUNDL compilation and ENSDF evaluation and in modernizing the legacy ENSDF codes. The codes are hosted at the International Atomic Energy Agency (IAEA)  and widely used by the NSDD evaluators during the stages of compilation, evaluation, validation, and dissemination. 

FRIB’s nuclear data evaluation effort provides data support to FRIB experimenters under the framework of the FRIENDS (FRIB Integral Experimental Nuclear Data Services) project as part of the FRIB Laboratory support to FRIB users. Data support through the FRIENDS project covers all existing experimental nuclear structure and decay. It includes:

  • services for data needs in the stages of proposal preparation,
  • data taking,
  • data analysis,
  • publication preparation (aiming to help FRIB users for fast publication), and
  • checking data in proposals submitted to the FRIB Program Advisory Committee.

FRIB will enable significant discoveries about the properties of rare isotopes and is expected to generate a large amount of nuclear structure and decay data. The FRIB nuclear data evaluation effort enhances these scientific discoveries by promptly compiling, evaluating, and disseminating all new data from FRIB. It also establishes procedures and guides researchers to prepare/publish data from FRIB accelerator operation in a proper format that is convenient for reading, extracting, and compiling.