The National Nuclear Data Center (NNDC) collects, evaluates, archives and disseminates nuclear physics data for basic nuclear research and for applied nuclear technologies. The Center collects experimental information on nuclear structure and nuclear reactions, evaluates them employing nuclear physics theory and expertise in evaluating experimental techniques to provide recommended results, maintains nuclear databases and using modern information technology disseminates the results. The data are kept in dedicated libraries, which are periodically updated. The information is the product of the NNDC-coordinated US Nuclear Data Program that involves several National Laboratories and Universities, as well as, cooperating data centers and other interested groups worldwide. There are two other major data banks operated by international organizations, one in Paris and another in Vienna.
The NNDC has provided data and expertise to the world community for more than a half-century, tracing its roots back to 1952, when the Brookhaven Neutron Cross Section Compilation Group was formed in the Physics Department. This group published the first edition of the well-known reference book BNL-325 (Neutron Cross Sections) in 1955. The group’s name was changed to the Sigma Center in 1961, then to the National Neutron Cross Section Center in 1967 and finally to the NNDC in 1977, when it was given the additional responsibility for nuclear structure and decay data. Since 1977 the NNDC is coordinating the worldwide nuclear structure and decay data effort, which produces the unique Evaluated Nuclear Structure Data File (ENSDF).
Over the last ten years the group has made essential advances bringing nuclear data effort into the 21st century. The group introduced the next generation of computer services and, at present, the NNDC provides the only US Web portal distributing the widest possible range of nuclear data to all users. As an integral part of its activities, the NNDC is improving evaluation methodology through development of nuclear reaction code system implementing modern nuclear reaction theory. Importance of nuclear data uncertainties and their correlations have recently been recognized and the new field is being very actively pursued. In recent years, the NNDC has expanded its activities to include experiments specifically related to nuclear data.
A new version of the ENDF nuclear reaction library, released in 2011, contains data used in nuclear physics simulations supporting energy, security, medical and shielding applications.
The NNDC libraries are often used by the general public, not just by scientists. There has been a considerable increase in nuclear structure and decay data retrievals following the Fukushima accident. The services provided by the Center also attract attention of the physics educators. The NNDC has the most accessed website at BNL, besides the Laboratory home page. In 2006, NNDC reached an important milestone of “1 million” Web-based database retrievals while in 2012 this number approached nearly 3 million. The NNDC Web portal has steadily improved over the years, making it one of the most user friendly in the field. Improvements continue to be deployed as the NNDC continues in its role as the leading data dissemination center supporting both nuclear research and applications.