The primary source for information on the ENDF format, or for information on the ENDF/B libraries, is the National Nuclear Data Center (NNDC) located at the Brookhaven National Laboratory (BNL). Point your browser at the following URL: http://www.nndc.bnl.gov/. Take the link called "ENDF" and experiment by downloading some ENDF data. Note that you can get small parts of an evaluation.

Now go back to the BNL homepage and select "Manuals," then "ENDF-102." You can download a particular chapter of the ENDF format manual in Postscript form for viewing or printing.

Another good source for information on ENDF formats, ENDF/B data, and evaluated data from other systems, such as JEF, JENDL, BROND, or CENDL, is the T-2 Nuclear Information Service. First, take the "Data" link. Then scroll down to "ENDF/B-VI Neutron Data." You will see an index to all the evaluations in ENDF/B-VI. Explore the data sets available for that material. When trying the "Interpreted ENDF data" option, investigate the online help available for the ENDF formats.

Go back to the T-2 Data page and select "Nuclear Data Viewer." Check in by typing your email address in the text field, then press "continue." Press the select button and drag down to select ENDF-neutron as the data type. Press "Continue." Scroll down to H and select it. press "Continue." Select "1a" and continue. Select "3 1 (n,total)" and continue. Scroll down to the bottom of the page, choose "PS Plot" or "GIF Plot" and press "Continue." You should then see a graph of the hydrogen total cross section.

You can go back and try some variations. For example, try to make a log-log plot showing the total as a solid line and the capture as a dashed line. Hint: use the "AddCurve" widget.

Other sources on online nuclear data include the NEA Data Bank, the IAEA Nuclear Data Centre, and the JAEA Nuclear Data Center.