Sigma Advanced Retrieval Help

The Advanced Retrieval form allows to retrieve data stored in ENDF format from 4 different libraries: ENDF/B-VII.0 (USA, 2006), JEFF 3.1 (Europe, 2005), JENDL 3.3 (Japan, 2003) and ENDF/B-VI.8 (USA, 2001).

The use of this form requires some knowledge of the ENDF format. Alternatively, the need to know ENDF has been minimized in the Basic Retrieval page.

Users can specify the target using the "Target", "Z" and "A" inputs. For instance, 232Th can be determined as:

  • , or
  • , or

The retrieval for 2 or more target nuclei can be achieved using "," (comas) or ";" (semicolons) to separate the nuclei names. For instance, a retrieval for 236U and 238Pu is performed using:

The following examples explain how ranges can be specified:

  • Search for Th isotopes:
    • , or


  • Search for A=240 isotobars:

  • Search for Z=90 to Z=94 isotopes:

  • Search for A=230 to A=244 isotopes:

Following the Target/Z/A inputs, one needs to choose the MF and MT values. A given library in the ENDF format is divided in sublibraries. Each sublibrary is made up of individual files corresponding to a given target. The files are divided in sections specified by two labels, MF and MT. The former are used to determine the type of quantity, for instance MF=3 is used for cross sections, while the latter are used to specify the reaction, for instance, MT=102 is used for capture cross sections. Valid entries for the MF and MT text boxed should be integer positive numbers.

The "Browse MF" and "Browse MT" buttons can be used to the MF and MT values corresponding to a given quantity and reaction.

The final two sections of the form deals with the selection of the sublibrary and the libraries. An effort was made to translate the original ENDF labels into readable expressions.

The following examples will illustrate a few typical retrievals:

  • Neutron capture cross sections on Pb isotopes from the ENDF/B-VII.0 and JEFF 3.1 libraries:
  • Neutron cross sections standards, note that because there are so few of them, one can leave the Target/Z/A inputs empty:

    For similar reasons, the target doesn't have to be specified when searching for covariances, nu-bars and fission yields.
  • Proton cross sections from ENDF/B-VII.0 in the Z=20-40 range:

If you have questions about Sigma, please don't hesitate to contact us.