Linearization and Resonance Reconstruction

Most NJOY processing sequences start with RECONR. It fills two roles. First, it goes through all the reactions included on the ENDF tape and chooses a union grid that allows all cross sections to be represented using linear interpolation to a specified accuracy. This step removes any nonlinear interpolation ranges (e.g., log-log, linear-log). It also makes it possible for all summation reactions to be reconstructed as the sum of their parts (e.g., total, total inelastic, total fission). Second, for resonance materials, it reconstructs the resonance cross sections (elastic, fission, capture) on a union grid that allows them all to be represented within certain accuracy criteria, and then combines the resonance data with the other linearized and unionized cross sections. The results are written in PENDF format.

RECONR is fairly easy to use. Issues that deserve more discussion include:

  • Linearizarization and Unionization - how are the energy grids chosen?
  • Resonance Reconstruction - what options are available?
  • Integral Thinning - practical libraries vs full accuracy.
  • Numerical Precision - how many significant figures are used to represent energies and cross sections?
  • Unresolved Treatment - how does RECONR interact with UNRESR and PURR?
They will be discussed on the pages to follow.


23 January 2013 T-2 Nuclear Information Service