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Points of Attention

⚠️ Important Considerations (read this section along with the Theory chapter and examples in USER_EXAMPLES.ipynb)

Special Isotope Handling

  • Bounded isotopes: Some isotopes in sensitivity files are not present in variance-covariance matrices. TSURFER (SCALE) uses data from the closest isotope, and CALINS detects these cases when the hundreds digit of the ID is ≥ 3:
  • be-9 bounded (ID=4309 or 4509) → associated with covariances of be-9 (ID=4009)

  • h-1 bounded (ID=1901 or 1801) → associated with covariances of h-1 (ID=1001)

  • Natural isotopes: Isotopes with 'natural' evaluated forms:

  • c-12 bounded (ID=6312) → associated with covariances of c-0 (ID=6000)

Reaction ID Considerations

  • CAPTURE vs N,GAMMA: Some covariance matrices have data for CAPTURE reaction (ID=101), others for N,GAMMA reaction (ID=102), which are very close. Be careful when associating these reactions.

  • MCNP negative IDs: SDF files from MCNP calculations can contain reactions with negative IDs:

  • CALINS associates reaction -2 to reaction 101 if the mcnp=True flag is enabled when creating the Case object
  • Other negative reactions trigger a warning

Sensitivity Profile Occurrences

When an SDF file has multiple sensitivity profiles for the same isotope-reaction pair (same IDs), TSURFER (SCALE) parses profiles differently. CALINS provides three rules: - occurrences_rule='first': Use the first occurrence as the sensitivity profile - occurrences_rule='sum' (default): Sum all occurrences for the profile - occurrences_rule='last': Use the last occurrence