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Available tallies

Publié le 29 novembre 2018

variety of tallies are available:

  • averaged flux in a volume (as obtained by either track-length or collision estimators),
  • surface flux and current,
  • point flux,
  • reaction rates (including activation cross-sections from EAF evaluation files and dosimetry cross-sections from IRDF evaluation files),
  • pulse-height for gamma spectroscopy,
  • dose equivalent rates,
  • fission spectra
  • particle production rates.


Additional tallies are specific to the criticality simulation modes:

  • the keff eigenvalue,
  • the Kij fission matrix,
  • the neutron importance function,
  • the kinetics parameters, such as the delayed neutron fraction beff and the neutron generation time Leff (which involve weighting by the critical adjoint flux)
  • Reactivity perturbations
  • Sensitivities of the keff eigenvalue to nuclear data.


Most volume-averaged tallies can also be requested on user-defined meshes and can be further decomposed as a function of the material compositions intercepted by the spatial meshes.

Moreover, a number of tallies dedicated to the irradiation of materials are also available:

  • The energy separately deposited by neutrons, photons, electrons and positrons, including photo-atomic as well as photonuclear reactions when available. Energy deposition for each transported particle is computed by resorting to the 'energy balance' method; when delayed particles are produced (neutrons, photons or betas), the user can choose to assume that these particles are either deposited locally or transported. When needed, the reaction Q-values are computed by mass defect. Concerning fission, the fission Q-value is either given by the user, or read in the nuclear data libraries according to the available information.
  • The kinematic limits for coupled neutron-photon calculations, which represent a sort of confidence interval for assessing the reliability of the deposited energy score as computed from energy balance. This tool can be used to check the coherence of nuclear data (especially for possibly lacking or incomplete photon productions).
  • The displacements per atom (DPA), which are computed by resorting to the Norget-Robinson-Torrens model [1], including threshold effects due to the Kinchin-Pease model. The photon kick contribution (giving rise to nucleus recoil energy) is also taken into account. The necessary displacement energies for each nucleus or material must be provided by the user.
  • The gas production, which can affect materials (especially steel) by inducing embrittlement under irradiation. The production rate of light isotopes, including hydrogen, deuterium, helium-3 and alphas, is computed by resorting to a mass balance principle. The neutron and photon (via photonuclear reactions) contributions are separately computed. Light particles coming from (typically ternary) fission are included by reading the corresponding fission yields in nuclear data libraries.


[1] M. J. Norgett, M.T. Robinson, I.M. Torrens, Nuclear Eng. Design 33, 50 (1975).