ID 54
Type S - Special purpose quantity
Sub type DOS - Dosimetry
Target 25-Mn-55
Reaction (n,g)
Quantity SIG/SPA - Cross section averaged over an incident particle energy spectrum
Incident energy 235U(n,f)
Accuracy 2-5 %
Field(s) Dosimetry
Subfield Fast fission, D-T fusion
Accepted date 06-Oct-2017
Status Work in progress
Latest review date 28-Apr-2022


Dr Stanislav SIMAKOV at KIT, GER

Project (context)

IRDFF project


The International Reactor Dosimetry and Fusion File (IRDFF) aims at providing evaluated neutron dosimetry reactions validated for all applications related to fission reactors and fusion technology development [IAEA2017].



Justification document

Accurate cross sections as well as spectrum-averaged cross sections (SACS) in relevant and well-characterized neutron fields are essential for improvement and validation of the evaluated data [Simakov2017].

Comment from requester

New measurements of the spectrum-averaged cross section are requested to solve C/E discrepancy. See SPA_CE_U235.pdf below.


  • [IAEA2017] IAEA CRP on Testing and Improving the International Reactor Dosimetry and Fusion File (IRDFF),
  • [Simakov2017] S. Simakov, et al., “Proposals for new measurements for IRDFF community and HPRL”, September 2017.


Review comment

Non-threshold reactions measured in fast spectra such as the 252Cf(sf) and 235U(nth,f) spectrum tend to have their spectrum averaged cross section dominated by scattering contributions and ‘room-return’ neutrons. Experiments should be designed to minimize these contributions and maximize the reaction rate from the primary source. For new experiments best estimates must be provided by detailed Monte Carlo calculation of the spectrum realized in the experiment and the Monte Carlo model must be made available to IRDFF to facilitate validation of new proposals for the cross section. In all cases it is advised to publish both the fully corrected SACS and the measured reaction rates of the primary reaction and the monitor reactions used for normalization and validation of the model. The measured reaction rates must be provided with a full covariance matrix.

Entry status

Work in progress (as of SG-C review of May 2018)

Main recent references

Please report any missing information to hprlinfo@oecd-nea.org