in support of CRP Primary Radiation Damage Cross Sections
Motivations/PurposesMeeting is organized to implement the Recommendation of RCM-2 (see INDC(NDS)-0691, Section III.4):
"4. We need to improve the accuracy and consistency of PKA spectra, including recoils from the neutron absorption reactions. Differences are seen currently between different evaluations. We need to try to establish the most reliable data, and this would be recommended by CRP, and provide a quantitative uncertainty estimate.
Uncertainties are needed for the PKA spectra, KERMA, gas production and damage energy. PKA spectra are derived from all nuclear reactions, so their uncertainties are affected by the accuracy of the neutron cross section total and spectral data. Methods for their estimation should be established.
The IAEA NDS should organize a meeting to address these issues."
Following these purposes, the specific issues to be addressed are:
- The energy spectra of the Primary Knocked-out Atoms (PKA) are the starting point for the consequent damage energy and displacement cross sections calculations.
However, as was shown, the PKA spectra derived from the main evaluated neutron cross section libraries (ENDF/B-VII.1, JENDL-4, JEFF-3.2, TENDL-2014, ...) are different.
The notable deviations among them were observed already at neutron energies of a few MeV, and essentially increase at 14 MeV and higher energies, where multiple emission reactions such as (n,2n) open.
- recommendation of the most reliable calculation models and selection of representative (to serve as a reference) evaluated files of PKA spectra
- uncertainties of PKA: how generate them and there is a sense to store them in files?
- The kinematic energy deposition in materials (KERMA factors) calculated from the PKA spectra using various evaluations consequently also disagree (up to factor of 2).
Calculated KERMA do not always agree with the existing experimental data (list of published KERMA measurements until they will be compiled in EXFOR).
- calculation and validation of KERMA against measurements to recommend the reliable evaluation
- uncertainties of KERMA ...
- Damage Energy and NRT-/arc-Displacement cross sections
- calculation using various evaluated libraries, quality inspection to recommend the most reasonable evaluation
- impact of ions stopping power, energy partion function and their uncertainties on NRT- and arc-dpa
- impact of the primary defect surviving function and its uncertainties on arc-dpa and rpa, see Collection of Efficiencies
- models defects ?
- resultant total uncertainties ...
- Uncertainties/covariances for Gas production cross sections
- calculation and validation against measurements to recommend the reliable evaluation
- uncertainties ...
- Methods to assess the Uncertainties for abovementioned quantities:
- deduce from the cross section covariances data available for the basic reaction channels in the evaluated libraries
- use a Total Monte Carlo (TMC) analysis which allows the non-linear uncertainty propagation from the model-based variation in the TALYS cross sections (Random Files) into the kerma and displacement components
- Evaluated Libraries to use and Materials of Interest:
- ENDF/B-VII.1, JEFF-3.2, JENDL-4.0, TENDL-2014, TENDL-2015, FENDL-3, ROSFOND, DXS, CIELO at IAEA, CIELO at NEA
- Materials: see web-page of CRP on Primary Radiation Damage Cross Sections