https://doi.org/10.1051/epjconf/202328100027
Experimental spectrum averaged cross sections (SACS) in 252Cf(sf) neutron field and its impact on the evaluation of neutron standards
1 NAPC–Nuclear Data Section, International Atomic Energy Agency, PO Box 100, A-1400 Vienna, Austria
2 National Institute of Standards and Technology, Gaithersburg, MD, USA
3 Commisariat a l’Energie Atomique, Cadarache, DEN/DER 13108 Saint-Paul-Lez-Durance, France
4 Los Alamos National Laboratory, Los Alamos, NM, USA
* e-mail: r.capotenoy@iaea.org
Published online: 29 March 2023
A new evaluation of spectrum averaged cross sections (SACS) of 235U, 238U, and 239Pu measured in the 252Cf(sf) reference neutron field is presented and found to be consistent with the original Mannhart SACS evaluation in IRDF-2002. The comprehensive vetted experimental database that includes SACS ratio and absolute SACS measurements of major actinides is being used to update the SACS database employed as input of the new GMApy code to derive the Neutron Standards. An update of the current neutron standards based on Time Projection Chamber (TPC) shape data, a new comprehensive uncertainty quantification, and revised SACS experimental database is proposed which result in a 0.7% increase of the evaluated 239Pu(n,f)/235U(n,f) crosssection ratio in the 1–5 MeV energy region. The increase is due to a 0.3% reduction of the standard 235U(n,f) cross section and a 0.4% increase of the 239Pu(n,f) reference cross section in the 1–5 MeV energy region. Those changes are well within estimated USU fission cross-section uncertainties of 1.2%, but are relevant for the evaluated mean values.
© The Authors, published by EDP Sciences, 2023
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
