Regular Article

Templates of expected measurement uncertainties for prompt fission neutron spectra

¹ Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
² CEA, DAM, DIF, F-91297 Arpajon, France
³ Univ. Bordeaux, LP2I, UMR5797, CNRS, F-33170 Gradignan, France
⁴ National Institute of Standards and Technology, Gaithersburg, MD, 20899-8463, USA
⁵ Université Paris-Saclay, CEA, LMCE, 91680 Bruyères-le-Châtel, France

^* e-mail: dneudecker@lanl.gov

Received: 24 March 2023
Received in final form: 18 July 2023
Accepted: 7 August 2023
Published online: 9 November 2023

Abstract

In this paper, we provide templates of uncertainty sources expected to appear for three measurement types of prompt fission neutron spectra (PFNS): (1) shape measurements, (2) clean-ratio shape, that is the monitor PFNS are measured in nearly exactly the same surrounding as the PFNS of interest, and (3) indirect ratios, where the detector efficiency is backed out from PFNS monitor measurements. Information is also listed that is needed to faithfully include PFNS in nuclear data evaluations to guide experimenters on how to best report data and metadata for their measurements. These templates also suggest a typical range of pertinent uncertainty values and their correlations in case realistic uncertainties cannot be estimated from information on the measurement itself. The templates were based on a literature review, information found in EXFOR for ²⁵²Cf, ^235, 238U, and ²³⁹Pu PFNS, and enhanced by expertise from experimenters contributing to these PFNS templates.