Westcott $g$ Factors Extended to Arbitrary Neutron Energy Spectra
Abstract
Westcott factors are used in Neutron Activation Analysis (NAA) and Prompt Gamma-ray Activation Analysis (PGAA) to evaluate the impact of non- behavior in the neutron-capture cross sections of certain nuclei on activation product yields. This non- behavior arises from the presence of neutron resonances in the neutron-capture cross sections that overlap with the source neutron spectrum at low (~eV) energies. Historically, Westcott factors that have been cataloged for NAA and PGAA applications are the result of calculations that assume a Maxwellian neutron velocity distribution with a given average temperature. In this study, we use this approach with updated neutron-capture cross sections from the Evaluated Nuclear Data File, version VIII.1 (ENDF/B-VIII.1) to tabulate Westcott factor values for a broad range of Maxwellian distribution temperatures, comparing the results against currently-available factors from International Atomic Energy Agency tables and other sources. It was discovered during this analysis that the use of guided thermal and cold-neutron beams at certain facilities necessitates an approach for evaluating Westcott factors based on arbitrary non-Maxwellian spectra. In this paper, we present an approach for calculating factors with user-specified neutron spectra, and we apply these methods to obtain Westcott -factors for guided- and cold-neutron beams at the Budapest Research Reactor and the Forschungsreaktor M{\"u}nchen II reactor. Open-source software has been developed as part of this study that can be used to perform these calculations for applications in PGAA and NAA experiments
Keywords
Cite
@article{arxiv.2602.05995,
title = {Westcott $g$ Factors Extended to Arbitrary Neutron Energy Spectra},
author = {D. A. Matters and A. M. Hurst and T. Kawano},
journal= {arXiv preprint arXiv:2602.05995},
year = {2026}
}