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Main Authors: Hauksson, Sigtryggur, Casalbore, Ilaria, Tomatis, Daniele, Burgio, Nunzio
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2510.22382
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author Hauksson, Sigtryggur
Casalbore, Ilaria
Tomatis, Daniele
Burgio, Nunzio
author_facet Hauksson, Sigtryggur
Casalbore, Ilaria
Tomatis, Daniele
Burgio, Nunzio
contents Quantifying inherent neutron sources in matter, particularly $(α, n)$ reactions and spontaneous fission, is important in nuclear engineering and other fields. The SOURCES code is a common tool for calculating the yield and spectrum of such neutrons. This paper critically examines all modelling assumptions and nuclear data in SOURCES and proposes alternative approaches where applicable. For $(α, n)$ reactions, we show that the alpha emission lines for $^{235}\mathrm{U}$ should be updated. Furthermore, we compare four different stopping power data sets for alpha particles slowing down and propose measurements to constrain mixed oxide nuclear fuel data. We use the computer code PHITS to show that energy and angular straggling during the slowing down of alpha particles in the material of interest is unimportant. Then, we compare the cross section and emission spectrum of $(α, n)$ reactions in SOURCES to recently evaluated data libraries. Importantly, the modelling of SOURCES for the emission spectrum seems too simple and may need to be updated. Finally, we compare data on spontaneous fission and show that while the neutron yield from SOURCES is reliable, some discrepancy is found with the neutron spectrum of evaluated data libraries. Complementing this work is an implementation of spontaneous fission in the Monte Carlo code OpenMC.
format Preprint
id arxiv_https___arxiv_org_abs_2510_22382
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Investigation of evaluated nuclear data in the prediction of inherent neutron sources
Hauksson, Sigtryggur
Casalbore, Ilaria
Tomatis, Daniele
Burgio, Nunzio
Nuclear Theory
Quantifying inherent neutron sources in matter, particularly $(α, n)$ reactions and spontaneous fission, is important in nuclear engineering and other fields. The SOURCES code is a common tool for calculating the yield and spectrum of such neutrons. This paper critically examines all modelling assumptions and nuclear data in SOURCES and proposes alternative approaches where applicable. For $(α, n)$ reactions, we show that the alpha emission lines for $^{235}\mathrm{U}$ should be updated. Furthermore, we compare four different stopping power data sets for alpha particles slowing down and propose measurements to constrain mixed oxide nuclear fuel data. We use the computer code PHITS to show that energy and angular straggling during the slowing down of alpha particles in the material of interest is unimportant. Then, we compare the cross section and emission spectrum of $(α, n)$ reactions in SOURCES to recently evaluated data libraries. Importantly, the modelling of SOURCES for the emission spectrum seems too simple and may need to be updated. Finally, we compare data on spontaneous fission and show that while the neutron yield from SOURCES is reliable, some discrepancy is found with the neutron spectrum of evaluated data libraries. Complementing this work is an implementation of spontaneous fission in the Monte Carlo code OpenMC.
title Investigation of evaluated nuclear data in the prediction of inherent neutron sources
topic Nuclear Theory
url https://arxiv.org/abs/2510.22382