ALPHANSO: Open-Source Modeling of ($\alpha$,n) Neutron Source Terms

TL;DR

ALPHANSO is an open-source Python tool that accurately predicts neutron yields and spectra from ($ extalpha$,n) reactions, improving upon legacy software with modern data and modular design.

Contribution

It introduces ALPHANSO, a modern, open-source, and modular Python package for calculating ($ extalpha$,n) neutron source terms with updated nuclear data.

Findings

ALPHANSO accurately reproduces neutron yields and spectra compared to experimental data.

It shows good agreement with existing tools like SOURCES-4A and NeuCBOT.

ALPHANSO is reliable, accessible, and easily extensible for future data updates.

Abstract

Applications ranging from nuclear safeguards to dark matter detection require accurate predictions of neutron yields and energy spectra produced by ($\alpha$,n) reactions. Legacy tools like SOURCES-4C remain widely used despite significant limitations, including outdated nuclear data, missing target nuclides, and restricted accessibility. Here, we present ALPHANSO, an open-source Python package for calculating ($\alpha$,n) neutron source terms. ALPHANSO incorporates modern nuclear data libraries and formats covering all naturally occurring target nuclides and provides a transparent, modular framework for updating or extending the data as new evaluations are released. Comparison with an updated version of SOURCES-4A, NeuCBOT, and experimental measurements across a range of elements and materials shows that ALPHANSO reproduces neutron yields and spectra in good agreement with experimental data and state-of-the-art ($\alpha$,n) calculations. These results demonstrate that ALPHANSO is a reliable, accessible, and modern alternative to legacy ($\alpha$,n) source term codes such as SOURCES-4C. Its open-source design and modular data handling make it readily extensible to future evaluated nuclear data and low-background applications.