Jardin, D.
, Díaz-Comeche, A.
, Oliver, S.
, Juste, B.
, Zakhary, M.
, Mossahebi, S.
, Mille, M.
, Lee, C.
, Miró, R.
, Verdú, G.
and Morató, S.
(2026),
Monte Carlo simulation and unfolding of an extended Bonner sphere system for secondary neutron spectrometry in proton therapy facilities using conventional BSS experimental data, Frontiers in Oncology, [online], https://doi.org/10.3389/fonc.2026.1789835, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=961312 (Accessed June 11, 2026)
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Monte Carlo simulation and unfolding of an extended Bonner sphere system for secondary neutron spectrometry in proton therapy facilities using conventional BSS experimental data
Published
Author(s)
, Adrián Díaz-Comeche, Sandra Oliver, Belén Juste, Mark Zakhary, Sina Mossahebi, Matthew Mille, Choonsik Lee, Rafael Miró, Gumersindo Verdú, Sergio Morató
Abstract
The extended-range Bonner Sphere Spectrometer (BSS) is a valuable tool for characterizing neutron fields in radiotherapy, including proton therapy facilities, where secondary neutrons contribute to the incidental dose received by the patient and staff. In this study we developed and validated a Monte Carlo (MC) model of an extended-range BSS by benchmarking against experimental measurements performed using a conventional BSS in a proton therapy facility. The extended-range system, which includes four additional spheres with aluminum and lead layers, was not available for this work; instead, simulations were validated against conventional BSS data and then applied to extrapolate the high-energy portion of the neutron spectrum. The MC simulations were performed using MCNP version 6.3 and include modelling of the BSS and using BSS response functions previously validated. The comparison in data trends between simulations and measurements confirms the reliability of the simulation model. The acquired neutron spectra show the characteristic shape, but also noticeable differences between the measurement locations in the intensity and width of the direct, evaporation, and thermal peaks. These differences are consistent with the changing measurement conditions in each case. The obtained spectra show similarity with other spectra available in literature. This work demonstrates that MC-modeled extended-range BSS can accurately characterize secondary neutron spectra in proton therapy facilities, providing a foundation for improved radiation protection and dose optimization studies.The MC simulations were performed using MCNP6.3 code and included modelling of the BSS and using BSS response functions previously validated. The comparison in data trends between simulations and measurements confirms the reliability of the simulation model. The acquired neutron spectra show the characteristic shape, but also noticeable differences between the measurement points with regard to the intensity and thickness of the direct, evaporation, and thermal peaks. These differences are consistent with the changing measurement conditions in each case. The obtained spectra show similarity with other spectra available in literature. This work demonstrates that MC-modeled extended-range BSS can accurately characterize secondary neutron spectra in proton therapy facilities, providing a foundation for improved radiation protection and dose optimization studies.Citation
Frontiers in Oncology
Volume
16
Pub Type
Journals
Download Paper
Keywords
Proton therapy, neutron spectrometry, Monte Carlo
Citation
Issues
If you have any questions about this publication or are having problems accessing it, please contact [email protected].
Created April 12, 2026, Updated June 8, 2026