AB019. Design study of real-time absolute epi-thermal neutron flux intensity monitor using scintillation detectors
Abstract

AB019. Design study of real-time absolute epi-thermal neutron flux intensity monitor using scintillation detectors

Jiye Qiu, Daisuke Hatano, Shingo Tamaki, Sachie Kusaka, Isao Murata

Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University, Osaka, Japan

Correspondence to: Isao Murata, PhD. Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka 565-0871, Japan. Email: murata@see.eng.osaka-u.ac.jp.

Background: In boron neutron capture therapy (BNCT), epi-thermal neutron irradiation is carried out to treat deep-seated cancers, as epi-thermal neutrons can be slowed down in a human body and converted into thermal neutrons before reaching the tumor. Since the number of irradiated epi-thermal neutrons determines the therapeutic effect, it is significantly required to measure the absolute epi-thermal neutron intensity during the irradiation. Thus, we have been developing a novel monitor to measure the absolute epi-thermal neutron flux intensity on the body surface of a patient in real-time during BNCT treatment.

Methods: In this study, the monitor was designed by combining multiple detectors, and each detector was designed setting neutron absorbers in front of the scintillator, to make the response constant to epi-thermal neutrons, and simultaneously to reduce the response to thermal and fast neutrons. Lithium calcium aluminum fluoride (LiCAF) crystal scintillator based on 6Li(n, α)3H reaction, and EJ-254 plastic scintillator based on 10B(n, α)7Li reaction, were considered as potential neutron detection scintillator. We calculated the neutron responses of the two monitors by PHITS code, changing covered absorbers thicknesses. Finally, the neutron responses were evaluated by the reaction rates inside the scintillators.

Results: Both designed monitors successfully have a constant reaction rate in epi-thermal energy range, by combining the responses of three scintillation detectors covered by boron absorbers with different thicknesses.

Conclusions: We designed neutron monitors with LiCAF and EJ-254 scintillators, that have minimized response to thermal and fast neutron energy regions, and flat response in epi-thermal energy region with an uncertainty around 5%. In the future, we will carry out experiments to evaluate the performance of designed monitors with LiCAF and EJ-254.

Keywords: Boron neutron capture therapy (BNCT); epi-thermal neutrons; radiation detection; scintillators; neutron flux measurement

Acknowledgments

None.

Footnote

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tro.amegroups.com/article/view/10.21037/tro-25-ab019/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. Since this study involved only computational modeling and technical device development without human or animal subjects, formal ethical approval was not required.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the noncommercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

doi: 10.21037/tro-25-ab019
Cite this abstract as: Qiu J, Hatano D, Tamaki S, Kusaka S, Murata I. AB019. Design study of real-time absolute epi-thermal neutron flux intensity monitor using scintillation detectors. Ther Radiol Oncol 2025;9:AB019.

Article Options

Download Citation

Share