Design of a neutron target for boron neutron capture therapy

Abstract

BackgroundBoron neutron capture therapy (BNCT) is a promising tumor therapy method that irradiates 10B attached tumors with thermal or epithermal neutrons. Specifically, 7Li(p,n)7Be is one of the main methods for producing thermal or epithermal neutrons. The Li target is a critical component for BNCT device.PurposeThis study aims to design a composite material Li target with a semi-tirelike surface structure that rotates around a central axis.MethodsBased on a 2.5 MeV, 20 mA proton beam, the TOPAS Monte Carlo software was used to simulate the influence of curved lithium target with different radial axial ratios on the angular distribution, energy spectrum, and flux of neutrons. The steady-state temperature distribution of the neutron target was simulated by using ANSYS software to investigate the impact of radial axial ratios on heat dissipation.ResultsThe simulated results show that the semi-tirelike curved surface enhances the concentration of the output neutron beam. When the radial axis ratio is 1.5, the number of neutrons with an exit angle of 0°~45° is 2.59 times that of the same plane target whereas the number of neutrons with an exit angle of greater than 90° is only 0.29 times that of a planar target in the same situation. The heat dissipation performance is improved by the fold channel design and curved surface structure. The maximum temperature of the lithium layer is only 100 ℃ for a 50-kW proton beam incident, which satisfies the heat dissipation requirement.ConclusionThe innovative curved neutron target of this study significantly improves the forward performance of the outgoing neutron and heat dissipation performance when compared with the conventional plane target. These types of advancements will lead to good prospects in the field of BNCT.

Keywords

• boron neutron capture therapy
• neutron target
• monte carlo simulation