硼中子俘获治疗中子靶设计  

Design of a neutron target for boron neutron capture therapy

作　　者：王君岩 孔海云 李德明[1] WANG Junyan;KONG Haiyun;LI Deming(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院上海应用物理研究所,上海201800 [2]中国科学院大学,北京100049

出　　处：《核技术》2024年第4期32-38,共7页Nuclear Techniques

基　　金：科技部国家重点研发计划项目(No.2016YFC0105401)资助。

摘　　要：锂靶是^(7)Li(p,n)^(7)Be型硼中子俘获治疗装置中的关键部件。为设计一种可绕中心轴旋转的半轮胎状曲面结构的复合材料Li靶,采用蒙特卡罗工具包TOPAS模拟2.5 MeV、20 mA质子束入射不同径轴比的曲面锂靶对出射中子角分布、能谱和通量的影响,采用ANSYS模拟了该靶的稳态温度分布。模拟结果表明:半轮胎状曲面结构的设计使得出射中子束更加集中,当径轴比为1.5时,出射角为0°~45°的中子数为相同情况平面靶的2.59倍,大于90°的中子数仅为相同情况平面靶的0.29倍。该曲面结构和褶皱水道设计使其散热性能也更优,对于50 kW的入射质子束,锂层稳态最高温度仅100℃,满足其散热要求。该新型曲面中子靶相比于传统平面靶极大地提升了出射中子的前向性和散热性能,在硼中子俘获治疗领域具有良好的应用前景。[Background]Boron neutron capture therapy(BNCT)is a promising tumor therapy method that irradiates 10B attached tumors with thermal or epithermal neutrons.Specifically,^(7)Li(p,n)^(7)Be is one of the main methods for producing thermal or epithermal neutrons.The Li target is a critical component for BNCT device.[Purpose]This study aims to design a composite material Li target with a semi-tirelike surface structure that rotates around a central axis.[Methods]Based 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.[Results]The 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.[Conclusion]The 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.

关 键 词：硼中子俘获治疗 中子靶 蒙特卡罗模拟 

分 类 号：TL99[核科学技术—核技术及应用]