基于D-Be紧凑型快中子源的中子慢化整形器研究

[Background]: Boron Neutron Capture Therapy (BNCT) is a binary radiation therapy with strong targeting and high energy transfer line density at the cellular scale.It has the advantages of short treatment cycle and minimal damage to surrounding healthy tissues,making it a promising cancer treatment method. [Purpose]: This study aims to design beam shaping assembly(BSA)to make the neutron beam of D-Be neutron source suitable for BNCT and ensure neutron directionality. [Methods]: This article uses Monte Carlo simulation programs GEANT4 and FLUKA to simulate the generation of 9Be(d, n)10B reaction neutron sources and subsequent neutron moderation.A scheme design for BSA was carried out using a 1.45 MeV,30 mA deuterium beam to bombard a 9 μm thin beryllium target,and set a basis BSA model with a cylindrical structure as a whole. [Results]: The results show that using a 20 cm thick BiF3 and 30 cm thick MgF2 combined slowing layer, a 30 cm thick Pb reflector layer, a 9 cm thick MgF2 supplementary slowing layer, and a 0.2 mm thick Cd thermal neutron absorption layer,the outlet is ensured to γ and fast neutron composition,Φepi/Φth, Φepi/Φfast meets the recommended values of the IAEA. [Conclusions]: This study obtained the neutron spectra and BSA specific design scheme of low-energy deuterium beams and thin beryllium targets,providing data reference for the slowing shaping of neutrons in D-Be neutron sources and supporting subsequent research on D-Be sources.

[背景]: 硼中子俘获治疗（Boron Neutron Capture Therapy, BNCT）是一种二元放射治疗技术，具备靶向性强、细胞尺度下能量传递线密度高的特点。其具有治疗周期短、对周围健康组织损伤极小的优势，是极具潜力的癌症治疗手段。
[目的]: 本研究旨在设计束流整形组件（Beam Shaping Assembly, BSA），使D-Be中子源的中子束适配硼中子俘获治疗需求，并保证中子的方向性。
[方法]: 本文采用蒙特卡罗模拟程序GEANT4与FLUKA，对9Be(d, n)10B反应中子源的产生及后续中子慢化过程开展模拟；以1.45 MeV、30 mA的氘束轰击9 μm厚的薄铍靶，开展束流整形组件的方案设计，并构建整体为圆柱结构的基础束流整形组件模型。
[结果]: 结果表明，采用20 cm厚的三氟化铋（BiF3）与30 cm厚的氟化镁（MgF2）组成的复合慢化层、30 cm厚的铅（Pb）反射层、9 cm厚的氟化镁辅助慢化层，以及0.2 mm厚的镉（Cd）热中子吸收层时，出口中子束的γ射线与快中子组分、超热中子与热中子通量比（Φepi/Φth）、超热中子与快中子通量比（Φepi/Φfast）均符合国际原子能机构（International Atomic Energy Agency, IAEA）的推荐值。
[结论]: 本研究获得了低能氘束与薄铍靶对应的中子能谱及束流整形组件的专属设计方案，可为D-Be中子源的中子慢化整形提供数据参考，并为后续D-Be源相关研究提供支撑。