中文摘要：

目的设计用于硼中子俘获治疗（BNCT）的超热中子柬理论方案。方法基于清华大学试验核反应堆，以其1号孔道为材料布放孔道，设计了由慢化材料、热中子吸收材料、1屏蔽材料组成，但材料布放位置具有差异的5种理论方案；利用蒙特卡罗（MC）模拟方法，分别计算5种方案柬出口处的中子注量率、剂量率及γ剂量率值，通过与BNCT技术指标对比，从5种方案中选择一种合适的方案。结果得到了一个符合BNCT各项技术指标的超热中子束理论方案，其慢化材料厚度为53．5cm、热中子吸收材料厚度为2mm、γ屏蔽材料厚度为9cm。结论本研究给出的超热中子束理论方案为基于反应堆实现BNCT提供一定的理论参考。

英文摘要：

Objective To design a scheme of epithermal neutron beam used for boron neutron capture therapy （BNCT）. Methods Based on Tsinghua University experimental reactor and its No. 1 passage, five schemes comprised of moderate materials, absorbing materials of thermal neutron and γ shielding materials were designed according to different locations of materials placed in No. 1 passage. To select a proper scheme from five schemes, the neutron fluence rate, the neutron dose rate and γ dose rate at exit of beam in each scheme were calculated with Monte Carlo simulating methods and then contrasted with BNCT technique criterion. Results The scheme of epithermal neutron beam meeting technical requirements of BNCT was obtained, in which the thickness of moderate material, absorbing materials of thermal neutron and γ shielding materials are 53.5 cm, 2 mm and 9 cm, respectively. Conclusions The theoretical scheme could provide some reference to realize BNCT on reactor.