^(241)Am-Be中子源紧凑型屏蔽装置及辐照器设计

Design of Compact Shielding Device and Irradiator Based on^(241)Am-Be Neutron Source

^(241)Am-Be中子源被广泛用于实验研究,为保护实验人员免受中子及γ射线照射,需要设计适当的屏蔽。利用蒙特卡罗方法计算中子透射不同材料后的能谱分布与剂量,优选各层屏蔽材料种类与厚度,设计一套^(241)Am-Be中子源紧凑型屏蔽装置。装置由内而外采用钨+聚乙烯+含硼聚乙烯+不锈钢进行防护,外表面周围剂量当量率H^(*)(10)低于10μSv/h,满足辐射防护要求。同时对装置内部热中子、超热中子和快中子注量分布进行研究,确定装置快中子和热中子输出通道最佳位置。在辐照装置同时开放快中子和热中子通道进行实验测试时,需要设置距离大于130 cm的控制区,以保障操作人员安全。

The^(241)Am-Be neutron source is widely used in experimental research.Proper shielding needs to be designed to protect experimenters from neutron and gamma radiation.The energy spectrum distribution and dose value of neutrons transmitted through different materials were calculated by the Monte Carlo method to optimize the type and thickness of each layer of shielding material.A compact shielding device for^(241)Am-Be neutron source is designed.The device protection adopts a four-layer combination of tungsten+polyethylene+borated polyethylene+stainless steel.The dose equivalent rate H^(*)(10)around the outer surface is lower than 10μSv/h,which meets the radiation protection requirements.The fluence distribution of thermal neutron,epithermal neutron and fast neutron in the device is studied to determine the best opening position of the fast neutron and thermal neutron output channel of this device.When the irradiation device simultaneously opens the fast neutron and thermal neutron channels for experimental testing,it is necessary to set up a control area with a distance greater than 130 cm to ensure the safety of the worker.