计算了11 MeV 正电子发射成像回旋加速器18O(p,n)18F反应的双微分截面数据，并采用蒙特卡罗模拟计算方法，分析了单一材料及复合结构对特定辐射源的防护性能。采用单一材料，质量分数为73.8%的重混凝土的防护效果最佳，经过90 cm厚屏蔽层的衰减，距离辐射源正前方1 m处的总剂量降低约5个量级；复合结构采用多层结构，材料选用铁及硼酸溶液，同样厚度即可达到与重混凝土相同的防护效果，密度可降低至少20%。

An 11 MeV cyclotron used for production of positron emission radionuclide aiming at positron emission tomography (PET) imaging produces a huge quantity of instant neutron and gamma ray radiation. For shielding this kind of accelerator, a self-shielding bunker-like structure is employed, which can be designed with Monte Carlo method. The discrete dual-differential section data are calculated first to obtain the input data for Monte Carlo code, with which the protection characteristics with a single layer and composite structure of various materials are simulated next. The results show that with a single layer, the heavy concrete which has 73.8% iron content brings greatest protection characteristic among all of the materials included in this paper and attenuates the total dose rate about 100 kilo times at the position of 1 m far away from the radiation source with 0° emission angle with thickness of 90 cm. With materials of iron and boracic acid liquor, a particular composite structure can bring the same characteristic with the same thickness and reduce the total density about 20% at least.