【作者】 刘山；

【导师】 丁学勇； 薛向欣；

【作者基本信息】 东北大学 ， 冶金工程（专业学位）， 2018， 硕士

【摘要】 近年来随着射线装置和核技术应用的进一步发展,传统、单一的屏蔽材料越来越不能满足现代防护设备的要求。铅等传统材料一直比较昂贵,且铅有毒,因此研究成本低廉、屏蔽性能良好且无毒环保的新型屏蔽材料越来越成为一项有意义的课题方向。热镀锌渣中的锌含量丰富,而很多含锌屏蔽材料相关的研究证明锌元素的γ射线屏蔽性能较好,又锌渣价廉易取、来源广泛且无毒无害,因此热镀锌渣制备的γ射线屏蔽材料很大可能上具有较好的应用潜力。本文以热镀锌渣为研究对象开展研究工作,具体内容如下:1.在镀锌渣可行性模拟过程中,用WinXCOM软件分别从质量衰减系数、半值层厚度、平均自由程、有效原子序数及电子密度五个方面对镀锌渣进行模拟分析,并一一与目前常用γ射线屏蔽材料(铅、铁、混凝土和水)进行对比,得到热镀锌渣的屏蔽效果与铁很接近,且锌渣与混凝土、水相比具有较大的优势。模拟结果是:热镀锌渣的γ射线屏蔽性能较好,理论上具备制备屏蔽材料的可能性。2.γ射线屏蔽测试结果表明:制备的镀锌渣材料具有一定的屏蔽能力。当厚度选取为0.5、1.0、1.5、2.0 cm时,不同组分镀锌渣的屏蔽率范围为20.69%～63.37%。当厚度一定时,Zn元素含量越高,镀锌渣屏蔽材料的密度越大,其屏蔽率越高;当组分一定时,镀锌渣屏蔽材料的厚度越大,其屏蔽率也越高。WinXCOM软件模拟计算相同实验测试条件下的质量衰减系数理论值与实验值的相对误差在3.17%～12.93%的范围内,表明它们具有很好的一致性。3.镀锌渣屏蔽过程的机理分析表明:在1keV～0.2MeV的低能量阶段,光电效应是产生屏蔽效果的主要作用形式;0.2MeV～10MeV的中等能量阶段,康普顿散射则起到了主要屏蔽作用;在10MeV～100GeV高能量阶段,电子对效应则是材料与光子的主要作用形式。其中在1keV～0.2MeV能量时,光电效应对能量的变化非常敏感,其总质量衰减系数随光子能量的增加而快速衰减,且在1.31、1.56、1.84、2.472、4.04、7.11、9.66keV能量处质量衰减系数突变增加。这些能量分别对应Mg、Al、Si、S、Ca、Fe和Zn元素的K层特征吸收限能量,其中9.66keV能量处突变增加程度最大,因为其对应的Zn元素在镀锌渣中含量最高。更多还原

【Abstract】 With the further development of the applications of radiographic devices and nuclear technology in recent years,traditional and single shielding materials are becoming more and more unable to meet the requirements of modern protective equipment.Traditional materials such as lead have been very expensive and lead is poisonous,so the research of new shielding materials with low cost,good shielding performance and non-toxic environmental protection has become a more and more meaningful topic.The related studies have proved that the gamma ray shielding performance of zinc element is good,meanwhile the content of zinc in hot galvanizing slag is rich.Also,hot galvanizing slag is a kind of cheap,easy to take,non-toxic and abundant source.Therefore,the gamma-ray shielding materials prepared by hot dip galvanizing slag are likely to have good application potential.In this paper,hot galvanizing slag is taken as the research object,and the specific contents are as follows.1.In the process of feasibility simulation of galvanized slag,WinXCOM software is used to simulate and analyze hot galvanizing slag from five aspects:mass attenuation coefficient,half-value layer,mean free path,effective atomic number and electron density.What’s more,it was compared with the common gamma ray shielding materials(like lead,iron,concrete and water).The result shows that the shielding ability of hot galvanizing slag is close to iron but much better than concrete and water.In other word,hot galvanizing slag has a good shielding performance exposed to gamma ray,so it could be used to make shielding materials theoretically.2.The results of gamma ray shielding test show that the preparation of galvanized slag material has a certain degree of shielding ability.When the thickness was selected as 0.5,1.0,1.5,2.0 cm,the shielding rate of the galvanized slag in different components was 20.69%-63.37%.Besides,when the thickness is certain,the higher the Zn element content,the higher the density of the galvanized slag shielding material and the higher the shielding rate.When the components are certain,the higher the thickness of the galvanized slag shielding material,the higher the shielding rate.The relative error between the experimental values and theoretical value of the mass attenuation coefficients,which is simulated under the same experimental conditions,are in the range of 3.17%～12.93%.Therefore,it indicates that they are of good consistency.3.The mechanism analysis of galvanized slag shielding process shows that photoelectric effect is the main form of shielding effect in the low energy range of 1keV～0.2 MeV.In the medium energy range of 0.2MeV～lOMeV,Compton scattering plays the main shielding role.And electron pair effect is the main action form between the material and photons during the 5MeV～100GeV high energy range.In the range of 1keV～0.2MeV energy,the photoelectric effect is very sensitive to the change of energy and its total mass attenuation coefficient decreases rapidly with the increase of photon energy.Moreover,the mass attenuation coefficient of hot dip galvanizing slag increase dramatically in 1.31,1.56,1.84,2.472,4.04,7.11,9.66keV energy.These energies are corresponded to the K-layer characteristics absorption limit energy of Mg,Al,Si,S,Ca,Fe,and Zn element respectively.What’s more,the 9.66keV energy has the largest mutation increase for there is highest content of corresponding Zn element in the galvanized slag.更多还原