中文摘要：

双晶单色器是同步辐射光源光束线上的关键设备之一，其通过内部的第一晶体与第二晶体获得实验所需的单一波长的谱线，故晶体的装配安装直接影响实验站同步辐射光的品质。通过实验测试结合有限元分析的方法，建立单色器第一晶体在一定的螺栓紧固力下的有限元分析模型，验证模型的有效性，进而分析晶体的面形精度、安装机构的应力分布、“〇”圈的形变等指标，研究安装过程中一晶及其安装机构的受力情况与力学响应，为高面形精度晶体的安装提供指导与借鉴。

英文摘要：

Background： The double crystal monochromator is one of the key equipments on the beamline of synchrotron radiation light source. It obtains the required single wavelength light using the first crystal and the second crystal, thus the assembly and installation of the crystals directly affect the quality of synchrotron radiation. Purpose： The aim is to introduce the proposed method of finite element analysis （FEA）, as well as providing useful guidance and reference for the high-precision installation of crystal with high surface quality. Methods： The simplified finite element model of the first crystal assembly subjected to a certain bolt fastening force is established. By validating the effectiveness of the model, as well as analyzing the slope error of crystal, the stress distribution of the installation parts and the deformation of the ＂O＂ ring, to study the mechanical response and mechanism of crystal and its mounting assembly during installation process. Results： It is found that the experimental result shows good agreement with FEA result, which proves the accuracy of the presented finite element model. For the phenomenon of stress concentration of various parts and deformation of ＂O＂ ring, all of which locate in the allowable range. Conclusion： The installation indicators of first crystal assembly meet the engineering requirements. And the proposed effective FEA technique is expected to be used for the mechanical properties analysis of synchrotron radiation facilities.