自由电子激光光束线反射镜无应力夹持设计与分析  

Design and analysis of stress-free clamping of mirrors used in free-electron laser beamlines

作　　者：赵晨行 卢启鹏[1] 宋源[1] 龚学鹏[1] 王依[1] 徐彬豪 ZHAO Chen-hang;LU Qi-peng;SONG Yuan;GONG Xue-peng;WANG Yi;XU Bin-hao(Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院长春光学精密机械与物理研究所,吉林长春130033 [2]中国科学院大学,北京100049

出　　处：《中国光学》2020年第4期787-794,共8页Chinese Optics

基　　金：国家自然科学基金(No.11079035);国家科技重大专项(No.2012ZX02702001);国家重点研发计划(2018YFD0401003-04)。

摘　　要：反射镜是自由电子激光光束线中的重要光学元件,反射镜自重引起的面形误差会严重影响光束线的成像质量。为减小自重引起的面形误差,基于Bessel点理论提出了重力补偿方案,并设计了无应力夹持装置,利用有限元软件对该装置进行仿真分析。以尺寸为440 mm×50 mm×50 mm的反射镜为例进行分析,传统支撑方式下反射镜下表面面形误差为1.647μrad,采用本文提出的夹持方案后面形误差降至0.0857μrad,优于工程指标0.1μrad。为防止反射镜在工作模式切换时发生窜动,可对反射镜添加不超过2 N的微小夹持力,此时反射镜的面形误差为0.0939μrad。此外,还对装置进行了动力学分析,结果显示:该设计方案可有效防止装置存在较低的固有频率,在使用过程中不会产生共振现象,满足光束线的使用需求。The reflector is an important optical element in free-electron laser beamlines.Deformation error caused by gravity can seriously affect the image quality of a beamline.To reduce deformation error,a gravity compensation scheme based on the Bessel point theory is proposed and a stress-free clamping device is designed.Taking a 440 mm×50 mm×50 mm mirror as an example,the analysis results indicate that the deformation error in the bottom surface of a mirror clamped with the traditional support method is 1.647μrad.Adopting the newly designed device proposed in this paper,the results of a finite element analysis showed that the deformation error reduced to 0.0857μrad,which is better than the engineering index of 0.1μrad.To prevent the mirror from moving when switching modes,a small clamping force of no more than 2 N can be added to the mirror,at which point the surface error of the mirror becomes 0.0939μrad.Additionally,a dynamic analysis of the device is also carried out,which indicates that the device mutes the low natural frequency,which means that resonance will not occur during operation.Therefore,this scheme satisfies our requirements for the beamline.

关 键 词：面形误差 无应力夹持 有限元分析 重力补偿 自由电子激光光束线 

分 类 号：TH744.1[机械工程—光学工程]