弧矢压弯晶体的力学性能与形位误差分析  

Mechanical property of sagittal focusing crystal and effect of slope error on incidence angle

作　　者：凤良杰[1] 董晓浩[1] 康乐[1] 徐朝银[1] 

机构地区：[1]中国科学技术大学国家同步辐射实验室,安徽合肥230029

出　　处：《光学精密工程》2007年第3期362-367,共6页Optics and Precision Engineering

基　　金：国家自然科学基金项目(No.10575098)

摘　　要：介绍了利用柔性铰链机构对弧矢聚焦双晶单色器中第二晶体进行动态压弯的工作原理，优化了压弯机构和晶体的几何参数，然后应用有限元方法模拟分析压弯装置与晶体的力学性质，最后分析了弯晶的形位误差并计算因此造成的弯晶光束入射角的变化。分析结果表明：替换后单色器的水平接收角由1mrad增加到3mrad，样品上光斑的水平半高宽由12．5mm减小到2．5mm。优化后晶体因压弯产生的鞍形曲率半径约为弧矢曲率半径的1700倍，造成的入射角误差为2．2μrad；压弯装置上的最大平均应力约为800MPa，并由此确定了以铍青铜作为压弯机构的材料，晶体的曲率半径为0．57～1．72m和驱动力为8～2．67N时的线性关系。分析结果表明：该单色器的设计完全达到了设计指标，在提高光子通量和光子密度的同时又能满足XAFS光束线测量过程中需要频繁快速扫描的要求。The principle of dynamically bending of the crystal in a sagittal focusing monochramator by flexural hinge-based bender was presented and the geometric parameters of bender and crystal were optimized. Then the mechanical properties of bender and crystal were analyzed with Finite Element Method. Finally, the effect of slop error on the incident angle was calculated. The analyzed results indicate that the acceptance angle of the monochromator increases from 1 mrad to 3 mrad, and the horizontal width （FWHM） of the spot on the sample reduces from 12.5 mm to 2.5 mm after replacement. The anticlastic curvature caused by bending is 1 700 times as long as the sagittal curvature, and the incident angle error is only 2.2 μrad. The Von Mize stress on the bender is about 800 MPa. When Beryllium-Cu is selected as the material of the bender, the linear relationship between the curvature of crystal in 0.57-1.72 m and the driving forces in 8-2.67 N is obtained. The analyzed results also in dicate that the designing parameters are achievement in that the flux and photo intensity are increased and the requirement of fast and tunable scanning on the XAFS measurement is satisfied at the same time.

关 键 词：弧矢聚焦 双晶单色器 柔性铰链 压弯机构 形位误差 

分 类 号：TL544[核科学技术—核技术及应用]