Yashchuk Valeriy V, Lacey Ian, Gevorkyan Gevork S, McKinney Wayne R, Smith Brian V, Warwick Tony
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Rev Sci Instrum. 2019 Feb;90(2):021711. doi: 10.1063/1.5057441.
Super high quality aspherical x-ray mirrors with a residual slope error of ∼100 nrad (root-mean-square) and a height error of ∼1-2 nm (peak-to-valley), and even lower, are now available from a number of the most advanced vendors utilizing deterministic polishing techniques. The mirror specification for the fabrication is based on the simulations of the desired performance of the mirror in the beamline optical system and is normally given with the acceptable level of deviation of the mirror figure and finish from the desired ideal shape. For example, in the case of aspherical x-ray mirrors designed for the Advanced Light Source (ALS) QERLIN beamline, the ideal shape is defined with the beamline application (conjugate) parameters and their tolerances. In this paper, we first discuss an original procedure and dedicated software developed at the ALS X-Ray Optics Laboratory (XROL) for optimization of beamline performance of pre-shaped hyperbolic and elliptical mirrors. The optimization is based on results of ex situ surface slope metrology and consists in minimization of the mirror shape error by determining the conjugate parameters of the best-fit ideal shape within the specified tolerances. We describe novel optical metrology instrumentation, measuring techniques, and analytical methods used at the XROL for acquisition of surface slope data and optimization of the optic's beamline performance. The high efficacy of the developed experimental methods and data analysis procedures is demonstrated in results of measurements with and performance optimization of hyperbolic and elliptical cylinder mirrors designed and fabricated for the ALS QERLIN beamline.
现在，一些最先进的供应商利用确定性抛光技术，能够提供超高质量的非球面X射线镜，其残余斜率误差约为100纳弧度（均方根），高度误差约为1 - 2纳米（峰谷值），甚至更低。制造镜子的规格是基于对光束线光学系统中镜子所需性能的模拟，通常会给出镜子外形和光洁度与所需理想形状的可接受偏差水平。例如，对于为先进光源（ALS）的QERLIN光束线设计的非球面X射线镜，理想形状是根据光束线应用（共轭）参数及其公差来定义的。在本文中，我们首先讨论了美国劳伦斯伯克利国家实验室X射线光学实验室（XROL）开发的一种原始程序和专用软件，用于优化预成型双曲线和椭圆镜的光束线性能。这种优化基于非原位表面斜率计量的结果，包括通过在指定公差范围内确定最佳拟合理想形状的共轭参数来最小化镜子形状误差。我们描述了XROL用于获取表面斜率数据和优化光学元件光束线性能的新型光学计量仪器、测量技术和分析方法。为ALS的QERLIN光束线设计和制造的双曲线和椭圆柱面镜的测量结果和性能优化，证明了所开发的实验方法和数据分析程序的高效性。
