Super precision Metrology for Synchrotron X-ray mirrors

同步辐射X射线反射镜的超精密测量项目目标该项目属于EPSRC工程研究领域，旨在开发一种基于散斑计量技术的新型超精密计量技术。描述同步辐射装置，如金刚石光源，可以被认为是一个巨大的显微镜，提供连贯和非常明亮的X射线辐射束，科学家可以用来研究从化石到喷气发动机到病毒和疫苗的任何东西。反过来，这种光束的成功利用要求光学元件以非常高的公差制造。下一代衍射极限储存环对高精度光学和计量技术的要求将更加严格，目前基于实验室的X射线反射镜计量技术的精度仅限于~50 - 100nrad。为了进一步提高高质量X射线反射镜的光束性能，迫切需要发展超精密测量技术。X射线波前传感技术能够以超高精度精确测量波前和相关像差。（Sawhney等人，2013年）。近年来，基于X射线散斑的技术在金刚石光源的原位镜面测量中得到了广泛的发展和深入的研究。(Wang在该项目中，该技术将从X射线扩展到可见光范围。本文针对精密计量用X射线反射镜进行了散斑计量仪的光学设计、计算机模拟和实验实现。在可见光范围内实施基于散斑的计量技术有可能获得具有前所未有的精度低至20 nrad的X射线反射镜的斜率误差分布，这将是同类计量工具中的第一个，并使X射线光学器件的制造商和用户受益。它还将允许一个更便宜和更通用的替代品来表征X射线光学镜的其他现有技术。该项目是在牛津大学和钻石光源有限公司之间的合作下进行的。等人（2013）"金刚石光源处的X射线光学的At波长计量"，Synchrotron Radiation News，26（5），第17 - 22. Wang，H.，Kashyap，Y.和Sawhney，K.（2015）“具有纳米角灵敏度的基于散斑的X射线波前传感”，Optics Express，23（18），第23310页。

Super precision Metrology for Synchrotron X-ray mirrorsProject AimsThis project falls within the EPSRC Engineering research area and aims to develop a novel super-precision metrology based on a speckle based metrology technique.DescriptionA synchrotron radiation facility, such as Diamond Light Source, can be considered as a giant microscope, providing coherent and extremely bright X-ray radiation beams that scientists can use to study anything from fossils to jet engines to viruses and vaccines. In turn, the successful exploitation of such beams requires optical elements to be manufactured to very high tolerances. The requirement for high precision optics and metrology will be even more demanding for the next generation diffraction-limited storage rings.The present state-of-the-art lab-based metrology techniques for X-ray mirrors are limited to a precision of ~50-100nrad. To further improve the beam performance with high quality X-ray mirrors, there is an urgent demand to develop a super precision metrology technique. X-ray wavefront sensing techniques are able to precisely measure the wavefront and the associated aberrations with ultra-high accuracy. (Sawhney et al., 2013). Recently, the X-ray speckle based technique has been extensively developed and intensively studied for in-situ mirror metrology at Diamond Light Source. (Wang, Kashyap and Sawhney, 2015)In the project, the technique will be extended from X-rays to the visible light regime. The optical design, computer simulation and experimental implementation of the speckle-based metrology instrument will be carried out for the precision metrology X-ray mirrors. Implementing the speckle-based metrology technique in the visible light regime has the potential to obtain slope error profiles of X-ray mirrors with unprecedented precisions down to 20 nrad, It would be the first of its kind metrology tool and benefit the manufacturers and users of X-ray optics alike. It will also allow a cheaper and more versatile alternative to characterize x-ray optics mirrors to the other existing techniques This project is under collaboration between the University of Oxford and Diamond Light Source ltd.ReferencesSawhney, K. et al. (2013) 'At-wavelength Metrology of X-ray Optics at Diamond Light Source', Synchrotron Radiation News, 26(5), pp. 17-22.Wang, H., Kashyap, Y. and Sawhney, K. (2015) 'Speckle based X-ray wavefront sensing with nanoradian angular sensitivity', Optics Express, 23(18), p. 23310.