X射线反射镜表面的功率谱密度的工作波长检测方法研究

Diffraction limited synchrotron radiations and hard x-ray free electron lasers unleash potentials of experimental techniques, such as nano-probe, coherent hard x-ray. More high performance optics is required to construct state-of-the-art beamlines, which, for instance, need reflect mirrors of less than 50nrad figure error or height waviness of not more than 1nm from peak to valley. Lack of optical metrology of ultrahigh testing sensitivity bottlenecks application and development of those high-performance mirrors, because ultrahigh sensitivity testing is greatly demanded for mirror manufacturing as well. .X-ray metrology is capable of testing precisely to much higher extent than its counterpart of visible light because of its short wavelength; and more, it may provide much information using at-wavelength testing. Features of surface slope distribution to spatial frequencies play different roles on optical characteristics of mirrors. However, to date, no effective optical metrology for mid-spatial frequency is available based on either visible light or X ray. Therefore, a goal for technical studies of measurement to mid-spatial-frequency (MSF) power spectral density (PSD) of X-ray mirrors is presented..A practicable technique of coherent small-angle X-ray scattering may bear potential for testing the profile of mirror surfaces. It will be investigated at Shanghai Synchrotron Radiation Facility, at which relationships between hard x-ray coherence and pinholes, photon energies, grazing incident angles, etc. should be researched experimentally. In comparison to theoretical simulation and visible-light testing, the methodology of testing of MSF PSD of X-ray mirrors will be completed. .The project will lead to an integrity of the surface profile PSD on the components of high-, mid-, and low-spatial frequencies. Evaluation capacity of optical characteristics of X-ray mirrors will be improved substantially. And mirror processing and coating technique will also reap instructively benefits from the investigation.

基于同步辐射衍射极限环和硬X射线自由电子激光器，将发展纳米聚焦、相干硬X射线等技术，这要求高性能的光学元件，检测技术已成为瓶颈之一。.表面斜率/高度的频率分量对反射镜性能有不同影响。目前的可见光和X射线检测技术，对中频分量仍缺乏有效的测量手段。本项目的目标是研究X射线反射镜的中频功率谱密度（PSD）测量技术（空间波长1μm~1mm），X射线的检测精度远高于可见光；此外，用工作波长检测更能反映被测镜的光学特性。.本项目的技术路线是用相干硬X射线散射测量表面高度的PSD。在上海光源发展相干X射线散射测量技术，重点研究取光小孔、X射线波长、相干度、掠入射角等因素的影响，对比理论模拟和可见光检测，形成相对完善的X射线反射镜的中频PSD检测技术。.通过项目的研究，将首次把反射镜表面的高、中、低频PSD连接起来，全面评价X射线反射镜的性能，也对超光滑面加工和镀膜工艺有重要的指导意义。

基于同步辐射衍射极限环和硬X射线自由电子激光器，将发展纳米聚焦、相干硬X射线等技术，这要求高性能的光学元件，检测技术已成为瓶颈之一。表面斜率/高度的频率分量对反射镜性能有不同影响。目前的可见光和X射线检测技术，对中频分量仍缺乏有效的测量手段。本项目建立了部分相干X射线传输理论模型，分析了同步辐射光束性质的传输过程，开展了硬X射线的相干度测量和相干衰减研究。发展了基于同步辐射的正入射和掠入射模式下的硬X 射线叠层衍射成像技术；基于上海光源波荡器光束线建立了相干散射实验平台，为国内该实验方法的发展和应用提供有效的软硬件支持；对同步辐射反射镜表面质量测量技术进行了系统研究，提出了新型的实验室中频检测技术方法。利用原位掠入射散射实验技术探究多层膜反射镜的薄膜内部结构随温度变化情况，为其在同步辐射光束线的应用提供了详细可靠的实验依据；建立硬X射线掠入射相干散射实验平台，开展了反射光学元件的表面成像实验，为同步辐射光学器件提供了全新的检测方法，全面评价高中低频误差对反射镜光学性能的影响。