Goldberg Kenneth A, Wojdyla Antoine, Bryant Diane
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Sensors (Basel). 2021 Jan 13;21(2):536. doi: 10.3390/s21020536.
New, high-coherent-flux X-ray beamlines at synchrotron and free-electron laser light sources rely on wavefront sensors to achieve and maintain optimal alignment under dynamic operating conditions. This includes feedback to adaptive X-ray optics. We describe the design and modeling of a new class of binary-amplitude reflective gratings for shearing interferometry and Hartmann wavefront sensing. Compact arrays of deeply etched gratings illuminated at glancing incidence can withstand higher power densities than transmission membranes and can be designed to operate across a broad range of photon energies with a fixed grating-to-detector distance. Coherent wave-propagation is used to study the energy bandwidth of individual elements in an array and to set the design parameters. We observe that shearing operates well over a ±10% bandwidth, while Hartmann can be extended to ±30% or more, in our configuration. We apply this methodology to the design of a wavefront sensor for a soft X-ray beamline operating from 230 eV to 1400 eV and model shearing and Hartmann tests in the presence of varying wavefront aberration types and magnitudes.
同步加速器和自由电子激光光源处的新型高相干通量X射线束线依靠波前传感器在动态运行条件下实现并维持最佳对准。这包括对自适应X射线光学器件的反馈。我们描述了用于剪切干涉测量和哈特曼波前传感的一类新型二元振幅反射光栅的设计与建模。以掠入射角照射的深蚀刻光栅的紧凑阵列能够承受比透射膜更高的功率密度，并且可以设计成在固定的光栅到探测器距离下跨宽光子能量范围运行。利用相干波传播来研究阵列中单个元件的能量带宽并设定设计参数。我们观察到，在我们的配置中，剪切在±10%带宽内运行良好，而哈特曼可扩展到±30%或更高。我们将此方法应用于设计一个工作在230 eV至1400 eV的软X射线束线的波前传感器，并对存在不同波前像差类型和量级时的剪切和哈特曼测试进行建模。
