This article showcases the high-resolution control of an elliptically bent hard X-ray mirror optics at the Advanced Photon Source. The mirror uses a compact laminar flexure bending mechanism to achieve elliptical shapes covering a large range of focal distances. An array of capacitive sensors are used as a surface profiler for in-situ monitoring of the mirror shape. Machine learning and control techniques were used to change the mirror shape and focus the incident X-ray at predefined focal planes. The mirror surface shape error can be controlled to be within 40 nm rms with high repeatability. This technique gives the capability to focus incident X-ray beam within a range of focal distances corresponding to shape deformation range of a mirror optics. This work would be beneficial for controlling similar adaptive optics for multiple adaptive optics systems.
The wavelet-transform-based single-shot X-ray speckle tracking (WXST) method combined with a multi-resolution analysis process was proposed to provide higher noise robustness and faster data processing compared with the correlation-based single-shot X-ray speckle tracking (CXST) technique. The new method was experimentally validated by measuring phase errors of beryllium compound refractive lenses in the transmission geometry. Taking advantages of the wavelet transform and the multi-resolution analysis, the data-analysis efficiency can be improved by two orders of magnitude for samples with phase variation over a large dynamical range. The multiresolution WXST method also shows high reconstruction accuracy and noise robustness. This novel method can broaden the potential applications of speckle-tracking techniques in wavefront sensing, at-wavelength metrology and phase imaging by breaking the bottleneck of the data processing.
Mirror-based zoom optics systems can offer variable focal spot sizes over a wide range, which is essential for coherent nanoprobe beamlines, such as the proposed Atomic beamline in the Advanced Photon Source (APS) upgrade project. The success of the zoom mirror system in the nano-focusing regime requires the development of high-precision deformable mirrors, in-situ surface profilers and wavefront sensors, and advanced feedback control system. A prototype 1-D zoom mirror system consists of two vertical focusing mirrors was designed, assembled, and tested at the APS 1-BM beamline. The system consists of a bender-based mirror with a capacitive-sensor- array-based real-time mirror profiler, a bimorph adaptive mirror, and a grating interferometer for the wavefront monitoring. In this work, we present the design and test results of the prototype system demonstrating its zoom focusing capability.