The APS Upgrade (APS-U) will be capable of producing 100% brighter X-rays than the current APS. This brighter beam will allow for X-ray data collection with greater detail in shorter time. To complement the APS-U, fast and robust scanning of X-ray microscopes, in real-time with nm to sub-nm positioning resolution, and large tracking bandwidth is necessary. Proper operation of the X-ray microscope is dependent on high-precision scanning of the optics or sample, high relative stability of the sample with respect to optics, and high stability of the whole microscope structure under environmental disturbance from facility vibration and temperature fluctuations.

The Velociprobe is a next-generation X-ray microscope built from the ground up with fast, stable scanning in mind to take advantage of the APS-U flux. Funded with a LDRD, the goal is to scan a 1 µm by 1 µm area at sub-10 nm resolution, in less than 10 seconds. To that end, we are showcasing an optimal scanning control architecture that gives the flexibility of incorporating multitude of closed-loop objectives such as large tracking bandwidth, good positioning resolution, robustness to unmodeled system dynamics, good disturbance rejection and adequate noise attenuation. Large tracking bandwidth, less than 1% tracking error, and sub-nm positioning resolution were achieved by implementing the control algorithm on the 3DOF fine-scanning nanopositioning system in a lab setup at APS. X-ray imaging technique such as ptychography can achieve better image resolution and imaging bandwidth boosted by the sub-nm positioning resolution, large tracking bandwidth with small tracking error of the fine-scanning optics. This would benefit the future APS-U users and enable them to carry on novel X-ray science.