The Velociprobe: An ultrafast hard X-ray nanoprobe for high-resolution ptychographic imaging

Abstract

Motivated by the advanced photon source upgrade, a new hard X-ray microscope called “Velociprobe” has been recently designed and built for fast ptychographic imaging with high spatial resolution. We are addressing the challenges of high-resolution and fast scanning with novel hardware designs, advanced motion controls, and new data acquisition strategies, including the use of high-bandwidth interferometric measurements. The use of granite, air-bearing-supported stages provides the necessary long travel ranges for coarse motion to accommodate real samples and variable energy operation while remaining highly stable during fine scanning. Scanning the low-mass zone plate enables high-speed and high-precision motion of the probe over the sample. With an advanced control algorithm implemented in a closed-loop feedback system, the setup achieves a position resolution (3σ) of 2 nm. The instrument performance is evaluated by 2D fly-scan ptychography with our developed data acquisition strategies. A spatial resolution of 8.8 nm has been demonstrated on a Au test sample with a detector continuous frame rate of 200 Hz. Using a higher flux X-ray source provided by double-multilayer monochromator, we achieve 10 nm resolution for an integrated circuit sample in an ultrafast scan with a detector’s full continuous frame rate of 3000 Hz (0.33 ms per exposure), resulting in an outstanding imaging rate of 9 × 104 resolution elements per second.

Sub-1.4eV bandgap inorganic perovskite solar cells with long-term stability

“…Time-integrated photoluminescence spectra were excited at 405 nm also and measured with a CCD camera. Synchrotron-based X-ray ptychography was performed at the Velociprobe 49 located at 2-ID-D beamline at the Advanced Photon Source (APS) in Argonne National Laboratory. An 8.8-keV monochromatic X-ray beam was focused by a Fresnel zone plate with an outer zone width of 50 nm.…”

First ptychographic X-ray computed tomography experiment on the NanoMAX beamline

“…As of now, the position of the sample is only measured by the encoders of the piezo-scanning stage. Additional independent sample tracking via interferometers as utilized in similar setups (Schroer et al, 2017;Holler et al, 2018Holler et al, , 2020Deng et al, 2019;Tolentino et al, 2019) is desirable, as positional errors are more difficult to handle with measurements using a small probing beam, due to the smaller absolute overlap between neighbouring positions. Interferometers would also allow direct measurement of the required relative positions between the (housing of the) optics and the sample, with high accuracy and separate from any encoder measurements.…”

Multi-beam X-ray ptychography for high-throughput coherent diffraction imaging

“…A fly-scan ptychography was conducted with these two beams on this gold sample with a 100 nm step size in both horizontal and vertical directions and an exposure time of 10 ms, resulting in 10 min data acquisition time covering a FOV of for each beam. The data acquisition time can be further improved by using advanced fly-scan trajectory, such as snake-raster scan pattern and spiral-scan pattern 33 . In the reconstruction, both probe functions used an array size of 128 128 pixels, giving a 25.6 nm pixel size in the real space.…”

“…S2 and Fig. 5 in the reference paper 34 ) on different areas but on the same window acquired by a high-resolution ptychography instrument-the Velociprobe 33 . Therefore, the line patterns are real and are presumably due to the defects from the fabrication process, displaying the parallelogram (or trapezoid) filling scheme of electron beam lithography 35 .…”