PSI Microspectroscopy group develops supersampled STXM imaging protocol at PSI’s SLS PolLux and Bessy II MAXYMUS; imaging overheads nearly eliminated and vibrations corrected
Supersampled Scanning Transmission X-ray Microscopy | Microspectroscopy Group | PSI
Supersampled Scanning Transmission X-ray Microscopy
Researchers from the Microspectroscopy group at PSI in a collaboration with the MAXYMUS beamline of Bessy II and the Max-Born-Institute have developed a novel scanning transmission X-ray microscopy (STXM) imaging protocol, dubbed supersampled scanning microscopy , that allows one to fully compensate for common-mode vibration artifacts and to minimize imaging overheads for low pixel dwell times. The work has been published in the journal Small .
In STXM, a monochromatic X-ray beam is focused onto a nanometric spot on the surface of an X-ray transparent sample by means of a diffractive optical element (Fresnel zoneplate - FZP). An image is acquired by scanning the sample by means of a piezoelectric positioner and measuring the intensity of the transmitted X-ray beam at each point of the scan. Therefore, the acquisition of high-resolution STXM images requires a very precise positioning of the sample with respect to the FZP. With the standard STXM imaging protocol, there are two significant challenges: mechanical vibrations at timescales faster than the pixel dwell time reduce the achievable resolution and the requirement for high precision positioning needed for high-resolution imaging leads to large imaging overheads, especially at low pixel dwell times. With the significant increases in coherent photon flux offered by the undergoing upgrades of synchrotron light sources to diffraction-limited synchrotron light sources, lower pixel dwell times will be possible, requiring the tackling of the imaging overheads to avoid negative impacts on the beamtime usage efficiency.
Supersampled scanning microscopy is an imaging protocol that allows us to almost completely eliminate imaging overheads whilst providing a way to correct for common-mode vibration artifacts in the images. The method consists in the use of a dedicated field-programmable gate array (FPGA) setup to measure the position of the sample and the transmitted photon intensity at a high rate (4 kHz - above most of the vibration modes of the setup). The piezoelectric stage is then scanned as fast as possible with minimal positioning feedback and the final image is reconstructed from the recorded sample positions and transmitted photon intensity by binning the data in a regular grid with user-defined pixel size.
Proof-of-concept measurements on both the reduction of the imaging overhead and on the possibility to correct for common-mode vibration artifacts were carried out at both the PolLux endstation at the SLS and at the MAXYMUS endstation of the Bessy II light source. In both cases, the imaging protocol exceeded the expectations in terms of improvement of image quality and beamtime usage efficiency.
The supersampled imaging protocol is compatible both with tiling mode scanning (allowing for large regions to be scanned) and with pump-probe time-resolved imaging. This setup is now being introduced to the PolLux beamline and will be available for user experiments.
Contacts: Dr. Simone Finizio Swiss Light Source Paul Scherrer Institut Telephone: +41 56 310 3961 E-mail: simone.finizio@psi.ch
Dr. Jörg Raabe Swiss Light Source Paul Scherrer Institut Telephone: +41 56 310 5193 E-mail: joerg.raabe@psi.ch
Supersampled Scanning Transmission X-Ray Microscopy for High-Resolution Vibration-Independent Time-Resolved Imaging Simone Finizio, Benjamin Watts, Benedikt Rösner, Tim A. Butcher, Sebastian Wintz, Markus Weigand, and Jörg Raabe Small, e74569 (2026), DOI: 10.1002
Share Article Facebook LinkedIn Mail X (Twitter)
Supersampled Scanning Transmission X-Ray Microscopy for High-Resolution Vibration-Independent Time-Resolved Imaging
PSI Center for Photon Science