&Bullet; physics 14, p63
Researchers have downsized x-ray pptchography – a high-resolution imaging technique that previously required large, expensive facilities – for use in the laboratory.
X-rayptychography is a powerful new technique that uses the quantitative phase information in the transmitted radiation to create images with a resolution of nanometers. Researchers have used the method to map everything from biological tissues to archaeological artifacts to semiconductor nanostructures. Until now, however, the required intensive and coherent X-ray sources were only available in expensive synchrotron or free-electron laser systems. Darren Batey of Diamond Light Source in the UK and colleagues hope to change that by demonstrating a ptychography technique that uses a more accessible laboratory-scale x-ray source  .
As with traditional x-ray pithography, the team’s method involves scanning an object with a coherent x-ray beam and reconstructing an image from the resulting interference patterns. The quality of the image depends on the amount of coherent x-rays. Therefore, Batey and colleagues use the most powerful laboratory x-ray source available. This source generates x-rays by striking electrons into a liquid gallium target, tolerating electron currents that would melt the solid metal target in a standard laboratory-scale x-ray source. Even so, this source is still much weaker than synchrotrons and free-electron lasers, and its output extends over a wider range of frequencies.
To compensate for the source’s wide frequency range, researchers use a photon counting detector that contains a spectrometer that narrows the radiation bandwidth after collection. To compensate for the relative lack of intensity, they use a reconstruction algorithm that is robust to beam instabilities that can occur during the necessarily long acquisition times. The researchers say that by integrating these innovations it is now possible to transfer the analytical power of ptychographic X-ray imaging directly to universities and hospitals, making it a routine tool for research, teaching, and medical diagnostics.
Sophia Chen is a freelance science writer based in Columbus, Ohio.
- DJ Batey et al., “X-ray ppt with a laboratory source” Phys. Rev. Lett.126193902 (2021).