Obtaining color images from the shadow of a sample

Obtaining color images from the shadow of a sample

Artist rendering showing how an image is created using the newly developed method. Two colors – green and magenta – are emitted by fluorescent atoms in the sample (left) due to X-ray excitation. The round gray object is an optic that casts a shadow on the detector. The algorithm then produces a real two-color image—the intensity of which represents the density of fluorescent atoms in the sample. Credit: Markus Osterhoff

A research team from the University of Göttingen has developed a new method to produce color X-ray images. In the past, the only way to determine the chemical composition of a sample and the position of its components using X-ray fluorescence analysis was to focus the X-rays and scan the entire sample. This takes time and is expensive. Scientists have now developed an approach that allows an image of a large area to be produced in a single exposure, without the need for focusing and scanning. The method was published in the journal OPTICAL.


Unlike visible light, there are no comparably strong lenses for “invisible” radiation such as X-rays, neutrons, or gamma rays. However, these types of radiation are essential, for example, in nuclear medicine and radiology, as well as in industrial testing and material analysis. Uses for X-ray fluorescence include analyzing the chemical composition of paintings and cultural artifacts to determine authenticity, origin, or production technique, or analyzing soil or plant samples in environmental protection. The quality and purity of semiconductor components and computer chips can also be checked using X-ray fluorescence analysis.

For their new method, the scientists used a color X-ray camera developed by PNSensor in Munich and a new imaging system that essentially consists of a specially structured gold-coated plate between the object and the detector, which means that the sample casts a shadow. . The intensity pattern measured in the detector provides information about the distribution of fluorescent atoms in the sample, which can then be decoded using a computer algorithm. This new approach means that the plate can be very close to the object or detector, unlike using an X-ray lens, making it a practical method.

“We developed an algorithm that allows us to quickly and robustly create a sharp image simultaneously for each X-ray color,” explains first author Dr. Jakob Soltau, a postdoctoral researcher at the Institute for X-ray Physics at the University of Göttingen.

Co-author Paul Meyer, a PhD student at the same institute, adds: “The optics simply cannot be compared to normal lenses; were manufactured to our exact specifications by a new company in Switzerland”. This start-up company, XRNanotech, specializes in nanostructures and was founded by Dr. Florian Döhring, who completed his Ph.D. at the University of Göttingen.

Research group leader Professor Tim Salditt concludes: “Next, we want to extend this approach to three-dimensional imaging of biological samples, as well as explore imaging phenomena such as inelastic scattering of X-rays, neutrons or gamma radiation in nuclear medicine. ”

More information:
Jakob Soltau et al., Full-field X-ray fluorescence imaging using a coded aperture Fresnel zone plate, OPTICAL (2022). DOI: 10.1364/OPTICA.477809

Provided by the University of Göttingen

Citation: Obtaining color images from the shadow of a sample (2023, January 24) Retrieved January 25, 2023 from https://phys.org/news/2023-01-images-shadow-sample.html

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