Time-Resolved 3D X-ray Imaging without Sample Rotation

What is it about?

This work presents X-ray multi-projection imaging (XMPI), a method for observing how a sample changes in 3D over time. Usually, obtaining 3D information requires rotating the sample to record images from many angles. This rotation can be difficult or even impossible for sensitive samples or very fast processes. In XMPI, the sample does not need to be rotated. Instead, the incoming X-ray beam is split into several sub-beams that illuminate the sample from different directions at the same time. Images from these different views are recorded simultaneously and combined to create a 3D picture of the sample. By continuously recording images, we can follow how the sample changes over time. Because all views are captured at once, each measurement represents a single 3D snapshot. This makes it possible to study rotation-sensitive samples and to perform single-shot 3D experiments. We have set up this technique at the ForMAX beamline at MAX IV, where it can capture very fast sample dynamics, up to thousands of images per second, with micrometer resolution. This opens new opportunities for in-situ and operando 4D imaging.

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Photo by Wolfgang Weiser on Unsplash

Photo by Wolfgang Weiser on Unsplash

Why is it important?

Conventional imaging methods require rotating the sample to capture images from different angles, which are then used to reconstruct the 3D volume. However, rotating the sample can cause several problems: 1. Some sample environments are too large or complex to rotate. 2. Rotation can introduce centrifugal forces that disturb the process under study. 3. Rotation stages are often too slow to capture very fast sample dynamics. 4. Rotation is not suitable for single-shot experiments. Consequently, XMPI can investigate research questions not accessible with traditional imaging methods. XMPI can be applied to many types of dynamic processes, such as fiber breakage, additive manufacturing, and fluid flows, to name just a few.