Probing MHz processes in 3D with X-ray microscopy

ongoing

I aim to develop an X-ray imaging technique capable of filming processes in 3D, with a temporal resolution several orders of magnitude faster than up-to-date 3D X-ray imaging techniques. The unique penetration power of X-rays allows us to study systems in their native environment. This property has led to the development of X-ray microtomography (µCT). µCT acquires 3D information, which determines the functionality and mechanical properties of nature, by rotating a sample with respect to the X-ray source. µCT is a crucial tool for several scientific disciplines such as physics, biology, and chemistry. Over the last decade, µCT has become a technique capable of not only recording 3D information but also filming dynamical processes. Several breakthroughs have made this possible: i) intense X-ray sources (synchrotron light sources), ii) efficient and fast X-ray detectors, and iii) fast 3D reconstruction algorithms. Despite all of these developments, the acquisition protocols remain unchanged, i.e., the sample is only rotated faster. This fast rotation introduces forces which may alter the studied dynamics and ultimately limit the achievable temporal resolution. My project is to establish an X-ray microscope that avoids the sample rotation, obtaining 3D information from a single X-ray flash by splitting it into nine-angularly resolved beams which illuminate the sample simultaneously. This approach, when implemented at intense X-ray sources such as synchrotron light sources and X-ray free-electron lasers, will allow the filming of natural processes with micrometer to nanometer resolution and resolve dynamics from microseconds to femtoseconds. To demonstrate its capabilities, I will study fundamental processes in cellulose fibers, a renewable biomaterial, which can replace fossil-based materials, such as plastics. This technique will open up the possibility to film dynamics in 3D to answer questions coming from industry and natural sciences at rates not accessible today.