GPU implementation of simulation framework
Simulations provide a powerful tool to gain insight into complex systems by either simplifying the problem or the control of all involved parameters. Computer assisted scientific work is nowadays an integral part of understanding or applying the theoretical background to a studied field. For X-ray imaging one option is the simulation of Fourier optics in the form of Fresnel propagation. It allows to optimize system parameters and simulate the effect of known system imperfections onto the imaging capabilities. The goal of this project is to improve the time efficiency of our existing framework by moving the computations onto the GPU and use the optimized platform for a grid-search analysis to find optimal setup parameters.
Mechanical design of a dual-phase grating holder
Grating alignment for phase sensitive X-ray imaging is a crucial part of system optimization. Due to the small structure sizes of the optical components, the alignment of the individual parts has to be performed with on length scales below these structures. This can be done with piezo-motors, which can align objects on the order of a few nanometres. While this accuracy is unchallenged, the amount of freedom makes the optimization of the alignment difficult, time consuming and tedious. Since not all degrees of freedom need to be controlled with the same precision, mechanical fixtures allow to confine the gratings in most of the degrees of freedom, while still allowing to fine tune a few important parameters. This project is aimed to design such a holder for our dual-phase system.
Bending gratings for refraction-based x-ray imaging
Refraction-sensitve x-ray imaging relies on large optical elements with coherent microstructures. These are often manufactured in silicon with methods similar to the ones in the chip-making industry. For large-field-of-view imaging the silicon wafers with the optical element etched into it needs to be precisely bent. The project is about investigation of the limits of the precision of the bending, as well as the minimal possible radius. It will involve theoretical mechanical considerations, design of test fixtures for bending and test measurements: both purely mechanical and in the x-ray beam. The result project is part of a larger effort to built a clinical refraction-sensitive dedicated breast CT system.
Mechanical design of an ultra-stable x-ray interferometer
Refraction-based x-ray imaging can greatly improve clinical CT. The refraction angles for x-rays are, however, very small, and thus the structure of optical elements of refraction- sensitive systems need to in the as small as a few micrometres and as far apart as two metres. They also need to remain stable on a sub-micrometre level throughout the imaging process. The project is a mechanical design of a Talbot-Lau interferometer that would remain stable even in a clinical conditions.

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