Radiography is an important technique to inspect objects, with applications in airports and hospitals. X-ray imaging is also essential in industry, for instance in food safety checks for the... Show moreRadiography is an important technique to inspect objects, with applications in airports and hospitals. X-ray imaging is also essential in industry, for instance in food safety checks for the presence of foreign objects. Computed tomography (CT) enables more accurate visualizations of an object in 3D, but requires more computation time. Spectral X-ray imaging is an important recent development to optimize these conflicting goals of speed and accuracy. This technique enables separation of detected X-ray photons in terms of energy. More information can be extracted from spectral images, which allows for better separation of materials. Deep learning is another important recent technique enabling machines to quickly carry out processing tasks, by training these with large volumes of data for these specific tasks.In this dissertation we present new processing methods that use spectral imaging and machine learning, with a special focus on industrial processes. We design a workflow using CT to efficiently generate large volumes of machine learning training data. In addition, we develop a compression method for efficient processing of large volumes of spectral data and two new spectral CT methods to produce more accurate reconstructions. The presented methods are designed for effective use in industry. Show less
The intracluster medium (ICM) is a hot, tenuous and X-ray emitting gas that pervades galaxy clusters. Meanwhile, extended synchrotron sources, i.e., radio relics and radio halos are frequently... Show moreThe intracluster medium (ICM) is a hot, tenuous and X-ray emitting gas that pervades galaxy clusters. Meanwhile, extended synchrotron sources, i.e., radio relics and radio halos are frequently observed in galaxy cluster, for which the two widely accepted particle acceleration are shock acceleration and turbulent acceleration, respectively. Both of these scenarios are due to ICM motions, which means that X-ray observations of the ICM are fundamental for quantifying shock wave and turbulence properties to test the acceleration models. This thesis focuses on X-ray observations of galaxy clusters, and covers topics from ICM shock - radio relic connection to turbulence - radio halo connection. The new observational evidences further support the two acceleration scenario. Show less
