Applications and methods with high energy CT systems

The increase of Computed Tomography (CT) as an applicable method for non-destructive testing (NDT) and metrology awakes interest on expanding the application fields, on which CT was rarely applied in the past due to their requirements on the imaging system. Especially the classical X-ray generation techniques based on bipolar high voltage (HV) supplies restricted the application fields of CT to typical material penetration lengths of only a few cm of steel. Even with accelerator technology that offers a suitable way to overcome these restrictions only the 2D radioscopy technique found a widespread application. Beside the generation and detection of photons in the MeV range itself, the achievable image quality is limited using standard detectors due to the dominating absorption effect of Compton scattering at high energies. Especially for CT reconstruction purposes these effects have to be considered on the development path from classical 2D radioscopy to 3D imaging. Most High Energy CT applications are therefore based on line detectors shielding scattered radiation to a maximum with an increase in imaging quality but with time consuming large volume scan capabilities. In this contribution we present the High-Energy X-ray Imaging facility at the Fraunhofer Development Centre for X-ray Technology in Fürth with regards to the potential of the CT-system stage according to metrological and other application capabilities and to the conceptual tasks due to the construction and development of the CT system until now and for the future stages. Results of the investigation on achievable scan quality on different objects are presented compared to state of the art 450 kV X-ray systems.