Concept for a nanometer-resolution X-ray computed tomography system for non-destructive testing based on room temperature semiconductor detector modules

Abstract

In the nanotechnology sector there is a strong need for non-destructive testing instruments that can reveal the inner structure of objects. For such applications we developed a concept for a novel nanometer-resolution X-ray computed tomography (CT) system, which does not rely on the use of X-ray optics. We target a resolution in the range of existing nano CT setups (50 to 150 nm) while increasing the field-of-view by an order of magnitude. Our calculations on the performance of the planned system give promising results. We present possible design goals, such as spatial resolution, object size and show typical limits (source intensity, power, pixel pitch, etc.) for such a system. The fundamentals for calculations to obtain estimates on the system parameters are discussed. The required detector and system properties, including focus-to-object and focus-to-detector distances and resulting measurement times for this approach and their relations are shown. On this basis, a feasible concept for the measurement system is proposed. Currently, large-area, high-resolution detectors with suitable properties, like dynamic range especially at low flux and efficiency, are not yet commercially available. The detector will be based on photon counting room temperature semiconductor detector modules that are currently available. A concept for the arrangement of multiple detector modules that are not four-side tileable is presented. A solution for coping with the resulting gaps for X-ray CT applications is illuminated. In summary this paper discusses the results and perspectives based on the emerging possibilities of the planned system.