Development of an Ultra Fast Scanned Electron Beam X-ray CT
F. Fischer1, U. Hampel1, M. Bieberle1, E. Schleicher1 G. Mattausch2, H. Flaske2, R. Bartel2
Institute of Safety Research, Forschungszentrum Dresden-Rossendorf e.V., POB 51 01 19, 01314 Dresden, Germany, Email: F.Fischer@fzd.de
Fraunhofer-Institute of Electron Beam and Plasma Technology (FEP), Winterbergstraße 28, 01277 Dresden, Germany
Electron beam X-ray CT is a promising technique for the fast measurement of multiphase flows with frame rates of at least 1000 images per second. Thus, X-ray tomography in principle gives quantitatively accurate images of the flow at high resolution and it is non-intrusive since moderately radiation absorbing vessel walls can be penetrated. However, on the road to a technical realisation of such a technique within a computed tomography system many problems have to be solved. As a first prototype for scientific flow measurement application we devised and built a fast scanned electron beam X-ray tomography scanner. The heart of the scanner is a medium power electron beam unit that can be operated at up to 150 kV acceleration voltage and up to 65 mA electron beam current. The system further comprises all the typical components of an electron beam device, such as beam adjustment, beam focussing and beam deflection unit and the vacuum system. X-ray radiation is produced on a circular tungsten target that is water cooled. For X-ray detection we use a fast circular CZT detector comprising 240 elements of 1.5 mm x 1.5 mm active pixel area. The photonic converters are connected to a state-of-the-art detector electronics with gain selectable amplifiers, fully parallel analogue-to-digital conversion and online data storage within a 4 GB dynamic RAM. The whole system is controlled by an industrial PC via LabVIEW.
Keywords Ultra fast X-ray CT, multi phase flow measurement, scanned electron beam CT
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