Novel digital K-edge imaging system with transition radiation from an 855-MeV electron beam

Autor: K. Johann, H. Matthay, Werner Lauth, M. Zemter, F. Hagenbuck, C. von Zanthier, H. Euteneuer, N. Clawiter, Hartmut Backe, L. Struder, M. Schutrumpf, Th. Kerschner, R. Stötter, P. Holl, K. H. Kaiser, Th. Walcher, Herbert Koch, G. Kube, J. Kemmer, O. Kettig, A. Wilms, F. Görgen
Rok vydání: 2001
Předmět:
Zdroj: IEEE Transactions on Nuclear Science. 48:843-848
ISSN: 1558-1578
0018-9499
DOI: 10.1109/23.940173
Popis: A novel K-edge imaging method has been developed at the Mainz Microtron MAMI aiming at a very efficient use of the transition radiation (TR) flux generated by the external 855-MeV electron beam in a foil stack. A fan-like quasi-monochromatic hard X-ray beam is produced from the /spl plusmn/1-mrad-wide TR cone with a highly oriented pyrolytic graphite (HOPG) crystal. The absorption of the object in front of a 30 mm/spl times/10 mm pn charge-coupled device (pn-CCD) photon detector is measured at every pixel by a broad-band energy scan around the K-absorption edge. This is accomplished by a synchronous variation of the lateral crystal position and the electron beam direction which defines also the direction of the TR cone. The system has been checked with a phantom consisting of a 2.5-/spl mu/m thick molybdenum sample embedded in a 136- or 272-/spl mu/m-thick copper bulk foil. A numerical analysis of the energy spectrum for every pixel demonstrates that data as far as /spl plusmn/0.75 keV away from the K edge of molybdenum at 20 keV still improve the signal-to-noise ratio (SNR). Prospects are discussed to investigate the human lungs with xenon as a contrast agent at the available total primary photon flux of 2/spl times/10/sup 10//(s/spl middot/0.1% bandwidth (BW)) only.
Databáze: OpenAIRE
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