Regensburg 2016 – scientific programme

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MI: Fachverband Mikrosonden

MI 7: Poster: Microanalysis and Microscopy

MI 7.6: Poster

Wednesday, March 9, 2016, 18:00–20:00, Poster E

Ultra-narrow germanium-slits for laboratory and synchrotron x-ray applications — •F. Döring, S. Hoffmann, M. Kanbach, and Tim Salditt — Institute for X-Ray Physics, University of Göttingen

Modern nano-beam x-ray diffraction and imaging applications rely on precise optical elements for beam focusing and shaping. We have recently developed x-ray waveguide optics to deliver coherence and wavefront filtered beams confined down to below 20 nm. While these optics are well suited for coherent imaging applications with synchrotron radiation, the transmission is too low for laboratory applications. Here we investigate the transition from a x-ray waveguide to a nanoscale slit suitable for laboratory and synchrotron applications in a setting of low and medium brilliance. Therefore, we aim at a larger angular acceptance of the beam, requiring a smaller optical thickness so that the mode structure is not yet fully developed, while the absorption must be sufficiently high. So, we replace silicon by germanium and adapt the processes of silicon based waveguide fabrication to germanium slit production. We use a lithographic manufacturing process at 400 nm in combination with reactive ion etching (RIE) and germanium wafer bonding. Along the vertical direction, the slit size shall be varied from 100 nm up to 1 µm as controlled by RIE parameters, while the horizontal size is controlled by UV exposure and varied in the range between 1 µm and 1.5 mm. The slit length is selected according to the required photon energy, ranging from 200 µm to 1 mm, for 8-20 keV photon energy, respectively. The fabrication is guided by finite differences simulation.