J. Phys. IV France 118 (2004) 71-75
Étude structurale de nanomatériaux par diffraction X : utilisation d'un montage avec optique multicouche à collimation 2DL. Ortega, C. Bouchard, R. Bruyère et P. Bordet
Laboratoire de Cristallographie du CNRS, BP. 166, 38042 Grenoble Cedex 09, France
We present X-ray diffraction measurements from an experimental setup based on a two-dimensionally collimating optical element. This device consists of a parabolically bent W/Si multilayer (ML) with laterally graded period. Hence, with only one reflection, divergent X-rays from laboratory sources are converted into a nearly parallel beam. We focus on the possibility to use such an optic for the fine structural characterization of nanomaterials. A 4 nm thick epitaxial film of Tb(0001) deposited onto Al2O3(111) substrate was used as a test -sample. Although a large gain of photons with the ML optic is obtained in comparison with a setup using a flat graphite crystal as primary monochromator, the presence of high parasitic contributions (Cu K, W L radiations,) prevents from a fine analysis of the diffraction diagram. In order to overcome this effect we also made comparative tests using different analyzers. In particular the adjunction of a Ge(111) analyzer crystal led to a very good peak to background ratio suitable for the measurement of nanomaterials.
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