Regensburg 2013 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 8: Poster: New Instruments and Methods
CPP 8.15: Poster
Montag, 11. März 2013, 17:30–19:30, Poster C
Bispectral powder diffraction at the long pulse source ESS — •Nicolò Violini1, Werner Schweika1,2, Andreas Houben3, Klaus Lieutenant4, and Paul F. Henry2 — 1JCNS, Forschungszentrum Jülich GmbH, D-52425 Jülich Germany — 2European Spallation Source ESS AB, Lund, Sweden — 3RWTH Aachen University, Germany — 4Helmholtz-Centre Berlin, Germany
Within the ESS Design Update Program, funded by the German Federal Ministry of Education and Research, we investigate a versatile instrument concept for powder diffraction at the ESS. Typical applications will be the determination of structures involving light or neighboring elements, complex magnetic structures, and the ability to in-situ follow phase transitions in reactive or functional materials, under conditions close to operation. To match the various needs, we investigate a bispectral time-of-flight diffractometer that efficiently makes use of thermal and cold neutrons (0.8-4.6Å). Moreover a wide wavelength spectrum is of interest to exploit the backscattering option with high resolution. The conceptual design utilizes a 10x10mm2 eye-of-the-needle[1] at 6m from the source, defining an image of 5 to 10 mm diameter with an initial divergence of +/-0.6∘. It reduces background by more than two orders of magnitude, as early as possible, thus it helps to design more cost-efficient shielding. It allows to fit in counter rotating disc choppers that are able to provide flexible resolution from 10 µs to 1 ms. The desired phase space is transported by elliptic guides to the sample position of similar size, with only small losses. [1] A. Houben et al., NIMA, 2012, 680, 124.