College Park, Maryland June 6 - 10 , 2004
WP26: ToF-Neutron Reflectometer REFSANS at FRM-II Munich / Germany: Design and Potential for Investigations on Surfaces and Interfaces
R. Kampmann, M. Haese-Seiller, V. Kudryashov (Institut für Werkstoffforschung, GKSS-Forschungszentrum Geesthacht GmbH, D-21502 Geesthacht, Germany), A. Okorokov, B. Toperverg (Petersburg Nuclear Physics Institute, Gatchina, 188350, Russian Federation), A. Schreyer (Institut für Werkstoffforschung, GKSS-Forschungszentrum Geesthacht GmbH, D-21502 Geesthacht, Germany), E. Sackmann (Physik-Department E22, Technical University Munich, 85748 Garching, Germany)
The reflectometer REFSANS is being built at the high flux reactor FRM-II in Munich. Novel time-of-flight (TOF) design and neutron optics allow for equal resolution adjustment of both the wavelength and the incidence angle to measure the specular reflectivity at maximum beam intensity over an extremely large range of momentum transfer of ~0.02 nm-1 < q < 20.0 nm-1. The resolution in momentum transfer can be set in the wide range of 0.25% < Δq/q < 15% (FWHM). At low q-resolution, beam intensities are expected to be sufficiently high to measure minimum reflectivities of R ~ 10-10. REFSANS also provides new perspectives for characterizing lateral surface structures by means of small-angle scattering at grazing incidence (GI-SANS). Such experiments can be performed with the highest beam flux at a low wavelength resolution of Δλ/λ ~10% and with novel scattering geometries, in particular the option to focus 13 point-collimated or slit height-smeared beams in the detector plane. Polarized neutrons can be used optionally for all mentioned scattering geometries and 3He-based polarization analysis will be made available in 2005. REFSANS is being put into operation this year and will be open for national as well as international users.
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