MLZ is a cooperation between:> Technische Universität München> Helmholtz-Zentrum Geesthacht> Forschungszentrum Jülich
The high resolution neutron/ X-ray contrast reflectometer NREX, operated by the Max Planck Institute for Solid State Research, is designed for the determination of structural and magnetic properties of surfaces, interfaces, and thin film systems.
The instrument is an angle-dispersive fixed-wavelength machine with a default wavelength of 4.28 Å. A horizontal focussing monochromator gives the possibility to switch between modes “high intensity/ relaxed resolution” and “high resolution/ reduced intensity” and provides a beam especially for small samples (down to 5 × 5 mm2 and below). A Beryllium filter attenuates higher order reflections. Transmittance supermirrors m = 3.5 with a polarising efficiency of P = 99% and high efficiency gradient RF field spin flippers are used for a full 4 spin channel polarisation analysis.
The sample is aligned horizontally. By tilting the sample the incident angle is varied. The detector arm can move for GISANS horizontally as well as vertically for specular and diffuse scattering measurements. Neutrons are detected with a 20 x 20 cm² position sensitive or a pencil detector. An X-ray reflectometer can be mounted on the sample table orthogonal to the neutron beam. It allows for the in-situ characterisation of sensitive soft matter samples and neutron/ X-ray contrast variation experiments.
The instrument provides specular and off-specular reflectometry as well as grazing incidence small angle diffraction both in polarised and non-polarised modes. While the specular reflectivity allows determining the scattering length density profiles (20 – 1500 Å) with nm precession along the surface normal, the off specular reflectivity is sensitive to in-plane-inhomogeneity like roughness, (magnetic) domains, vortices in superconductors- and clusters- in the µm-range. To probe lateral (in-plane) structures in the order of atom distance (down to few Å) at the surface, grazing incidence diffraction is provided.
A closed cycle crystat (down to 3.5 K) and an electromagnet for fields up to 0.5 T applicable in all three space-directions with restrictions in field strength are provided. Additionally the standard sample environment (magnets up to 7,5 T and 3He inserts for the cryostat down to 50 mK) are available. To the instrument pool belong a cell for investigations at the solid/ liquid interface and a gastight chamber for experiments under defined environmental conditions (arbitrary atmospheres: for example defined relative humidity) at the solid/ air interface.
|Type||7 × 5 HOPG crystals|
|Distance to sample||2500 mm|
|Higher order filter||cooled Be|
|Slit sizes||0.2 – 6 mm|
|Divergence||0.05 – 1.4 mrad|
|Slit||0.2 – 100 mm|
|Beam polarisation||> 99%|
|Flipper efficiency||> 99%|
|2 pencil detectors||3He|
|2D area detector||3He wire chamber|
|Active area||200 × 200 mm2|
|Lateral resolution||3 mm|
|Distance to sample||2465 mm|
|Dynamical- and Q-Range|
|Specular reflectivity||1 : 1 × 10-6 (@ 5 × 5 mm² sample and full polarisation)|
|Qz||0.005 – 0. 5 Å-1|
|δQz (0 < Qz < 0.2 Å-1)||< 0.002 Å-1|
Dr. Yury Khaydukov
Phone: +49 (0)89 289-14769
Dr. Olaf Soltwedel
Phone: +49 (0)89 289-14769
Dr. Thomas Keller
Phone: +49 (0)89 289-12164
Phone: +49 (0)89 289-14878
Find the latest publications regarding NREX in our publication database iMPULSE:
Max-Planck-Institut für Festkörperforschung and Heinz Maier-Leibnitz Zentrum. (2015). NREX: Neutron reflectometer with X-ray option. Journal of large-scale research facilities, 1, A38. http://dx.doi.org/10.17815/jlsrf-1-30
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