Horizontal time-of-flight reflectometer
This instrument is focussed on cold neutrons. All parameters given here are valid during the current operation of FRM II. Please get in touch with the instrument team well in advance for all further details (length of experiment etc.).
The horizontal reflectometer REFSANS operates in time-of-flight mode (TOF), each measurement at a given incident angle providing a segment of the reflectivity curve. The useable wavelength band is in the range 4 Å to 7 Å. The accessible Qz range is expected to cover 5.0 · 10–3 – 0.12 Å–1. The wavelength resolution can be tuned between 3 % and 10 % by changing the chopper parameters.
The sample to detector distance can be adjusted between 1.5 and 12m.
The TOF-based reflectometry can be used to characterize thin films in general. Specular reflectometry provides information about the structure along the sample’s normal; off-specular reflectometry, using the full detector coverage, is sensitive to large scale in-plane correlations in the beam direction.
Typical reflectometry experiments include:
- Characterisation of polymer thin film structurein different ambient conditions (in a humidity chamber)
- Investigations of biological systems such supported membranes (e.g. determination of the morphology and localization of proteins at interfaces)
- Metallic thin films and multilayers
- Detection and identification of polymer lamellae in immiscible blends or semicrystalline systems
- Huber high-precision goniometer for rotation, translation, and height
- Trioptics Autocollimator system for a fast, easy and reliable sample alignment
- Vibration controlled NIMA 602XL Langmuir trough for liquid-air interfaces studies
- Gamry Reference 600+ Potentiostat/Galvanostat/ ZRA device for electrochemical investigations
- Magnetic fields up to 7 T
- Julabo Presto A40 Thermostat for temperature control in the range -20 ≤ T/°C≤ 80
- Furnace for solid-air interface investigations
- Automatable solvent exchange for contrast variation studies
Chopper system (Airbus Defence and Space)
- Size: 50 × 80 mm2 for solid-liquid and 70 × 70 mm2 for solid-gas interfaces. Different dimensions are of course possible.
- Sample changer for hosting up to five samples
- Typical wavelengths: 4 ≤ λ/Å ≤ 7
- Wavelength resolution: 3 % ≤ Δλ/λ ≤ 10 %
Detector (DENEX DNX-700 TN)
- Collimation length variable from 2.5 m up to 8.9 m defined by two vertical adjustable slits (0 – 12 mm)
- Maximum beam size at sample position: 12 mm x 80 mm (h x w)
- Tiltable optic elements settable to neutron guide, vertical collimated, and full collimated modes. For NR the horizontal divergence is maximized by means of supermirrors (m = 2 – 3)
- Typical incident angles for downward bent beam: 0.70 deg and 2.75 deg
- High-resolution, position sensitive, multiwire 3He Detector
- Size: 500 × 680 mm2
- Pixel size: 2.1 mm (H) × 2.9 mm (V)
- Sample – detector distance: from 1.5 m to 12 m
- List mode acquisition, allowing optimization of the resolution/ intensity trade-off AFTER the experiment.
Dr. Jean-François Moulin
Phone: +49 (0)89 289-10762
Dr. Gaetano Mangiapia
Phone: +49 (0)89 158860-839
Phone: +49 (0)89 158860-763
Phone: +49 (0)89 158860-550
Find the latest publications regarding REFSANS in our publication database iMPULSE:
Citation of the instrument
Heinz Maier-Leibnitz Zentrum. (2015). REFSANS: Reflectometer and evanescent wave small angle neutron spectrometer. Journal of large-scale research facilities, 1, A9. http://dx.doi.org/10.17815/jlsrf-1-31
For citation please always include the DOI.
© W. Schürmann, TUM
Figure 1: The GISANS focusing channels (used in NGE3 and 4).
Figure 2: Typical reflectivity curve. Obtained for a biological sample (POPC/POPS Phospholipid bilayer supported on Si).
Reconstructed Bragg rods
Figure 3: Bragg rods reconstructed from the GISANS pattern of a nanostructured Gd samples (horizontal wires with spacing 250 nm). The annotation marks the expected peak positions.