V4
Small Angle Scattering Instrument
(SANS)
Instrument description
V4 allows for the measurement of density composition and magnetization fluctuations in materials on a length scale from 0.5 nm to 400 nm. At short distance the 2D-detector can be moved vertically by 0.17 m, extending the Q range to even higher values. A large sample chamber is connected to the vacuum system with the detector and collimator tubes. Automatic sample changers (both T and B controlled) are available.
A high transmission supermirror polarizer can be introduced by remote control in front of the 12 m collimation without any modification of the instrument alignement. The polarization direction can be reversed by a RF gradient spin-flipper in front of the sample. The SANSPOL option is characterized by a high neutron flux of more than 30% of the non-polarized beam (wavelength dependent), a high degree of polarisation ( > 90%) and high efficiency of the spin-flipper ( > 95%) for λ< 1.8 nm without any additional background.
Using the list mode data acquisition time-stamped measurements can be performed. Stroboscopic measurements by using a trigger signal allow to investigate the kinetics of periodic processes. The chopper system based on TISANE technique allows for studies of microsecond dynamics.
Applications
- Nanoscaled materials
- Phase separation in alloys and glasses
- Morphologies of superalloys
- Magnetic correlations
- Microporosity in ceramics
- Interfaces and surfaces of catalysts
- Biological macromolecules
- Polymers and membranes
- Flux line lattices in superconductors
Selected examples
Time resolved SANSPOL investigations in concentrate Co-ferrofluids
Instrument layout
| Instrument Data | |
|---|---|
| Neutron guide | NL 3A |
| Collimation | Entrance window: 50x30 mm2 Collimator length: 2m, 4m , 8m, 12m (all also for SANSPOL), and 16m |
| Monochromator | Mechanical velocity selector |
| Wave length | 0.45 < λ < 2 nm |
| Wave length resolution | 8% < Δλ/λ < 18% FWHM |
| Flux | 4.6·106n/cm2 at λ=0.5 nm, Δλ/λ = 10% and collimation 2m |
| Q range | 0.01 nm-1 < Q < 8.5 nm-1 |
| Q resolution | |
| Detector | ca. 1 m diameter, 112 Reuter-Stokes tubes, 1000 mm / 850 mm / 600 mm |
| Sample-to-detector distance | Horizontal: 1 to 16m continuously Vertical offset: 0.17 m at short distance |
| Polarized neutrons | no longer supported |
| Instrument options | • Stroboscopic SANS • TISANE |
| Sample environment | • T-controlled automatic sample changer (5°C-80°C) |
| Software | BerSANS |
Data reduction software
The "BerSANS" data reduction software package has been developed by Uwe Keiderling, and is constantly being expanded to offer new options and data treatment tools. It contains a set of programs for automated two-dimensional and one-dimensional reduction of large amounts of data files, and a set of graphical tools for data analysis, documentation, and publication.