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Title: Wavelength-independent constant period spin-echo modulated small angle neutron scattering

Abstract

Spin-Echo Modulated Small Angle Neutron Scattering (SEMSANS) in Time-of-Flight (ToF) mode has been shown to be a promising technique for measuring (very) small angle neutron scattering (SANS) signals and performing quantitative Dark-Field Imaging (DFI), i.e., SANS with 2D spatial resolution. However, the wavelength dependence of the modulation period in the ToF spin-echo mode has so far limited the useful modulation periods to those resolvable with the limited spatial resolution of the detectors available. Here we present our results of an approach to keep the period of the induced modulation constant for the wavelengths utilised in ToF. This is achieved by ramping the magnetic fields in the coils responsible for creating the spatially modulated beam in synchronisation with the neutron pulse, thus keeping the modulation period constant for all wavelengths. Such a setup enables the decoupling of the spatial detector resolution from the resolution of the modulation period by the use of slits or gratings in analogy to the approach in grating-based neutron DFI.

Authors:
 [1]; ;  [2];  [3];  [4];  [1];  [5]
  1. Nano-Science Center, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark)
  2. Faculty of Applied Sciences, Delft University of Technology, 2629 JB Delft (Netherlands)
  3. Helmholtz-Zentrum Berlin für Materialen und Energie GmbH, D-14109 Berlin (Germany)
  4. Space Sciences Laboratory, University of California at Berkeley, Berkeley, California 94720 (United States)
  5. (Sweden)
Publication Date:
OSTI Identifier:
22597913
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 87; Journal Issue: 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BEAMS; DECOUPLING; FREQUENCY DEPENDENCE; GRATINGS; IMAGES; MAGNETIC FIELDS; MODULATION; NEUTRON DIFFRACTION; NEUTRONS; PULSES; SIGNALS; SMALL ANGLE SCATTERING; SPATIAL RESOLUTION; SPIN; SPIN ECHO; SYNCHRONIZATION; TIME-OF-FLIGHT METHOD; WAVELENGTHS

Citation Formats

Sales, Morten, E-mail: lsp260@alumni.ku.dk, Plomp, Jeroen, Bouwman, Wim, Habicht, Klaus, Tremsin, Anton, Strobl, Markus, and European Spallation Source ESS-AB, Science Division, SE-22100 Lund. Wavelength-independent constant period spin-echo modulated small angle neutron scattering. United States: N. p., 2016. Web. doi:10.1063/1.4954727.
Sales, Morten, E-mail: lsp260@alumni.ku.dk, Plomp, Jeroen, Bouwman, Wim, Habicht, Klaus, Tremsin, Anton, Strobl, Markus, & European Spallation Source ESS-AB, Science Division, SE-22100 Lund. Wavelength-independent constant period spin-echo modulated small angle neutron scattering. United States. doi:10.1063/1.4954727.
Sales, Morten, E-mail: lsp260@alumni.ku.dk, Plomp, Jeroen, Bouwman, Wim, Habicht, Klaus, Tremsin, Anton, Strobl, Markus, and European Spallation Source ESS-AB, Science Division, SE-22100 Lund. Wed . "Wavelength-independent constant period spin-echo modulated small angle neutron scattering". United States. doi:10.1063/1.4954727.
@article{osti_22597913,
title = {Wavelength-independent constant period spin-echo modulated small angle neutron scattering},
author = {Sales, Morten, E-mail: lsp260@alumni.ku.dk and Plomp, Jeroen and Bouwman, Wim and Habicht, Klaus and Tremsin, Anton and Strobl, Markus and European Spallation Source ESS-AB, Science Division, SE-22100 Lund},
abstractNote = {Spin-Echo Modulated Small Angle Neutron Scattering (SEMSANS) in Time-of-Flight (ToF) mode has been shown to be a promising technique for measuring (very) small angle neutron scattering (SANS) signals and performing quantitative Dark-Field Imaging (DFI), i.e., SANS with 2D spatial resolution. However, the wavelength dependence of the modulation period in the ToF spin-echo mode has so far limited the useful modulation periods to those resolvable with the limited spatial resolution of the detectors available. Here we present our results of an approach to keep the period of the induced modulation constant for the wavelengths utilised in ToF. This is achieved by ramping the magnetic fields in the coils responsible for creating the spatially modulated beam in synchronisation with the neutron pulse, thus keeping the modulation period constant for all wavelengths. Such a setup enables the decoupling of the spatial detector resolution from the resolution of the modulation period by the use of slits or gratings in analogy to the approach in grating-based neutron DFI.},
doi = {10.1063/1.4954727},
journal = {Review of Scientific Instruments},
number = 6,
volume = 87,
place = {United States},
year = {Wed Jun 15 00:00:00 EDT 2016},
month = {Wed Jun 15 00:00:00 EDT 2016}
}
  • The recently developed magnetic spin-echo small-angle neutron scattering (SANS) technique provides unique information about the distance correlation of the local vector magnetization as a function of the spin-echo length within a magnetic material. The technique probes the magnetic correlations on a length scale from 10 nm up to 10 {mu}m within the bulk of a magnetic material by evaluating the Larmor precession of a polarized neutron beam in a spin-echo setup. The characteristics of the spin-echo SANS technique are discussed and compared to those of the more conventional neutron depolarization technique. Both of these techniques probe the average size ofmore » the magnetic inhomogeneities and the local magnetic texture. The magnetic spin-echo SANS technique gives information on the size distribution of these magnetic inhomogeneities perpendicular to the beam and, in principle, independent on the local magnetic induction. This information is not accessible by the neutron depolarization technique that gives the average size parallel to the beam multiplied with the square of the local magnetic induction. The basic possibilities of the magnetic spin-echo SANS technique are demonstrated by experiments on samples with a strong magnetic texture.« less
  • We present a new instrument for spin echo small angle neutron scattering (SESANS) developed at the Low Energy Neutron Source at Indiana University. A description of the various instrument components is given along with the performance of these components. At the heart of the instrument are a series of resistive coils to encode the neutron trajectory into the neutron polarisation. These are shown to work well over a broad range of neutron wavelengths. Neutron polarisation analysis is accomplished using a continuously operating neutron spin filter polarised by Rb spin-exchange optical pumping of {sup 3}He. We describe the performance of themore » analyser along with a study of the {sup 3}He polarisation stability and its implications for SESANS measurements. Scattering from silica Stöber particles is investigated and agrees with samples run on similar instruments.« less
  • We report that the detailed structural and mechanical properties of a tetraoleoyl cardiolipin (TOCL) bilayer were determined using neutron spin echo (NSE) spectroscopy, small angle neutron and X-ray scattering (SANS and SAXS, respectively), and molecular dynamics (MD) simulations. We used MD simulations to develop a scattering density profile (SDP) model, which was then utilized to jointly refine SANS and SAXS data. In addition to commonly reported lipid bilayer structural parameters, component distributions were obtained, including the volume probability, electron density and neutron scattering length density.
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