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.affiliation: Nano-Science Center, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Sales
authors.affiliation: Faculty of Applied Sciences, Delft University of Technology, 2629 JB Delft, The Netherlands.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Plomp
authors.affiliation: Helmholtz-Zentrum Berlin für Materialen und Energie GmbH, D-14109 Berlin, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Habicht
authors.affiliation: Space Sciences Laboratory, University of California at Berkeley, Berkeley, California 94720, USA.
authors.forename: Anton
authors.initials: A
authors.lastname: Tremsin
authors.affiliation: Faculty of Applied Sciences, Delft University of Technology, 2629 JB Delft, The Netherlands.
authors.forename: Wim
authors.initials: W
authors.lastname: Bouwman
authors.affiliation: Nano-Science Center, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark.
authors.forename: Markus
authors.initials: M
authors.lastname: Strobl