TY - BOOK

T1 - Development of Instrumentation for Spin-Echo Induced Spatial Beam Modulations

T2 - For Small Angle Scattering Investigations

AU - Sales, Morten

PY - 2015

Y1 - 2015

N2 - Spin-Echo Modulated Small Angle Neutron Scattering in Time-of-Flight mode (ToF SEMSANS) is an emerging technique extending the measurable phase space covered by neutron scattering. Using inclined magnetic field surfaces, (very) small angle scattering from a sample can be mapped into the spin orientation of the neutron as it has been shown in Spin-Echo Small Angle Neutron Scattering (SESANS).Taking this technique further we have shown that it is possible to perform quantitative Dark-Field Imaging, where the small angle scattering signal of individual areas in a neutron image can be obtained. This was done by using triangular shaped magnetic fields to create a spatially modulatedbeam after the spin analyser, and mapping the small angle scattering signal into a dampening of the amplitude of the beam modulation.The first progress we made was to construct the SEMSANS instrument at the Reactor Institute Delft, TUDelft, and resolve the modulation using absorption gratings in front of a detector without spatial resolution, i.e. a simple counting detector. Combining this with a virtual copy of the instrument, built using the Monte Carlo Ray-Tracing simulation package McStas, we were able to expand our investigations beyond the instrumental limitations at the time in order to examine the effect of restoring the SpinEcho condition.

AB - Spin-Echo Modulated Small Angle Neutron Scattering in Time-of-Flight mode (ToF SEMSANS) is an emerging technique extending the measurable phase space covered by neutron scattering. Using inclined magnetic field surfaces, (very) small angle scattering from a sample can be mapped into the spin orientation of the neutron as it has been shown in Spin-Echo Small Angle Neutron Scattering (SESANS).Taking this technique further we have shown that it is possible to perform quantitative Dark-Field Imaging, where the small angle scattering signal of individual areas in a neutron image can be obtained. This was done by using triangular shaped magnetic fields to create a spatially modulatedbeam after the spin analyser, and mapping the small angle scattering signal into a dampening of the amplitude of the beam modulation.The first progress we made was to construct the SEMSANS instrument at the Reactor Institute Delft, TUDelft, and resolve the modulation using absorption gratings in front of a detector without spatial resolution, i.e. a simple counting detector. Combining this with a virtual copy of the instrument, built using the Monte Carlo Ray-Tracing simulation package McStas, we were able to expand our investigations beyond the instrumental limitations at the time in order to examine the effect of restoring the SpinEcho condition.

UR - https://soeg.kb.dk/permalink/45KBDK_KGL/fbp0ps/alma99122849560605763

M3 - Ph.D. thesis

BT - Development of Instrumentation for Spin-Echo Induced Spatial Beam Modulations

PB - The Niels Bohr Institute, Faculty of Science, University of Copenhagen

ER -