Single Channel Waveguide with Roughness

We recently introduced a concept of a neutron waveguide for enhancing the intensity of the evanescent wave inside the sample next to the waveguide. This allows for studying tribology mechanisms of soft matter/solid interfaces using grazing incidence neutron spin echo spectroscopy (GINSES) and small angle neutron scattering (GISANS). In several experiments, the number of layer structures in the waveguide was chosen to be 1 and 3. Both waveguides increased the scattering intensity of GISANS (and GINSES) experiments successfully, while the simpler waveguide produced additional small angle scattering that was not rationalized so far. The roughness on the 100nm and μm length scale may produce additional background at smaller angles. Comparisons are drawn using the Distorted Wave Born Approximation (DWBA), which is especially useful for the roughness discussion.