The reflectivity R(Q), was determined using the time-of-flight technique, measuring the momentum transfer normal to the interface, defined as Q = (4π sin θ)/λ, where λ represents the wavelength and θ the grazing angle of incident neutrons. To achieve the broadest Q range and the highest sensitivity to interfacial structure, reflectivity spectra were obtained for various grazing incidence angles, θ. Illumination of the sample was conducted with a resolution of δQ/Q ~7%. The measured reflectivity profiles underwent correction for wavelength-dependent transmission through the silicon substrate. Subsequently, the raw data were normalised and plotted as RQ versus Q to enhance clarity before fitting.