Experimental determination of resolution function parameters from small-angle neutron scattering data of a colloidal SiO₂ dispersion

A dilute dispersion of charge-stabilized, monodisperse silica nanoparticles has been used to determine the instrumental resolution function parameters of a conventional small-angle neutron scattering instrument in pinhole geometry over the entire accessible range of momentum transfer q. Independent determination of the structure parameters of the colloidal silica dispersion by small-angle X-ray scattering enables refinement of both the q-independent geometric and the q-dependent (wavelength spread or poly­chromaticity of the neutron beam) contributions to the resolution function. The procedure described is appropriate if no further instrumental characterization is available. It is demonstrated that the sample used for refining the resolution function parameters has to exhibit sharp structural scattering features such as Bragg reflections, form factor maxima and minima, or an inter-particle correlation peak for each instrumental configuration at which the measurements have been performed to cover a q range of two orders of magnitude (0.03 < q < 3.2 nm^-1).