A treatment of instrumental smearing effects in circularly symmetric small-angle scattering

Instrumental smearing effects can result in a significant deviation of measured small-angle scattering data from the ideal cross section. The effect of various contributions to smearing is described. The case of circularly symmetric scattering measured on an instrument collimated by circular apertures is treated in detail. For such measurements, it is shown how known scattering functions can be smeared to allow estimation of parameters by a fit to the observed data, and also how the indirect Fourier transformation method can be used to desmear the observed scattered intensity.