DEMUX/MUX: removal of multiple scattering from small-angle data

With DEMUX and MUX, a pair of subroutines is provided that allows for the straightforward removal of multiple scattering from small-angle scattering data (DEMUX) or the simulation of the effect of multiple scattering (MUX). The data may be given in an arbitrary scaling. The parameter that must be given to fix the amount of multiple scattering is the transmission reduction of the sample due to small-angle scattering. The algorithm used is based on the method of Schelten & Schmatz [J. Appl. Cryst. (1980), 13, 385-390]. It is valid for a plane flat sample exhibiting scattering of significant intensity at small angles only.