New two-dimensional data treatment software for small-angle scattering

A new program is presented which performs data treatment in one, two or three dimensions. While one-dimensional data treatment can be performed easily by many programs (canSAS, EMBL, ISIS, ILL, NIST), few deal efficiently with more dimensions. Indeed, specific attention has to be paid to the selection of the relevant data. Their display and models are relatively complex. This new program has been developed according to the needs of small-angle scattering users, but is not limited to these fields. Its original purpose was to model forward anisotropic scattering and diffuse scattering typically produced by large structures such as polymers, aggregates, self-assembly systems or micellar solutions. It is also suited to modelling Bragg scattering. With time, many filter configurations (rectangles or sectors, with possible symmetries and display along various coordinates) and many model functions (centred or not, possibly with cofactors, with Cartesian, polar, or three-dimensional coordinates) have been added. Models are fitted by the steepest descent model with chi(2) as the minimization function. The software is written in Fortran with the PGPLOT graphics package. It runs with the Windows operating system.