Solving the problem of SANS instrument optimization

The problem of the optimization of small-angle neutron scattering instruments installed at steady neutron sources is discussed. The optimum solution is shown to be that in which full use is made of either the available luminous area of the source or the available hall space and not necessarily that corresponding to the equal-flight-paths design. Design criteria and their implementation are discussed taking into account space constraints on the instrument's layout. It is shown that the performance of currently operating SANS facilities can be substantially improved by following the optimization procedure proposed by the authors.