ABSTRACT
Small-angle scattering (SAS) techniques are powerful tools for characterizing complex microstructures and studying porous materials. A. Guinier first published his work on SAS studies in 1937 [7.1]. The fundamentals of SAS for both X-rays and neutrons have been described in detail by A. Guinier and G. Fournet, 1955 [7.2]. Several researchers have developed since then theoretically and experimentally the SAS technique [7.3,7.4,7.5,7.6] and good general introductions on SAS are given in the technical literature [7.7,7.8]. H. Ritter and L. Erich carried out the first small-angle X-ray scattering (SAXS) experiments on porous materials in 1948 [7.9]. The first small-angle neutron scattering (SANS) spectrometers were built in the 1970s in Germany and France. They proved very popular and they were soon built at most neutron scattering centers, including those in the United States. Due to their high cost of operation, the peculiarities of the experimental facilities, and the particular cycle of operation of a neutron source, a SANS experiment needs to be planned carefully and time at the facility be reserved well in advance. In scheduling time for a neutron scattering experiment, a scientist must arrange the most efficient use of the instrument for the benefit of all users.
