The GSAS package from Los Alamos is a complete crystallographic package allowing use of all types of neutron and x-ray data, from both powders and single-crystals. However, many potential users feel thas GSAS and ‘user friendly” do not belong in the same title. The EXPGUI package was developed as a GSAS add-on to provide an easy-to-learn graphical user interface to some of the more commonly used capabilities of GSAS, while also providing more experienced users with short-cuts, abilities and tools that are not contained in GSAS. EXPGUI and GSAS now have a wide user base. EXPGUI is cited on average one a week and one recent survey found that 70% of Rietveld users across world use EXPGUI and GSAS.
NIST, Gaithersburg, MD, USA