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Modern aspects of small-angle scattering

[Scattering meeting] Attendees at the Small-Angle Scattering meeting. (Courtesy H. Brumberger)
On May 12-22, 1993, a NATO Advanced Study Inst. on 'Modern Aspects of Small-Angle Scattering' took place at the Centro di Cultura Scientifica 'A. Volta,' Villa Olmo, Como, Italy. Lectures and workshops dealt with the following topics: a review of classical small-angle scattering (SAS) theory and newer theoretical developments such as scattering from fractal systems (P.W. Schmidt, MO, USA); modern methods of SAS data analysis (0. Glatter, Graz); information theory and SAS (V. Luzzati, Gif-sur-Yvette); a comparative survey of current SAS instrumentation, including laboratory and synchrotron X-ray sources, neutron sources, and a variety of optical configurations and detector systems (J. Skov Pedersen, Riso); and new experimental developments in contrast variation techniques (H. Stuhrmann, GKSS Forschungszentrum), anomalous scattering, and grazing incidence scattering for observing surface structures (A. Naudon, Poitiers). These presentations were followed by lectures and workshop sessions covering state-of-the-art applications in biology and materials science. SAS studies of phase separation and defect agglomeration in metals and alloys were discussed by G. Kostorz (Zurich) on the basis of several examples, such as the Ni-Al-Mo system. SAS of polymers in solution, with special emphasis on flow systems which yield information about dynamic properties of macromolecules (P. Lindner, Grenoble), and of polymers in bulk (A. Rennie, Cambridge) were extensively discussed, with particular care given to the experimental aspects and to details of data reduction. The small-angle scattering of complex fluids - microemulsions, concentrated colloidal dispersions of interacting particles, etc. - was the subject of a lecture and workshop by E. Kaler (DE, USA). Porosity analysis of ceramic systems, such as polymeric solids formed from silicate precursors, was presented by D.W. Schaefer (Sandia), and SAS of heterogeneous catalysts by H. Brumbergcr (NY, USA).

Biological systems received much attention, since SAS methods, especially neutron small-angle scattering using so-called 'label triangulation, for example, can resolve the well defined internal components - proteins, nucleic acid chains, etc., within complex particles such as ribosomes (R. May, Grenoble). Lipids, lipoproteins, and membranes have been objects of SAS investigations for some time, and continue to be challenging systems. The cubic phases of lipid-containing systems (V. Luzzati), and the structure and dynamics of lipoproteins were the subjects of several lectures and a workshop (P. Laggner, Graz). A final lecture dealt with the complementary methods of static and dynamic light scattering (0. Glatter). A highlight of the meeting was an informal and most enjoyable talk by Prof. A. Guinier about his pioneering small-angle scattering investigations 50 years ago.

The meeting was sponsored by the Scientific Affairs Div. of the North Atlantic Treaty Organization. A. Paar K.G., Graz M. Braun-Graz Optical Systems, US National Science Fndn., and the Intl. Science Fndn. assisted individual students.

H. Brumberger Syracuse U. (USA)