Synchrotron Small-Angle Scattering in Brazil

Andre Naudon and friends study the small angles at the poster session in Campinas.

The X Int'l Conf. on Small-Angle Scattering held in Campinas, Sao Paulo, Brazil was organized by A. Craievich at the first synchrotron radiation facility in the southern hemisphere. The field of small-angle scattering continues to develop very rapidly, both in the extension of the scientific fields covered and in the depth of the theory and analysis. Impressive results were presented on the simultaneous use of wide and small angle techniques including time-resolved experiments of X-ray scattering during a crystallization process. Better understanding of the structure of microemulsions, bicontinuous and lamellar phases, were attributed to improvements in the theory of data analysis. The use of perfect-crystal cameras allows high resolution measurements where a large flux is available. Generalized use of high-definition two-dimensional detectors provides better data on poorly-ordered materials and liquid crystals. Small-angle scattering is probably the dominant technique used to study associating polymers, block copolymers and gels. The high flux of synchrotron sources and fine focus permit the use of very tiny samples to study the structure, conformation and dynamics of biologically active molecules. SAS applications to Solid State Physics and Biology that were presented included time-resolved experiments on super alloys, nanocrystalline material characterization and the use of X-ray standing waves for investigations of thin films. The conference was attended by 220 scientists, from 25 countries. 90 manuscripts will appear in Proceedings of the Conference, to be published by Journal of Applied Crystallography. At a satellite Workshop on Instrumentation and Industrial Applications, new developments in neutron SAS sources, and status reports on beamlines and detectors were presented. Talks on industrial applications dealt with the use of large academic facilities and applications such as on-line characterization of fiber processing. A visit to the new synchrotron radiation facility at the LNLS, Campinas, showed that new and original technical ideas are under development in Brazil. The next Int'l Conf. on Small-Angle Scattering will be held at the Nat'l Synchrotron Light Source, Brookhaven, USA, in 1999.