The International Conference on Small‐Angle Scattering – past and future

Institute of Physics, University of Sa Äo Paulo, CP 66318, CEP05315 Sa Äo Paulo SP, Brazil The International Conference on Small-Angle Scattering (SAS) is a periodic event that gathers scientists from many areas, including materials science, physics, chemistry and biology. They work on applications of X-ray and neutron small-angle scattering to a variety of nanostructured materials, such as alloys, polymers, glasses, proteins in solution, membranes, liquid crystals, porous solids and nanohybrid systems. Without any doubt, SAS is the most widely used technique for structural characterization of heterogeneous materials on the scale from 1 to 100 nm. At SAS conferences, besides the applications to a variety of materials, new developments of related instrumentation, theoretical analysis and data treatment are discussed. An increasing number of presentations in recent SAS conferences have also dealt with industrial applications. In 1965, the ®rst SAS conference was held in Syracuse in the State of New York in the USA. It was chaired by the late Professor Harry Brumberger. Since then, 12 conferences have been held in different countries, eight in Europe, three in North America, and one in South America. The XIIIth conference will be held in Himeji, Japan. The locations, dates and chairmen of the past 12 conferences, together with some information related to the published proceedings, are listed in Table 1. The proceedings of the ®rst conference were published as a book, and eight of the others in archival scienti®c journals. Apart from the conferences held in 1987 and 1993, the proceedings of the ®ve others were published in the Journal of Applied Crystallography. The numbers of communications presented at the different SAS conferences are plotted in Fig. 1. These numbers follow a monotonically growing function, except between the conferences held in Berlin and Hamburg in 1980 and 1984, respectively. The purpose of this note is threefold: to begin with, it represents a modest contribution to the preservation of the history of the SAS conferences; secondly, it describes some features of its current organization; and thirdly, it is an attempt to explain the clear `kink' or discontinuity in the function describing the number of communications between 1980 and 1984, and the high (exponential) growth rate from 1984 until now, both effects being clearly apparent in Fig. 1. No formal scienti®c association has continuously participated in the organization of SAS conferences. In practice, the location of each event was selected among submitted proposals by the participants of the preceding conference, after a preliminary discussion among the members of the International Advisory Board. Complete responsibility for the practical organization pertains to the Chairman and the Local Organizing Committee. The International Advisory Board helps the local organizers to set up the scienti®c program. This rather informal style of organization is not ideal for maintaining an updated record of the events. In this respect, some coordination of the sequence of conferences by a formal and well-established scienti®c association would seem to be useful. On the other hand, the good quality of current SAS conferences is clearly appreciated by the community, as demonstrated by the fast increase in the number of participants from 1984 until now, and these positive aspects should be preserved. Many participants see the current SAS conferences as a very motivating forum for interesting and friendly discussions. This positive opinion of the SAS community is re ̄ected in the vigorous growth of the number of communications over the past two decades (see Fig. 1). The current ̄exible organizational structure is desirable, as the program may thus be de®ned each time by a different group of scientists from different countries, taking into account a range of independent and usually complementary views. Since the local organizers are currently totally responsible for the event, they usually stress particular aspects of SAS science that may be of special interest to their own community. Indeed, that is precisely what happened with the Xth SAS conference organized in Campinas/ Brazil in 1996. My Brazilian colleagues and I focused on the use of synchrotron radiation and the development of related instrumentation and industrial applications. This was a Aldo F. Craievich