Theyencheri Narayanan, ESRF – The European Synchrotron, Grenoble, France

Recent developments in Synchrotron SAXS instrumentation

The advent of third generation synchrotron sources in the mid-nineties led to significant broadening of the scope of small-angle X-ray scattering (SAXS) techniques in structural investigations. The high brilliance of these sources implying high photon flux and fine collimation made SAXS a unique scattering method in terms of angular and time resolution, and small sample volumes [1]. As a result, time-resolved experiments down to the millisecond range became feasible even with dilute and low contrast samples. Similarly, micrometer beam SAXS enabled the investigation of tiny specimen and scanning the local microstructure in hierarchical materials. The present capabilities of SAXS methods are due to a combination of not only the development of instrumentation but also the advances in data analysis methods. In particular, modern detectors and sample environments together with high level of automation have dramatically increased the throughput of SAXS experiments. Advanced modelling and simulations can provide very quantitative structural and kinetic information. This presentation will give an overview of some of the recent applications in the investigation of structure and dynamics of soft matter and related biological systems [1]. Advanced SAXS methods allow simultaneous access to a broad range of size and time scales deciphering the structural information from sub-nm to micron ranges and kinetics down to the sub-millisecond range in hierarchically organized systems. Applications range from soft matter self-assembly to cellular processes from nanometer to micron scales.

Finally, some new possibilities offered by the fourth generation sources such as the ESRF-Extremely Brilliant Source will be discussed. The order of magnitude increase in the brightness and degree of coherence are likely to open new avenues in the investigation of soft matter and biological systems by scattering methods.  In particular, the X-ray photon correlation spectroscopy is expected to take a major leap forward. As a result, the equilibrium dynamics over a broader time and length scales will become accessible by this method.  The larger transverse coherence length should also increase the information content in the scattering data which should make the phase retrieval more robust.

References
[1] T. Narayanan, H. Wacklin, O. Konovalov, and R. Lund, Cryst. Rev., 23, 160–226, (2017).

 
The lecture is part of the symposium Recent progress in small-angle scattering from soft matter and biological systems on the occasion of Professor Jan Skov Pedersen's 60th birthday.