SAXS: Small angle scattering of X rays

(contributed by Arnaud de Geyer, CEA-Grenoble, France)

The shown data corresponds to a SAXS pattern from a phospholipid / water cubic phase. Phospholipids arrange into bilayer in solution in water. Such bilayer (typical thickness 40 Angstroms) extends laterally, thus forming an infinite membrane. In this system, this membrane is regularly curved in space in such a way that it leads to a larger-scale structure that shows cubic symmetry. The series of intensity rings seen in SAXS corresponds to diffraction peaks by this large-scale structure (the unit cell parameter is typically 100 Angstroms). The data shows the results from a 2-dimensional position dependent detector and a series of peaks obtained by radial projection.