SAXS: Small Angle X-ray Scattering

Small Angle X-ray Scattering (SAXS) is a technique particularly suited for the structural investigation of partially ordered materials, usually applied to condensed matter systems. SAXS provides information about larger scale bulk microstructure within a sample, usually in the size range from approximately ~1nm up to around 300nm.

 The high intensity X-rays available at a synchrotron provide two chief benefits over lab-based instruments.

• Firstly, the greater X-ray intensity allows measurements to be performed at a greater separation between the sample and the detector, which allows access to a much wide range of length scales (particularly for larger length scales) than achievable using a lab instrument.
   
• Secondly, the high intensity of the X-rays at a synchrotron means that measurement times are much faster, allowing structural investigation of non crystalline materials under in situ conditions, for example fluid flow at high pressures and/or temperatures. SAXS at Diamond can provide reliable access to millisecond or shorter time scales, essential for understanding kinetic processes such as ordering and alignment in liquid crystalline materials or microstructural changes during processing. Information can be obtained on the shape and size of particles and macromolecules such as polymers and proteins which may not be possible using other techniques.

SAXS can be applied to systems that are either difficult or impossible to crystallise, may be complex or composite systems or materials with large scale self-organisation. Due to the wide range of sample types, SAXS has been employed in a wide range of applications from drug delivery systems and protein solution shape analysis through to formulations, phase behaviour, catalysis, advanced materials development and engineering.

USAXS is a subset of SAXS and a member of the larger X-ray scattering techniques family. USAXS means Ultra-Small Angle X-ray Sacttering where by the smaller the angle recorded, more information about the larger structure can be determined.