HT-HP SAXS – WAXS

Principle :

X-ray diffusion techniques are often used to study the structure of soft matter or nanomaterials, from the nanoscopic scale (WAXS : “Wide-Angle X-ray Scatttering”) to the mesoscopic scale (SAXS : “Small-Angle X-ray Scatttering”). As part of PLANEX Equipex, a commercial experiment has been adapted in order to implement an autoclave with transparent windows. Therefore, this ensemble allows in-situ measurements of sample at high pressure and high temperature.

Scientific value :

As this autoclave is capable of withstanding extreme constraints, similar to the environmental conditions of the superior earth’s crust, it is well suited in a laboratory framework for geological application. As an example, the coupling with WAXS experiment to determine the hydration level of clay as a function of pressure and temperature. In the same way, the combination with SAXS can provide data on the first stages of cristal and bubble nucleation within different kinds of magma.

Development :

The design of this autoclave with transparent windows is based on the one used at the FAME beamline of ESRF, dedicated to X-ray absorption spectroscopy (Testemale et al., 2005 [1]), with the support of Neel Institut and the SERAS.

Experimental conditions :

• Pressure : 1 – 2000 bars
• Temperature : 20 – 1200 °C
• Transparent windows : beryllium (Ø 5 mm)
• Transmission measurement : volumetric analysis
• Nature of sample : solid, liquid, powder
• Dimensions of sample : Ø 1 – 4 mm
• Sample holder materials : vitreous carbon

Technical information :

• Xeuss 2.0 beamline (Xenocs)
• X-ray source Mo (Genix 3D) : E = 17.45 keV (λ = 0.71 A^-1)
• Collimated beam : 0.6 x 0.6 mm² – 8 x 8 mm²
• 2D detector Pilatus3R 0.3 MP (Dectris) : 83.3 x 33.5 mm²
• Sample to detector distance : 20 cm – 2.5 m
• Qmin – Qmax : 5.10^-3 – 5 A^-1
• Data treatment software : Xsact, Foxtrot

X-ray diffusion experiment is in operation and open to users.

Involved collaborators in this experimental development, together with ISTO :