The SWAXS setup has been designed with a focus on hierarchical, wood-based materials; for example, the WAXS detector allows monitoring diffraction from cellulose fibrils/fibers in all directions of the scattering plane, which is instrumental for scanning SWAXS mapping of cellulose fibril orientation. Since many in-situ studies during material processing are foreseen, data acquisition times down to ms regime is possible. Specific equipment are listed below.

Detectors

ForMAX is equipped with two state-of-the-art hybrid pixel detectors: a Dectris EIGER2 X 4M SAXS detector and a custom-designed X-Spectrum Lambda 3M WAXS detector.

DetectorEIGER2 X 4MLambda 3M “windmill”
UsageSAXSWAXS
Number of pixels4M3M
Sensor size (h x v)2068×2162 pixels4x512x1536 pixels
Pixel size (h x v)75×75 µm255×55 µm2
Maximum frame rate500 Hz1 kHz

The SAXS detector is placed on a motorized XYZ trolley inside the SAXS flight tube and can be placed approximately 800 – 7600 mm downstream of the nominal sample position. The figures below show the smallest and largest scattering vector moduli versus x-ray energy for selected sample-to-detector distances (SDD), assuming the x-ray beam impinges in the center of the detector.

Saxs Homepage
Nominal minimum (left) and maximum (right) SAXS q versus x-ray energy for selected sample-to-detector distances.

The WAXS detector is mounted on an evacuated nose cone of the flight tube and the four modules of the WAXS detector have a “windmill” geometry with a hole in the center, to pass through the direct beam and the SAXS signal (see image below). It allows WAXS data collection at scattering angles 2θ=7-20 degrees, in all directions. See table below for details of the detectors.

Waxs Homepage
Left: Cellulose diffraction pattern, measured from a thin piece of oak at 12.7 keV. Right: Nominal accessible WAXS q range (gray area) versus x-ray energy.

Sample manipulation

ForMAX has the following sample stages for different SWAXS experiments:

  • SWAXS: A modular 5-axis stack of sample stages from Huber for general SWAXS experiments. From bottom to top:
    • 2-circle segment (pitch, roll), model 5203.30 (+/- 13 and +/- 12 degrees range for lower and upper axis, respectively)
    • 2-axis horizontal stage, model 5102.25 (+/- 25 mm translation range for each axis)
    • vertical stage, model 5103.A20-40 (+/- 20 mm translation range)
    • optical breadboard on top to facilitate mounting of sample holders or environments
ForMAX_SWAXS_stages
  • Scanning SWAXS imaging:  A modular 5-axis stack of sample stages from Huber for scanning SWAXS experiments. From bottom to top:
    • vertical stage, model 5103.C30 (+/- 10 mm)
    • 2-axis horizontal stage, model 5102.25 (+/- 25 mm translation range for each axis)
    • custom large-range pitch stage, model 5202.80 (+/- 45 degrees)
    • yaw stage, model 408
    • manual 5-axis goniometer head 1002 or 1005 can be mounted on top
    • optional PMMA pins for sample mounting (shown in the mechanical drawing below)
Scwaxs Homepage