Small/Wide Angle X-ray Scattering (SAXS/WAXS) Ganesha 300XL (SAXSLAB)

The CNIE at UCL has a unique in-house Small/Wide Angle X-ray Scattering (SAXS/WAXS) instrument called Ganesha 300XL. This state-of-the-art SAXS/WAXS is developed by SAXSLAB for CNIE with full motorization, extensive automation, large sample chamber and versatile sample area to provide a highly customised instrument for:

• Ambient work with up to 30 solid samples in a single run
• Temperature dependent analysis between -100 and 350°C
• Solution scattering in refillable capillaries from 4 to 80°C
• GISAXS/GIWAXS Analysis
• Time-resolved Micro-fluidics monitoring in air 
• q range 0.0025Å-1 to 3 Å-1, 2θ range 2° to 60°

SAXS provides essential information on the structure and dynamics of large molecular assemblies (polymers, colloids and porous materials) in various environments. It is a useful complementary technique to study complex systems such as:

• Heterogeneous catalysts and adsorbents
• Membranes, thin films and interfaces
• Polymer processing/design
• Micro- and nano-fluidic systems
• Supramolecular organisation in biological systems
• Self-assembly of mesoscopic metal particles, colloids, liquid crystals and devices
• distribution, adsorption and arrangement of nanoparticles, proteins or surface charges

Application

Ganesha 300XL can be used to evaluate multi-scale structures such as atomic structure (0.2 - 1 nm) and molecular structure (1 nm to 100 nm). The sample-to-detector distance is changeable in less than one minute with full motorization. It's suitable to study materials with different forms including solids (powder, paste, thin film), liquids, liquid-crystals, and gels (with ordered and disordered structures).

Main applications:
1) Nano-particle size, shapes, distribution and polydispersity analyses.
2) Three-dimensional protein molecule structure analyses (folding and unfolding).
3) Identification of molecular assembly or disassembly.
4) Colloids, metals, cement, oil, polymers, plastics, foods and pharmaceuticals.

Sample Preparation

1. Load you sample into a 1.0mm or 1.5mm borosilicate glass capillary
2. Seal the capillary either with a flame, superglue or wax
3. Load the capillary samples into the samples holder, and label the samples with its position in log book, e.g.
0305 - samples A
0306 - samples B
0307 - sample C

Calibration

Silver Behenate (peak at 0.1076 1/Å)
Silver Behenate is the standard for SAXS machines., with a peak in the middle of the traditional SAXS region, a strong scattering pattern and a shelf-life of several years (when kept dry and in the dark). Unfortunately Silver Behenate is NOT the golden standard that one would hope for because: Silver Behenate varies from supplier to supplier; Silver Behenate degrades over time when subjected to air, humidity and/or lightSilver; Behenate often shows peak splitting at higher orders, with peaks separated by about 1.7%. Neverheless a Silver Behenate sample, when regularly refreshed works out as a nice, well accepted standard for many SAXS applications. The SAXS scattering pattern of a standard silver behenate powder sample wrapped in aluminum paper is shown.

Specification

• High Brilliance Microfocus Source
• Motorized Collimation System: consisting of JJ X-Ray high precision 4-blade slits with single crystal low-scatter blades. The continuously variable aperture sizes allow for an unlimited choice of resolution.
• Fully Evacuated Flight Path for minimal scattering
• On-axis sample Viewer
• Large sample area with space for potentially complicated sample environments
• Motorized sample stage with XY motion (for sample placement and multiple sample mounting) combined with a Θ-stage for standard SAXs and GISAXs
• Pilatus 300K Solid-State Photon-Counting Detector providing ultimate noise reduction, high dynamic range, and radiation hardness for long-term maintenance free operation.
• Proprietary Noise-reduction Algorithm to remove cosmic background
• Multiple Insertable Beam stops for different configurations
• Full 3-axis Detector Motion of the detector, achieving sample-to-detector distances between 80 mm and 1450 mm, and allowing for measurement with the beam centred on the detector as well as off-cantered
• Real-time automated Data-Reduction