Instruments

X-ray computed tomography (X-ray CT) is a non-destructive 3D imaging technique which allows the subsurface and internal investigation of objects. The technique obtains digital information of 3D geometries and properties based on density differences within the object, which is related to the way in which X-rays are either absorbed or scattered as they pass through. In recent years this technique has become a staple investigation tool in materials science as well as in other fields (biological, geological, industrial).


The University of Sheffield has a ZEISS Xradia 620 Versa X-ray microscope (XRM), the most advanced model in the ZEISS Xradia Versa family and the first such instrument for research purposes in the UK (as of July 2020). Building on industry-leading resolution and contrast, the 620 Versa extends the boundaries of non-destructive imaging for maximum flexibility to accelerate your research.


Innovations in source and optics technology provide higher X-ray flux (25W in the 600 series compared with 10W in the 500 Versa series) to deliver faster tomography scans without sacrificing resolution and contrast. Innovative acquisition workflows allow you to seek—and find—regions of interest at highest resolution without cutting the sample through the Scout and Zoom feature.


The Versa 620 combines both geometric and optical magnification and is equipped with optical lenses (0.4x, 4x, 20x, 40x) to push the limits of magnification and resolution. This allows a minimum spatial resolution of 0.5µm and voxel size of 40nm for high resolution scanning and analysis.


As well as standard 3D imaging, the Versa 620 at Sheffield can be used to non-destructively characterize the 3D microstructure of materials in controlled environments (in situ) as well as to observe the evolution of structures over time (4D). By leveraging Resolution at a Distance (RaaD) capability, the 620 Versa maintains the highest resolution across large working distances, accommodating samples contained within environmental chambers and high precision in situ load rigs.

Image courtesy of Zeiss Microscopy

620 Versa technical specifications & in-situ testing capabilities

  • Location: LG48, Kroto Research Institute

  • Transmission source, tungsten target

  • Spatial resolution: 0.5µm (using 40x magnification)

  • Minimum voxel size: ~40nm (using 40x magnification)

  • Source voltage range: 30-160kV

  • Source max output: 25W

  • Max sample size: 150mm

  • Max sample weight: 25kg

  • Sample stage travel (x, y, z): 50, 100, 50mm

  • Detector: 2000 x 2000 pixel 16bit CCD digital camera

  • Objective lenses: 0.4x, 4x, 20x, 40x

  • Automatic Filter Changer (AFC): includes calcium fluoride, glass, copper alloy, tungsten filters

  • Geometric and optical magnification systems

  • Absorption and propagation phase contrast modes

  • Scout and Zoom functionality: Create high resolution subsurface targeted regions of interest without cutting your sample

  • Other features: Vertical stitch, XRM python API, high aspect ratio tomography (HART), dual scan contrast visualiser (DSCoVer).


Further information can be found here.

In-situ mechanical testing and 4D capabilities:

In situ rigs available:

Deben CT500N-L in situ load stage

  • Integrated tensile & compression testing solution

  • Provides information relating to how the properties of materials/composites change under different loading conditions

  • Up to 500N load

  • Utilises MICROTEST tensile stage control software


Deben in-situ CT5000N TEC load stage

  • Integrated tensile & compression testing solution

  • Has heated and cooled jaws for temperature testing - range between -20°C to 160°C

  • Liquid and electrical stage

  • Up to 5000N load

  • Utilises MICROTEST tensile stage control software


Deben Environmental/Electrochemical cell (custom built)

  • Currently being manufactured by Deben, but will enable in-situ electrochemical experiments for things like fuel cells and corrosion studies

Further information can be found here.