Contact Us

Dr Debbie Hammond d.hammond@sheffield.ac.uk

Prof. Graham Leggett
graham.leggett@shef.ac.uk

Chemistry Department
University of Sheffield
Dainton Building
Brook Hill
Sheffield
S3 7HF

The Kratos Axis Supra X-ray photoelectron spectrometer has some significant enhancements over the Axis Ultra DLD. In particular it is equipped with a gas cluster ion source, a hot and cold stage, and a surface science station as well having improved chemical imaging and UPS facilities.

Supra

Gas Cluster Ion Source: The argon gas cluster ion source can generate both monoatomic Ar+ ions and Ar n+ cluster ions of between 100 to 2500 atoms over a wide range of beam energies (200eV to 20 KeV). The ion energy is shared between all the atoms in the cluster leading to a much reduced partition energy. At these low energies, energy transfer from cluster to material ocurs primarily at the surface - causing far less sub surface damage. The gas cluster ion source is conseqently suitable for the depth profiling of organic material to a depth of 100s of nm, or gentle cleaning of a sample surface prior to UPS analysis.

Chemical Imaging: Parallel imaging with high spatial resolution and high energy resolution is achieved by using a spherical mirror analyser with a delay line detector. The ultimate spatial resolution is <3 microns, with a field of view ranging from 100 microns to 2 mm. The excellent sensitivity of the Supra means chemical images can be collected from organic monolayers. Analysis of images so collected are carried out in CASAxps, for which Sheffield University has a sitewide licence. Small spot analysis, line scans and scanned images from 200 micron to 8 mm are also possible.

Hot and Cold Stage: The hot/cold stage can heat (and hold the temperature) of the sample holder up to 800 deg C or down to less than -100 deg C, either within the flexilock or the sample analysis chamber. This makes it suitable, for example, to fast freeze biological samples on a precooled sample holer for analysis without prior lyophilisation.

Angle Resolved XPS: The Supra software includes a stand alone depth profile reconstruction module which can be used to determine a depth profile from the top 4 to 6nm of a sample using angle resolved x-ray photoelectron spectroscopy.

Surface Science Station: