Kratos Axis Supra
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.
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 occurs primarily at the surface - causing far less sub surface damage. The gas cluster ion source is consequently 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.
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 collected are carried out in CASAxps, for which the University of Sheffield 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 degrees C or down to less than -100 degrees 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 holder 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.