Ultra-high vacuum (UHV) systems are carefully designed to prevent any kind of incursion from the outside. It goes without saying, then, that samples within UHV systems cannot be switched out, rotated, or moved simply by reaching inside.
Instead, the jobs of sample manipulation, positioning and preparation are performed by analytical stages.
The Importance of UHV Systems in Surface Analysis
In order to perform accurate analyses of a surface, it must be atomically clean. This not means ‘clean’ in the conventional sense (free from solid and liquid contamination) but also completely free of gas and vapor molecules that adsorb to surfaces in very thin layers.
These conditions of cleanliness can only be achieved in ultra-high vacuum (UHV) environments, with pressures between 10-5and 10-10 Pa.1,2
UHV technology is vital to surface analysis. Under 'standard' high vacuum (HV) conditions – ranging from 10-1 to 10-5 Pa – a molecule-thick layer of residual gases can cover a surface completely in only a few seconds. At UHV pressures, however, it takes days for the same to occur.
Surface analytical techniques such as low energy electron diffraction (LEED), auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) are dependent on UHV environments which allow photon, electron and ion beams to be transmitted freely for measurement.
Analytical Stages for Surface Analysis
Analytical stages are responsible for manipulating samples inside UHV systems. In addition to the precise positioning of samples, analytical stages can provide additional functionality, including heating, cooling and potential biasing.
Surface science involves the study of processes and phenomena that occur at near-atomic length scales, which places high demands on analytical stages.3,4
As well as providing a high degree of stability, analytical stages for surface science applications must also be capable of precise and versatile positioning.
Many surface techniques also require analytical stages also require temperature control. ‘Cold-stage’ techniques, for example, require low temperatures to enable the study of volatile samples or those which are not solid at room temperature.
Conversely, heated analytical stages may be used to desorb species from sample surfaces.4,5
MultiCentre Analytical Stages
MultiCentre analytical stages were developed specifically to meet the stringent requirements of UHV surface analysis applications.
Offering precise and stable positioning over three linear axes and two rotational axes (polar and azimuthal), these configurable analytical stages also have a unique ability to provide continuous azimuthal rotation.
MultiCentre analytical stages can be modified to include motorization, sample biasing and heating/cooling. MultiCentre stages can be heated up to 1200°C by either e-beam or resistive heating and can be cooled to under 30 K via either liquid helium or liquid nitrogen cooling systems.
To learn more about MultiCentre analytical stages from UHV Design, download the product brochure or contact UHV Design today.
- The Fundamentals of High, Ultra & Extreme High Vacuum.
- What is UHV - Orsay Physics.
- Ebnesajjad, S. Surface and Material Characterization Techniques. in Surface Treatment of Materials for Adhesive Bonding 39–75 (Elsevier, 2014). doi:10.1016/B978-0-323-26435-8.00004-6.
- O’Connor, D. J., Sexton, B. A. & Smart, R. S. C. Surface Analysis Methods in Materials Science. (Springer Science & Business Media, 2013).
- Urquhart, A. J. & Alexander, M. R. Characterisation using X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). in Tissue Engineering Using Ceramics and Polymers 175–203 (Elsevier, 2007). doi:10.1533/9781845693817.1.176.
This information has been sourced, reviewed and adapted from materials provided by UHV DESIGN LTD.
For more information on this source, please visit UHV DESIGN LTD.