Compucentric Stage

All TESCAN microscopes are fitted with a 5-axis Compucentric stage. A Compucentric stage is designed to preserve the region of interest (ROI) focused and in the field of view after rotating and tilting the sample.
This implies that after every rotation or tilting, the stage control system automatically adjusts the Y/Z coordinates in order to compensate for any shift or loss of focus of the ROI occurred in the process. Thus, the user does not need to worry or make extra efforts in manipulating the specimen since the ROI is always preserved and focused after every stage operation. In addition, the Compucentric stage does not introduce any limitation on samples thus making the microscopes really versatile. 

Key features

  • 5-axis fully motorised: X,Y, Z, Rotation, Tilting
  • Eucentric tilt and rotation (ROI is preserved in the field of view and focused)
  • Possible to use different sample holders without sacrificing tilt-Eucentricity
  • No limitations on specimen size and height
  • Fast and easy to operate (advantage when used by novice users)
  • Robust stage with maximum sample weight bearing up to 8 Kg (depending on chamber size configuration)

Tilting and Rotating Samples

In general, the ROI is shifted or defocused, or both after a tilting or rotating the sample. This happens every time when the sample is tilted or rotated about an axis that does not coincide with the ROI (i.e. no tilt-eucentric). This in practice is really inconvenient since the user needs to refocus and shift back the sample in order to recover the view of the ROI.

​Compucentric Stage

A 5-axis Compucentric fully motorised sample stage as mentioned before keeps the ROI in the field of view and well-focused after both tilting and rotations. As opposed to an Eucentric stage, a Compucentric stage is much more versatile and easy to use due to the computerised movements which in addition, provides extra features that are either not available in Eucentric stages or require additional efforts from the user to achieve the same operation. 

Compucentric Stage
Compucentric sample stage in MIRA3

Compucentric stage

  • On the Compucentric stage the tilting axis is not on the plane of the sample surface and, as a consequence, the ROI is shifted. The stage control system automatically computes the Z and Y shifts and quickly repositions the stage thus the ROI is brought back to the view of field.
  • The Compucentric stage contains basically two technologies: Eucentric tilt and computer extended range of Eucentric tilt and computer-controlled Eucentric rotation.
  • A Compucentric stage does not introduce any restriction on sample height. Thus, samples with arbitrary topography can be analysed or routine analysis of samples with different heights can be performed without any limitations.
  • A Compucentric stage makes your microscope truly versatile.
  • Fast and easy to use, a feature which is especially useful for unexperienced users and saving time in analysis.
  • The TESCAN Compucentric stages are configured with different range movements depending on the chamber size. Besides, the stages are robust and can bear samples up to 8 kg depending on the microscope chamber configuration.
  • Different sample holders can be used without scarifying tilt-Eucentricity.
  • Good repeatability especially after long displacements. 

Eucentric stage

  • On an Eucentric stage, the sample is first brought to the eucentric point (where the tilt axis and the electron beam axis intersect – the sample is focused at this point) and then tilted; in this way, the ROI is preserved and kept focused (with limitations, see below).
  • However, from this, we can immediately see that when using an Eucentric stage one can run into problems when dealing with tall samples or certain topographic samples in which one of the features height is such that the eucentric point cannot be reached.
  • Thus, the Eucentric stage restricts the type of samples that can be analysed in the microscope and sets a limitation on sample height.
  • The user needs to set up the position of the sample (Z’) very precisely – which is time-consuming and not an easy task – otherwise it is not possible to have Eucentricity of the stage.  
  • For the same reason, there is a limitation on the type of sample holders that can be used.
  • Mechanical accuracy of Eucentric stages must be preserved to assure good functioning – which is again, not an easy task. 

Whether the microscope is aimed at routine analysis of samples with the same features (which might be the case of industrial applications) or diverse analyses of different type of samples (that also differ in height and size) in a multi-user lab or multidisciplinary institution, the Compucentric stage is the essential component in your microscope that will guarantee meeting your particular analytical needs.