Calibration process - Microscope Alignment

In the Microscope Alignment dialog box, several automated calibration processes are shown.

A software wizard will lead you through the calibration process. To start the wizard, select the Acquire > Calibrations... > Microscope Alignment command. Then click the Calibrate... button.

The following processes are available:

•Eucentric Height

•Coma free beam tilt calibration

•Autofocus calibration

•Stigmator calibration

The eucentric height has to be set before any of the calibration processes in the Microscope Alignment dialog box can be carried out.

Carry out all calibration processes shown in the correct order, with the help of the software wizard. You can repeat certain calibration processes at a later time, if required.

Note: The calibrations in the Microscope Alignment dialog box require a part of the sample with many structures and plenty of contrast.

Prerequisites for the calibration processes:

•Valid shading correction images are available and have been activated.

•The transmission electron microscope is in brightfield mode.

•The magnification has been calibrated.

Note: Before performing the calibration processes in the Microscope Alignment tool window, the software automatically sets what is called a restore point. In the Restore Device State dialog box, you can return the microscope to the parameters that were set in the Microscope Alignment dialog box before the calibration processes were performed. You can find more information on this topic here.

Performing the calibration processes

Note: For the Autofocus calibration calibration process, the magnification may not exceed 50000 x.

1.Open the dialog box with the Acquire > Calibrations > Microscope Alignment command.

2.Click the Calibrate... button.

3.Select all check boxes in the Microscope Alignment dialog box.

4.Click the Next > button.

5.Then follow the instructions given you by the software wizard.

Note: If you receive the Stigmator calibration failed! Please make sure that the specimen is always visible and there is enough structure in your specimen. error message or a similar error message during the calibration process, this could be caused by different things:

•Check if this segment of the sample is too thick or does not contain sufficient structures. If necessary, go to another part of the sample or change the value in the Maximum z-range field, in the Acquisition Settings > Acquisition > Autofocus dialog box. You can find more information on this topic here.

•Check if the aperture can be seen the image. If necessary, adjust the aperture.

•Check if the beam is off-centered. If necessary, center the beam.

6.Click the Next > button.

7.The Microscope Alignment - Eucentric Height dialog box appears.

7.Check the live-image and make sure that no disturbing objects are visible.

8.Wait until the Set Eucentric Height button becomes active.

9.Click the Set Eucentric Height button.

•The eucentric height will be set.

10.Then follow the instructions given you by the software wizard.

11.Click the Next > button.

•The Microscope Alignment - Calibrations dialog box appears.

12.Check the live-image and make sure that no disturbing objects are visible.

13.Wait until the Start Calibrations button becomes active.

14.Click the Start Calibrations button.

•The Coma free beam tilt calibration process is carried out.

•The Autofocus calibration process is carried out.

•The Stigmator calibration process is carried out.

•Now the Microscope Alignment - Overview dialog box gives you information about the calibration processes that were carried out. A quality estimation will be given for each calibration.

15.Repeat the respective calibration process if the Poor or Fair entry is displayed in the Quality estimation field.

For example, you can check whether the sample is shown with sufficient contrast or you can try carrying out the calibration process again with a lower magnification.

16.Click the Finish button to close the software wizard.

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