Examples from the  Monitoring & Maintaining CD

TEM Resolution Test

In order to operate a TEM at high resolution you need to set the instrument up and operate under conditions similar to those listed below,

1. Insert the holey specimen and run the instrument up to the kV that you wish to use, check the emission current is near to a suitable  range recommended for resolution (25 to 35µA) then wait >45 minutes.

2. .Set the specimen at the eucentric height (see Maintenance 1) and expect to use a spot size (probe current) near to or smaller than 60% of the spot size range (i.e. 100% is the smallest spot size). (If the signal is too low at these levels your filament is too far from the cathode aperture, see filament position.)

3. Accurately align the instrument, the gun, the condenser, the condenser aperture, the current or voltage centre, image centre and the objective aperture

4. At double the picture magnification focus and correct the astigmatism for the fringe to be even all round the hole, on a hole near to the area you wish to record.

5. Check the performance by viewing the image down the binocular when supporting your head with your hands, if the performance is not good enough move to another area, re focus and correct the astigmatism. The fringe needs to only just visible, with an over focus condenser lens, for the best resolution.

6. When you are satisfied reduce the magnification and record the image, a through focal series is required.

The CD carry sound, pictures and text with hyperlinks to appropriate pages or pop up text boxes.

Here the link to the cathode assembly reference takes the reader to the cathode assembly and gun components explanation.

For a further example click here