Operating CM12

Chen Xu

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This is a quick check list for the impatient user who already has a basic knowledge of the CM12. It gives the correct steps to align the scope and to set up the conditions for low-dose imaging. A pdf version of this document is also available.

For details on operating the scope and all other information, please refer to the original hard copy of the "Operating Instructions" that came with the scope.

A very brief, "condensed" version of this document can be found on this pdf and on the wall in the CM12 room.

Table of Contents
1 Check log book to see if there have been any problems
2 Check vacuum status
3 Add Liquid Nitrogen to the BIG anti-contaminator dewar
4 Apply High Tension
5 turn filament on
6 Check saturation and gun tilt, and then saturate the filament.
7 Check C2 aperture mechanical position and C2 stigmatism
8 Check specimen holder & load grid
9 Insert specimen holder into column
10 Adjust the specimen height to the eucentric position.
11 Put in objective aperture and center it
12 Check Objective Lens stigmatism
13 Check Pivot X, Y
14 Check voltage and current rotation centers
15 Re-center the objective aperture and check obj. stigmatism again
16 Typical Low-Dose setup parameters
17 Align an identified area under Exposure and Search
18 Check S1 and S2 parameters
19 Check exposure parameters
20 Taking Pictures On Film
21 CLosing Up

1 Check log book to see if there have been any problems

It is always a good idea to check the LOG book. You can find necessary information listed there, such as: