Image Core Facility -
CM12 Cryoelectron Microscope
This is our Philips CM12
cryoelectron microscope for routine use, which operates at 120
kV and is used for surveying crystallization trials and frozen-hydrated
samples to be used for structure determination. The intensified
TV camera from Gatan Corp. is
convenient for a group of people viewing the speciman, or, when
coupled to a frame-grabber (Data Translation 3152), for obtaining
an instant image using ImageTool.
This image can be Fourier transformed with Photoshop
plugins to check resolution or defocus levels, or
simply be archived in one's lab notebook.
One of the major characteristics of this CM microscope is that
it has a control panel (the majority is located to the right of
the column and a few to the left below the TV screen) significantly
different from that commonly used in transmission electron microscopy.
The rationalisation of the control components has led to a significantly
reduced number of controls. All details can be found in Philips
Operating Instructions for CM12 Electron Microscope (Doc# PW6030),
a copy of which is on the shelve in Room EM2.
Main Features of the Microscope
High Tension |
20, 40, 60, 80, 100, and 120kV |
Emission Current |
0 - 100uA |
TEM Magnification |
50 - 750,000x |
Ratios of Mag. Values |
1.000(Film), 0.888(Main-Screen),
0.560(Small-Screen), 0.313(35mm Camera), vary with camera
and screen size(TV) |
Camera Lengths |
25 - 6,500mm in 16 steps |
Max. Diff. Angle
(+/-º-SA diaphragm in um) |
10º-none, 8º-800, 5º-200,
3º-50, 2º-15 |
Focussing (in 9 steps) |
0.3um-10mm(LM Range), 3nm-100nm(M/SA
Range) |
Spot Sizes |
10um-200nm(LM Mode), 2.0um-40nm(Microprobe),
100nm-2nm(Nanoprobe) |
Goniometer Tilt Angle |
+/-45º |
Specimen Movement |
2mm in two perpendicular directions |
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