Updated on April 16, 2013

Transmission Electron Microscope




    Starting Up:

    Mounting a Specimen:

    Imaging (standard mode):




tem controls

Two functions: Normalize lenses (when screen is down), i.e. demagnetizes the lenses and then re-sets the lenses to previous settings; Take photos (when screen is up).

Do nothing on CM10 because CM10 has no motorized goniometer.

Turn it to change the holder (must step down on the foot peddle).

(4) RST (RESET) button
Beam intensity control; Bring spot light together [Bring intensity to SHIFT (location of spot)].

(5) FINE
Press it (green light above the button is illuminated) to finely adjust the intensity.

Increases or decreases the brightness (intensity) of the electron beam (via Condenser current).

(7) WBL (Wobble)
Used to adjust the focus by splitting the image into two. Help focus at low magnifications. When the focus is correct, the 2 images overlap, otherwise the 2 images separate.
MULTIFUNCTION  X (ROTATION) can be used to change the orientation (i.e. direction) of the separation between the 2 images.
MULTIFUNCTION  Y (ANGLE) can be used to change the degree of wobble (i.e. how far the 2 images separate at a given degree of de-focus). This increases the angle of the wobble i.e. the angle with respect to the lower objective lens. Too large an angle (i.e. too great a wobble) can result in a lose of the beam.

(8)/(11) Dials to move the sample
When looking for a section of a specific feature, search systematically by scanning back and forth. Be very careful NOT to keep turning either handle if it sticks (i.e. resists turning; a red light should come on): continuing to turn either handle can result in a serious jam and require a service!

TEM image appears on this screen. The 4 corners drawn on in black (eye bow-like) mark the edge of the area exposure to film. Note that a photography record (magnification, plate#) will partially block the top edge, too.

(10) Oculars
A miniature screen, displaying a small, central, region of the image, can be viewed through the oculars. The oculars can be adjusted for individual user’s eyes in terms of focus and distance between the oculars.

(11)/(8) Dials to move the sample.

Turn the knob to increase/decrease the brightness of data screen.

Push the knob to illuminate panel and monitor.

Number 1-11. Lower numbers = smaller spot size (finer beam). 2 is common, 3-4 for high resolution.

(15) FOCUS
Focusing moves the plane of focus up and down. This up and down movement can be accomplished in steps of various sizes, 1 to 9. Step 1 is the smallest and step 9 is the largest.

(16) Date Screen (aka Monitor CRT)
Display vital information about the microscope, e.g. Magnification; Step size; Photograph number etc.

(17) RESET key
Used to clear the ERROR message on screen; or reset quantities such as the number of exposures remaining after changing the film.

(18) READY key
¬Used to move from one screen to another.

(19) AUTO focus
A focus pre-set. If goniometer sample height is correct pushing it places the sample at the correct focal level.

(20)/(21) SHIFT X/Y
X: moves beam in X direction; Y: moves beam in Y direction

(22) D (Diffraction)
Bring the beam down to a spot on the screen. The images generated are of the diffracted beam, not the sample, a technique for material science. We use the Diffraction control for objective aperture (lower, at the same level as the sample holder). Under this control, the magnification controls the “theoretical distance” from the sample to the screen.

Both the inner and outer knobs control the magnification in discrete “jumps”. The image may rotate as magnification is changed.

Function after the activation of ALG, STG, DF, etc. X = beam/image ROTATION (change the magnification to unkown XXX); Y = beam/image ANGLE.

Show the Filament current (good value is 8-10uA). If, after turning up the FILAMENT knob (28) until a beeping sound is heard, the emission is still zero, this could be indication a burnt out filament.

Push to trun on the high voltage.

Turn it slowly to saturate the filament brightness. There is a limit on how high the current should be set at certain parameters. It is NOT necessary to turn down the filament before turning off the HT.

(29) ON
Push it to turn on the entire TEM--restore everything including computer and microscope. Keep it as is.

Turn off the functions that require the cooling water and compressed air. The TEM uses much less electricity under this setting, i.e. during construction or water/electricity power interruption, or for long-term shut down. NOT for normal overnight resting state.

(31) OFF
Push it to shut down the entire TEM. Never do it without administrator’s permission.

(32)/(33) VACUUM ON/OFF
Selecting ON or OFF will result in the pumps being connected or disconnected from the column, but NOT for IGP pump.

(34) Vacuum indicating LEDs for UHV/ HIVAC/PREVAC
Indicate the vacuum condition. The TEM would work only at the condition of both UHV and HIVAC are illuminated. Some features in the vacuum system include (can be seen on Vacuum pages):
    P1 = buffer tank (30-38).
    P2 = rotary pump (pre-pump) (could be 100, but must be down when the VAC is ON).
    P3 = oil diffusion pump (~30, should be below 60, may reach 100 when the film is changed).
    IGP= Ion Getter Pump (~10-20, should be below 52, may reach higher when column is aired).
    Cam Air (Camera Air) for changing plates.
    Col Air (Column Air) for changing the filament.
    Vacuum accidents can be caused by forcing the sample into the column before the red light goes off, or by lower compressor air, etc.

(35) STG (Stigmator)
Is a device use to correct asymmetries in an electron lens by superposing on the field of the lens a second adjustable field. Used to correct astigmatisms.

(36) DF (Dark Field)
Tilt the beam through the specimen. This channel is useful for immunogold TEM and crystal TEM etc.

(37) ALGN (Alignment)
Put the TEM in alignment mode. To be used after changing the filament etc.

(38)  Main/small screen lever
Main screen lever can raise main screen out of the beam for photographing; Small screen lever moves the small screen into the beam for finer focus.

(39)  Center beam-stop insertion
This knob brings the beam stop into position to intercept the cental beam of a diffraction pattern. To operate, turn the knob 45o CCW and push it as far as it will go. The beam-stop is also useful for focussing the binoculars on the small screen (focus on the sharp shadow). The part under it is an adjuster knob (rotation of this knob adjusst the length of tavel of the beam-stop).

(40a)/(41a) Objective/C2 aperture displacement lever
Displace the aperture holder into (rotate to the left) and out of (rotate to the right) the beam.

(40b/d)/(41b/d) Objective/C2 aperture centering control
These knurled knobs operate in two perpendicular directions to center the aperture with respect to the microscope axis. Caution: Do not try to force the control beyond stops.

(40c)/(41c) Objective/C2 aperture selector
This has 4 click stop positions. In each position, one of the 4 apertures held in the holder is positioned on the microscope axis.

(40e)/(41e) Objective/C2 aperture holder
Contain 4 apertures which can be introduced successively into the beam using the selector. The holder can be removed from column (once air has been admitted) by first unscrewing the knurled end and then carefully pulling it straight out. When replacing back ensure that the guide pin enters the slot.

(42)  Specimen holder
Insertion of the holder has tow phases: The first to initiate automatic pumping of the airlock to pre-pump, the second to place the specimen on the electron optical axis. Caution: not lbe left too long in the intermediate position; take care to maintain a firm grip--not let it suck in quickly.

(43)  Airlock indicator light
When lit (red), indicates pre-vacuum pumping of specimen airlock in progress after first stage of insertion of specimen holder. The light extinguishes in 32 seconds then gives clearance for the completion of the insertion procedure which must be carried out right away..

(44)  Gun-lifting level
Lift the gun assembly from the emission chamber (once air has been admitted).

(45)  Emission chamber

(46) RESTART (a tiny button on the left of the screen, not visible in image above)
Never touch it. Press ONLY on instructions of FEI Specialists. Pressing it will restart the computer (leading to a minimum 30 min down time).