The JEOL 100CX II TEM  is a traditional transmission electron microscope (TEM) with a tungsten filament. The tungsten electron source is heated to a high temperature, and the energized electrons escape the tungsten metal, are concentrated into a beam, and accelerated down the length of the TEM column.

As the electrons spiral down the column, they are focused by the magnetic field of the electromagnetic lenses and sent through the thin, 100 nm, sample. The magnified image of the specimen is formed on the fluorescent screen by the post-sample electromagnetic lenses of the column. This TEM is equipped with a side-entry goniometer and a side-mount digital camera.


This TEM is used to obtain routine-magnification transmitted electron images of materials, polymers and biological samples.

To reserve time or request training on this tool, click here to go to the JEOL 100CX-II TEM page on SUMS.


Titania particles
TEM image of titania nanoparticles
TEM perlite3
TEM image of silver nanoparticle
Silver nanoparticles that appear blue in visible light
Silver nanoparticles that appear blue in visible light


System Details:

The accelerating voltage is variable: 20, 40, 60, 80, 100 kV

Magnification range 360x-320,000x

Resolution: 2Å (lattice) and 3Å (point to point)

Operation Modes: Bright Field, Dark Field and Diffraction

Single Axis Tilt± 60°


Performance Check Results:
brightfield TEM image of ~5 nm nanoparticles; July 2017
brightfield TEM image of raw carbon ~1- 2 nm January 2018
Camera Calibration Results:


Operating Instructions

Operating Instructions

Initial conditions:

DP light is on, HIGH VACUUM light is on.

Ready indicator light is on.

Objective aperture is out.

SAD aperture is out.

Accel Voltage is off (HT button is out).

Specimen holder is inserted into the goniometer (opening for sample).

Stage drives are centered

Shutter on Auto.


SUMS logged into and activated.


I. Select the accelerating voltage for the sample

Press HT and sequentially increase the accelerating voltage in steps: push in the button for 20kV,

wait for the dark current to stabilize,

push in the button for 40kV, wait for the dark current to stabilize,

push in the button for 60kV, etc.


II. Load your sample into the appropriate sample holder

Remove the sample holder from the goniometer:

Hold the handle protruding from the goniometer and pull straight back

Turn 90o towards you

Ease the holder out by bracing your thumb against the goniometer, and pulling straight back again

Avoid touching the sample holder beyond the o-ring; handle your sample with tweezers. Load a holey carbon grid for checking the alignment of the column.


Rest the loaded sample holder in the airlock until ready to insert.


III. Turn on and increase the current to the filament until the black filament image is visible

The beam will become visible around 6, and the filament image around 7.

Turn the knob slowly and at an even rate.


IV. Align the filament image, if needed

GUN ALIGN TILTS will center the black image with respect to the beam;

GUN ALIGN TRANS will center the filament image and beam assembly on the screen.

Saturate the filament when done with the alignment.


V.  Align the gun and the condenser lensAlign the beam at crossover with the center of the screen (GUN ALIGNMENT: TRANS), spot size 1.

Switch to spot size 3, adjust the CONDENSER knob to crossover,

center the spot with ALIGNMENT: TRANS knobs (on either side of the column)

Switch back to spot size 1, adjust to crossover, and


Repeat until spot centers coincide with the center of the screen.

Pick a spot size to work with, 1 or 2.


VI. Check for condenser astigmatism

If the beam is not round at crossover (the smallest diameter), adjust the COND STIG knobs.


VII. Center the condenser aperture

Spread out the beam on the screen, checking for symmetry in the way it spreads.

If it is asymmetrical, adjust the aperture drives on the condenser aperture housing.


VIII. Insert the sample holder

Turn down the filament emission to 4, check that the stage drives are centered;

pump down the airlock, by pushing the end of the sample rod, straight, toward the column; while the red indicator light is on, the airlock is pumping.

When the light goes out, rotate the holder clockwise, and allow the vacuum to pull in the holder, with your hand still on the handle.

Turn the filament back to saturation



IX.  Check the IMAGE WOBBLER setting

Focus the image on the screen, look for minimum contrast.

Turn on the IMAGE WOBBLER: the image on the screen should remain steady.

If not, use the IMAGE WOBBLER A, B knobs.


X. Specimen Height Adjustment

At 5 Kx, focus a feature near the middle of the viewing screen.

Either disengage the motor, or use the foot pedals to tilt the sample 15o , towards you.

The feature should stay in the middle, if it doesn’t, use the z-adjust knob (located directly under the inserted sample holder) to bring it to center.

Return to 0o , adjust the feature to center with the stage drives, and repeat the above two steps until the feature stays centered.


XI. Check the current center in the objective lens

Focus the specimen at 20Kx.

Center a feature on the screen.

Turn the MED FOCUS knob six clicks to the left.

If the feature has shifted off the center, return it with the ALIGNMENT: TILTS.

Return to focus.

If necessary, center the feature with the stage drives.

Repeat the above procedure until the feature stays centered.


XII. Check the intermediate and projector lens alignment

Center a large feature on the screen at 5 K mag.

Select SA DIFF and camera length 240, or the camera length to be used (60).

Focus the center spot with the small, inner CAMERA LENGTH knob. The feature selected in MAG should be visible in the center spot.

Switch between MAG and SA DIFF.

Check that the feature remains centered in SA DIFF mode. If adjustment is necessary, ask for help.  [Allen wrenches are needed on the intermediate lens (in MAG), located about eye level on the column, and the projector lens (in SA DIFF). Repeat until the feature remains centered in both modes.]


XIII. Voltage centering

Increase the mag to 100K, and center a tiny feature or hole in the center of the screen.

Turn on the HV WOBBLER.

Adjust the ALIGNMENT: TILT knobs until the centered image moves radially, not in any direction.



XIV. Inserting the objective aperture


Rotate the appropriate objective aperture into the path of the beam.

Focus on aperture with diff focus (the small, inner knob of the CAMERA LENGTH knob)

Center the aperture around the beam.

Push MAG.


XV.  Astigmatism Correction

At 100K, center a hole small enough to be seen through the binoculars.

Overfocus the image, to view the dark Fresnel fringe inside the hole.

If the line does not go around the hole symmetrically, adjust the OBJ STIGMATOR FINE knobs.


You’re done! Have a good session!



Session Shut Down:

Turn off the filament emission.

Step the HT down to 20, then shut off HT.

Return spot size knob setting to 1.

Remove objective and/or SAD apertures.

Reduce magnification to 5 K

Center the stage drives (also called specimen translators)

Remove the sample from the specimen holder, and store the holder in the TEM, under vacuum.

Turn off the CCD camera, if it was used.

Log out of SUMS.