Spring 2003
Professor M.A. Crimp
3513 EB, 355-0294, crimp@egr.msu.edu

Prerequisites: X-ray diffraction, crystallography

Text: D.B. Williams and C.B. Carter, Transmission Electron Microscopy: A Textbook for Materials Science, Plenum Publishing, 1996.

Other References:

M. Von Heimendahl, Electron Microscopy of Materials: An Introduction, Academic Press, 1980.

J.W. Edington, Practical Electron Microscopy in Materials Science, Phillips, 1974.

Thomas and Goringe, Transmission Electron Microscopy of Materials, J. Wiley Publishing, 1979. Reprinted by TechBooks.

Hirsch, Howie, Nicholson, Pashley and Whelan, Electron Microscopy of Thin Crystals, Krieger Publishing, 1965, 1977.

M.H. Loretto, Electron Beam Analysis of Materials, Chapman and Hall Publishing, 1984.

Grading:

1st exam................... 20%
2nd exam.................. 20%
Final exam................ 25%
Lab reports............... 20%
Project...................... 15%

Course outline:

I. Electron optics
II. Electron diffraction
III. Sample preparation
IV. Kinematical theory of image contrast
V. Dynamical theory of image contrast
VI. Weak Beam Microscopy

---

H-800 Operation and Alignment

No food or drink is allowed in the microscope room or the darkroom. Persons who ignore this policy will loose access to the facilities.

Note: The magnifications given in this document are only suggestions. Use magnifications as appropriate and convenient.

Start-up from complete shut down: Begin here

1) Turn on cooling water chiller.

2) Turn on main power connection at wall.

3) Turn on EVAC power switch.
Gun, column and camera switches should be in EVAC positions.
Microscope will pump down in 20 to 30 min.

Start-up from stand-by: Begin here

Application of High Voltage

1) Turn on COL switch.

2) Check the vacuum state (GUN, COL, CAMERA: Green/ SPEC: Yellow).

3) Turn on vacuum gauge and power filament switch.

4) Fill liquid nitrogen cold traps (in front and back of column).

5) Depress the READY/OFF button on the left main panel.

6) Depress the desired accelerating voltage by pressing the appropriate button.

7) Check the HV/BEAM meter to see if the accelerating voltage is properly applied.

Start-up from standby with HT on: Begin here

Filament Saturation and Gun alignment

1) Switch to SA mode from ZOOM mode.

2) Remove all apertures to fully out position.

3) Turn the FILAMENT control knob clockwise while watching the HV/BEAM meter. Stop turning when the beam current is 10 ?A. 1 division is equal to 10 ?A.

4) Set the magnification to 1,000X using the MAG control keys on the left main panel.

5) Center the beam using the BRIGHTNESS CENTERING (deflectors) control on the right panel.

6) Set the spot size to 3 or 5 ?m and leave spot size visible.

7) Insert the #1 condenser aperture (top aperture).

8) Focus the beam using the BRIGHTNESS (C2) control.

9) Decrease the FILAMENT current control to obtain a slightly under-saturated image of the filament (donut shape).

10) Adjust GUN TILT controls to get a sharp, bright & symmetrical image.

11) Set spot size to 1 ?m, focus beam to a spot using BRIGHTNESS (C2) control, and center image using BRIGHTNESS CENTERING controls.

12) Set spot size to 5 ?m, refocus beam using the BRIGHTNESS (C2), and center image using GUN HORIZ controls.

13) Iterate between 11 and 12 until image remains centered. Choose desired spot size (usually 5 ?m).

14) Turn up FILAMENT control knob until the beam current reaches 10 ?A. This should result in a nearly saturated image.

Condenser Aperture Alignment (10,000X)

1) Insert the desired condenser aperture if not already in place.

2) Focus the illumination with the BRIGHTNESS (C2) control and center the image with the BRIGHTNESS CENTERING controls.

3) Defocus the illumination to fill the screen. Center this illumination by manipulation the X and Y alignment controls of the aperture.

4) Refocus the illumination and re-center using the BRIGHTNESS CENTERING controls.

5) Repeat steps 2-4 until the beam expand and contracts symmetrically around the center of the screen.

Condenser Lens Astigmatism Correction (10,000X)

1) Focus the illumination using the BRIGHTNESS control.

2) Make the image as circular as possible by adjusting the COND STIGM controls on the lower right side.

3) Check that the image remains circular as the illumination is varied through cross-over with the BRIGHTNESS control.

Note: A alternative method of correcting the condenser astigmatism is to examine a under saturated filament image. The COND STIGM controls should be adjusted until a very sharp image of the filament is obtained.

4) Saturate the filament.

Specimen Exchange

1) Insert the specimen holder into the slot on the side entry specimen exchange devise. Avoid turning the holder as this will result in air being admitted to column.

2) Turn the specimen chamber pre-pump switch to EVAC. This will result in the red pumping lamp being illuminated.

3) After about 15 seconds the SPEC EVAC lamp will turn to green.

4) Turn the specimen holder clockwise until it stops and push it into the column. Make sure the holder is not pulled from your hand as this may result in damage to the holder and stage.

5) To remove the holder, pull it out and turn it counterclockwise. Pull the holder once again and turn it counterclockwise.

6) Turn the specimen pre-pump switch to AIR. Pull out the specimen holder.

Adjustment of specimen height (Z-control)

1) In the SA mode set the magnification to 5,000X.

2) Center a distinguishable feature using the stage controls.

3) Focus the image with the FOCUS ? and ? controls.

4) Turn on the power switch for the drive unit and adjust the tilting speed to the 2 o'clock position.

5) Operate the foot switch and tilt the specimen about 10 degrees.

6) If the feature moved upon tilting, adjust the Z-control to bring the image back to the original position.

7) Refocus the image.

8) Return the tilt to angle zero.

9) Repeat steps 5-8 with increasing magnification until minimal image shift is observed.
An alternate method for adjusting the specimen height is to continually tilt the specimen back and forth while adjusting the Z control. Continue adjusting until the specimen movement is minimized.

Selected area diffraction (SA Diff)

1) Depress the SA button.

2) Set the magnification with the MAG buttons.

3) Insert the selected area diffraction aperture (SAD aperture) and select the appropriate sized aperture.

4) Focus the edge of the SAD aperture using the DIFFRACTION SPOT ? and ? buttons.

5) Focus the specimen image using the FOCUS ? and ? buttons.

6) Depress the DIFF button. If a objective aperture is in the column, remove it.

7) Select the desired camera length with the MAG keys.

8) Focus the diffraction pattern with the DIFFRACTION SPOT ? and ? controls.

Carry out either a Voltage Alignment or a Current Centering Alignment

Voltage alignment

1) Move a recognizable feature to the center of the screen and image at 50,000x.

2) Depress the HV MODUL key. the image will move radially.

3) Adjust the BEAM TILT until the rotation of the image is minimized at the center of the screen.

4) If the beam has moved off the screen, move it back with the BRIGHTNESS CENTERING controls.

5) Turn off the HV MODUL key.

 

Current centering

Note: if a proper voltage centering has been performed, it is usually unnecessary to perform a current centering.

1) Center a recognizable feature and image at 50,000X.

2) Turn on the OBJ MODUL key. A rotating motion is observed.

3) Using the BEAM TILT controls, move the center of rotation to the center of the screen.

4) If the beam has moved off the screen, re-center it with the BRIGHTNESS CENTERING controls.

5) Turn off the OBJ MODUL key.

Shut down

1) Slowly turn the FILAMENT knob fully counterclockwise.

2) Depress the READY/OFF button twice.

To shut the HT off:

1) Wait about 5 min. after turning off the accelerating voltage, then turn off the COL switch.