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					Jeol 3000F in TEM mode                                S Lozano-Perez, May 11

Alignment instructions

Things to check before starting the session:

- Have you logged in the Cothi system?
- Is the stage reset to 0? (x, y, z, tilt x)
- Are all apertures out?
- Is the GIF button OFF? If the MAG can be increased above 100kx, it means the GIF
button is OFF. If it is not possible, the button is activated through the software, you can
find it in the Custom menu of Digital Micrograph.
- Is the GIF in Imaging mode?
- Is the “Spectrum Offset” in the GIF window set to 0?
- Is the DV set to -15 and the MAG in the 8-100kx range?

Basic column alignment

At around 20-30kx MAG

1. Gun tilt: In a hole, converge the beam and wobble it by pressing the “Anode wobble”
button. Make the wobbling concentric using the GUN tilt knobs (LH drawer, Gun button
pressed, DEF knobs)

2. Gun shift: Centre the beam (when it’s focussed) at spot size 1 using the GUN Shift
(LH drawer, Gun button pressed, Shift knobs) and at spot size 5 using the Beam shift
knobs.

3. Centre condenser aperture.

4. Condenser stigmatism: Go to a high mag (e.g. 300kx) and converge the beam. Use
Cond Stig knobs to make the beam as small as possible.

For the next 3 steps, I recommend you use parallel illumination. You can obtain it by
going to DIFF mode and focus the pattern using the Brightness knob and focus the
objective aperture by using the DIFF Focus knob. When the two of them are in focus, you
are close to parallel illumination. After this point, you shouldn’t change the Brightness
knob settings until you finish the next 3 steps.

5. Shift purity. In DIFF mode, press the Cond Def Shift button and start the wobbling in
either X or Y. Try to collapse the double spots into one by using the left hand knobs in
the drawer for the X wobbling and the right hand knobs for the Y wobble.

6. Tilt purity. In MAG mode, press the Cond Def Tilt button and start the wobbling in
either X or Y. Adjust the MAG and the beam position (Beam shift) until the beam has a
good size. Try to collapse the double circles into one by using the left hand knobs in the
drawer for the X wobbling and the right hand knobs for the Y wobble. Remember that the
top knob always moves the beam in the direction of the wobble and the bottom knob in
the direction perpendicular. It is not likely that the bottom knob has to be adjusted.

7. HT Wobble. In MAG mode, and still without touching the Brightness knob, find a
feature on the sample (precipitate, edge, dislocation, etc) and centre it on the screen.
Increase the MAG as much as possible while still seeing the feature clearly. Press the HT
Wobble button and try to eliminate the movement of the feature by using the Bright Tilt
knobs (Press Bright Tilt on the right hand console and use the DEF knobs).

8. Objective stigmatism. Using the Obj Stig knobs, either in the drawer or in the console,
try to eliminate the objective stigmatism. It is recommended to go to 250-300kx and
acquire a live image of an edge with amorphous carbon, etc in the MSC camera. Obtain a
Live FFT from the image and use the diffractogram to correct the stigmatism.


Using Nanobeams

- The greater the alpha setting, the greater the convergence angle of the beam (and the
beam current). The smaller the alpha, the more parallel the beam is.

- For EDX point analysis use EDS mode and high alpha settings (higher convergence)

- For EELS or nano-diffraction use NBD mode and small alpha settings (more parallel
beams)

- Beam size and current intensity are controlled by the spot size and condenser aperture
selected

- Alignment consists of three steps. The goal is to obtain a converged beam as small and
uniform as possible.

       1. Condenser stigmatism. With the beam focussed on one spot, try to make as
small as possible with the Cond Stig knobs
       2. Bright tilt. Press HT Wobble button and use Bright tilt knobs to make the
wobble concentric
       3. Centre Condenser aperture. If the condenser aperture is not correctly centred,
the beam will have a halo or “tail”.
       4. This process usually requires 2 or 3 iterations


Things to check after finishing

- Is the spectrum offset 0 in the GIF window?
- Is the GIF in imaging mode?
- Are the MSC and the Fischione HAADF detector retracted?
- Is the Nitrogen tab off?
- Is the EDX shutter closed?
- Have you logged off the Cothi system?
- Is the microscope at standard conditions: Illumination spread, no apertures in, MAG set
to 500kx, stage set to 0?
- Is the blank rod in?
If you are the last user of the day, insert the ACD heater in the LN2 dewar and press the
ACD Heat button in the LH drawer

				
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posted:11/4/2011
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