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basic alignment of tecnai f30

Before Starting. Check the vacuum (gun

Antony
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basic alignment of tecnai f30

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    1. Basic Alignment of Tecnai F30 Yan Cao Sept. 9th 2002 Case Western Reserve University

    2. Before Starting Check the vacuum (gun = 1, column < 20) Remove the objective aperture Refill liquid N2 (turn away the monitor) DO NOT spill N2 on the glass of the viewing chamber

    3. Inserting the Specimen Holder Select the appropriate holder, click “return” Make good connection with ?-tilt cable Hear the tilt motors reset the ?-tilt Push the holder into column carefully Check the vacuum, open V4 and V7

    4. Abnormal Behavior Do not insert the holder into the column Switch off the turbo pump (7 min down) Make sure V41 and V8 are closed Reset the holder and Remove it NEVER shut off the computer

    5. Condenser Aperture (C1 & C2) Aperture sizes influence coherence convergence, spot size and total current Make the beam stay centered on the screen Ensure the reproducible illuminating conditions Misalignment leads to a beam tilt

    6. FEG: TEM-BF Mode C2 aperture : 100/50 ?m Objective : 100 ?m Extractor : 3.5 ? 4 kv Emission : < 100 mA Gun Lens : 1-3 Spot size : 1 Magnification : 500 k ~ 750k

    7. FEG – EDX Nanoprobe Mode C1 aperture : 30 ?m C2 aperture : 150 ?m Objective : No Extractor : < 4.6 kv (i.e. crossover mode) Gun Lens : 5-8 (depending on current) Spot size : 5 Do not change saved FEG registers

    8. Alignment Procedure Eucentric focus Gun alignment / condenser stigmator Beam tilt pivot point Rotation center Coma-free pivot point Coma-free alignment

    9. Eucentric Focus Importance Area of interest stays centered when tilting Defines the reference value for the objective-lens current Procedure Press Eucentric focus button to set the objective lens at eucentric height Press wobbler button, focus specimen by adjusting “z height”, not “focus”

    10. a. Focus without use of the wobbler b. Focus after use of the wobbler

    11. c. Out of focus - wobbler in chosen direction. d. Out of focus - wobbler perpendicular to c.

    12. Alignment Procedure Eucentric focus Gun alignment / condenser stigmator Beam tilt pivot point Rotation center Coma-free pivot point Coma-free alignment

    14. Condenser Stigmator Purpose Correct for beam astigmatism Determine the relation between a change in stigmator setting and the beam shift Misalignment lead to a beam shift Procedure Focus the beam (not completely). The current through the stigmator is wobbled in the x or y direction. Minimize beam movement

    16. Alignment Procedure Eucentric focus Gun alignment / condenser stigmator Beam tilt pivot point Rotation center Coma-free pivot point Coma-free alignment

    17. Beam Tilt Pivot Point Purpose Make sure the beam does not shift when tilted Keep beam centered during rotation-center alignment, focusing with the wobbler and DF Procedure Set up the image. Align x or y pivot points, until a tilting beam remain centered on the specimen, giving no beam shift

    18. Alignment Procedure Eucentric focus Gun alignment / condenser stigmator Beam tilt pivot point Rotation center Coma-free pivot point Coma-free alignment

    19. Rotation Center Purpose Ensure the beam is along the optical axis of the objective lens Minimizing lens aberrations and image movement during focusing Procedure Wobble the objective lens current. Image go through focus Align the rotation center to minimize the movement of the image Based on beam tilt. Beam alignment procedure.

    20. Alignment Procedure Eucentric focus Gun alignment / condenser stigmator Beam tilt pivot point Rotation center Coma-free pivot point Coma-free alignment

    21. Coma-free Pivot Points Purpose Ensure the beam stays well-centered while wobbling Obtaining reliable and accurate coma-free alignment Procedure Center the beam and focus the image. The beam is wobbled in x or y directions. Adjust coma-free pivot point until the two wobbling beams overlap. Minimize the movement

    22. Alignment Procedure Eucentric focus Gun alignment / condenser stigmator Beam tilt pivot point Rotation center Coma-free pivot point Coma-free alignment

    23. Coma-free Alignment Purpose Ensure the beam along optical axis of the objective lens Obtaining reliable and accurate high-resolution data Procedure Center the beam and focus the image The beam is wobbled in the x or y direction with a set amount of beam tilt. Adjust the coma-free center until two “wobble” images have the same defocus.

    24. Do not save settings in “Filter Control” Do not overexpose the CCD Familiar with the button for manually closing V7 (in case of vacuum emergency) Do not save your experimental data to microscope computer, but the black dell Never stop an XEDS or EELS in STEM mode

    25. Thanks for your attention!

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