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FEI Titan ETEM

Basic TEM Mode SOP

Reset Checklist

Log In
  • Log into Badger (use either your own computer, mobile Badger, or the support PC) to enable the Titan computer.
  • Check that all the necessary software is open.
    • After log in, ensure the microscope user interface, TIA, Digital Micrograph, and the Image Corrector software are all running.
    • On the Gatan PC, check that Digital Micrograph is running. If it was open before the microscope user interface, close and reopen Digital Micrograph.
Review TEM Status
  • In the microscope UI look at the Setup tab.
  • Status of the Microscope should show “Col. Valves”.
  • HT and Operate tabs should be in yellow. HT is set either at 300kV or 80kV.

  • Titan can be run in one of three modes:

    1. ETEM
    2. High Vacuum - Turbos On
    3. High Vacuum - Turbos Off

From the ETEM vacuum page choose the desired mode. For most regular cases, the microscope is run in ETEM mode.

  • All the vacuum values in log units should be in green. Vacuum Log should as follows:
Gauge Log Value
Gun 1
Liner <10
Octagon 1
Projection <30
Buffer tank <50
Backing line <80

In ETEM mode the Octagon will always at 1 log. User should check PP/PO gauge after loading the sample (more description given in the load sample section below)

  • Fill in the liquid nitrogen dewar.
  • Verify that apertures are as follows:
Mechanism Value
C1 2000
C2 150
C3 2000
Objective None
SAED None
  • To run properly, at any given time, Titan has five softwares open across two computers. On PC 1 ( which runs the TEM), following softwares are open: TEM user interface, image corrector, Digital Micrograph, TIA. In PC 2( which runs the OneView Camera and GIF) Digital Micrograph( version 3.X) must be open.
  • In addition, ‘ETEM vacuum page’ and ‘beam blanker shutter’ software should be open as well to facilitate better operation.
Sample Loading
  • Reset the holder from the stage tab if not already set to zero.
  • The front pin of the sample holder should be aligned to the ‘close’ position of the goniometer. Push the sample holder until a resistance is felt, then go past it gently until a full stop is reached. This should start the turbo pump.
  • Select the ‘holder type’ in the microscope UI. After the turbo reaches full speed an airlock cycle should run for 2 minutes. Wait until it’s is complete. A red Led light on the goniometer will go off at this point.
  • A user should complete the following next steps within 90 seconds.
  • Rotate the holder counter-clockwise until a full stop is reached. Gently glide the holder inside the column .
  • Turn off the Turbo pump and wait for PP/PO gauge value to go<10-6 mbar. Remember that in the ETM mode Octagon is always at 1 log. So, checking PP/PO gauge is the only way to check the column vacuum.
Loading a FEG Register

Loading a FEG register can be a good way to start the session with a common alignment. This will also be the best way to change the system between TEM and STEM.

  • Find the panel labeled “FEG Registers” in the microscope UI and sort the available registers by data; you may need to click the data header twice to bring the most recently updated registers to the top.
  • Find the TEM_USER or STEM_USER FEG register you need for your experiment and click it to highlight.
  • Click “Set” to load the FEG register to the microscope server.
Euecentric Height

Eucentric height alignment must be completed after loading each sample and before imaging on camera.

Do not skip this step

Press the “Eucentric Focus” button to both set the defocus to 0 nm and normalize the lenses.

  • Make sure you are on a non-vacuum region of the sample - something that will scatter well even with lateral stage movement.
  • Condense the beam to a point to see the diffraction pattern caused by the stage being off of proper eucentric height.
  • Use the Z-axis buttons to move the stage in a direction collapsing the diffraction pattern into a point. These buttons are pressure sensitive - the harder you press, the faster the stage will move.

Alpha Wobbler

The alpha wobbler can also be used to reach true mechanical eucentric height by minimizing stage motion. Minimized image contrast can be used to maintain the eucentric position during normal operation.

Tuning Before Direct Alignments

Before proceeding to ‘Direct Alignments’ a user must check that the monochromator is not partially blocking the beam, C2 aperture is centered, and condenser stigmation is absent.

  • Monochromator Shift and Focus:
    • Patial blocking of the beam by the monochromator is visible as a jagged edge on one side of the beam. It is visible in the low mag SA modes. To fix, go to Monochromator🡪 Monochromator Tune. Click on ‘Shift’. Use multifunction to move the jagged edge away from the beam path.
    • Monochromator focus can be used to get a desired value of screen current/dose. To get there click on ‘Focus’ tab. Use intensity knob to get to a desired value of the screen current. Hint: As monofocus value approaches zero the screen current increases.
  • C2 Aperture Centering: Go through the cross over point of the over and underfocus states of the C2 lens using the intensity knob. In practice, the beam will go from a diverged to converged and then to a diverged (on the other side) condition. A user must track this movement of the beam and make sure it is concentric at the converged point. If not, click on the C2 aperture ‘Adjust Tab’. Use multifunction knobs to make the beam movement concentric. A user needs to run multifunction and intensity knobs iteratively until the desired level concentric movement happens.
  • Condenser Astigmation: Make the beam to the size of the large circle on the fluscreen. If the beam is not round, Go to the Stigmator tab ( from the below right corner of the UI)🡪 Condenser. Use multifunction knobs to make the beam round. Repeat the same with a beam size matching the smaller circle.
Direct Alignments

The basic alignments are found under the Align tab🡪 Direct Alignments. Be at a mag between 200-300kX for these alignments.

  • Beam Tilt Pivot Point X: Make the beam size match to the large circle on the fluscreen. Click on beam tilt pivot point X in the direct alignment tab. Reduce the edge of the beam movement using multifunction X and Y. Click ‘Done’ once finished.
  • Beam Tilt Pivot Point Y: Same as above.
  • Beam Shift: Click on beam shift. Use multifunction knobs ( which becomes alignment beam shift) to center the beam at the fluscreen. If the beam is lost after clicking on the beam shift tab, go to a lower mag until the beam is visible and center it using multifunction knobs. Increase the mag to above 200kX and center the beam again. Do not use the track ball to center the beam at this alignment step. Click ‘Done’ once finished.
  • Rotation Center: Spread the beam to match the size of the CCD camera ( four comma signs on the fluscreen). Choose a suitable feature of the sample and bring it to the center. Press R1 to lift the fluscreen. Start view on the OneView camera. Make sure the image is close to focus. Click on the Rotation center button under direct alignment. Reduce the lateral x and y movements of the sample using multifunction knobs. Ideally, the sample movement should only be confined to the z-direction. Click ‘Done’ once finished.
Corrector Tuning Procedure
  • Find a suitable flat amorphous area. Be at underfocus so that 5-6 thon rings are visible in the FFT.
  • For 300kV be around 200kX-300kX mag and for 80kV be around 100kx-200kX.
  • From the Stigmator tab make sure that ‘Objective’, ‘Diffraction’, and ‘Image A1’ are set to zero.
  • In the OneView Digital Micrograph go to Camera🡪 Configure Camera. Uncheck ‘Flip around vertical axis’.
  • In the Image Corrector Software go to measurement tab 🡪 C1A1 tab. Start C1A1 measurement. In this measurement, a user does not change C1. The aim is to reach to an A1 value of 5nm. To get there use ‘A1Course’.
  • Go to Fast Tableau. Set the outer tilt angle of 15 mrad. Start Tableau measurement. The measurement from fast Tableau should yield a1<5nm and A2,B2<5nm. If the values are not to the expectation, click ‘accept’ and this will take you to correction tab. Change whichever aberration coefficients are bad. If all of them ( A1,A2, and B2) are bad click on 1st+2nd. Choose the percent strength appropriately depending on how far you are off from the desired value. Usually, 75% is a good starting point.
  • Go to Standard Tableau. Set the outer tilt angle of 25 mrad. Start Tableau measurement. The measurement from fast Tableau should yield C3,A3,S3 <5μm. If the values are not to the expectation, click ‘accept’ and this will take you to correction tab. Change whichever aberration coefficients are bad. If both A3 and S3 are bad click on A3+S3. Choose the percent strength appropriately depending on how far you are off from the desired value. Usually, 75% is a good starting point. If C3 is bad, click on C3 and use the up/down arrow to go to the desired value. You can choose the C3 step size in from 0.1 to 20 μm depending on how much off C3 value is. Typically, 0.5-5 μm step size is good while changing C3.
What are acceptable corrector values?

Typical values of aberration coefficients one should aim to get <1Å resolution:

Resolution < 0.10 nm (20 mrad) Resolution < 0.08 nm (24 mrad)
A1 < 5 nm < 5 nm
A2 < 100 < 50
B2 < 100 < 50
C3 ~ -8 μm ~ -8 μm
A3 < 5 μm < 1.5 μm
S3 < 5 μm < 1 μm
Saving Data
  1. OneView Camera is the main camera in Titan and it’s run by Digital Micrograph (Version 3.X).
  2. In the home tab on the right- hand side of the GMS there is an icon for TEM imaging. Usually this tab is open, and the user should find different OneView imaging options which includes choosing proper pixel sizes(512 to 4K ), exposure for viewing and capturing images.
  3. To autosave the data, the user needs to click on the settings wheel icon in this tab. It’ll open the ‘auto save setup’ .
  4. Click on the ‘auto save setup’. A new window will open where the user will be able to choose the right folder path to save the data and create a suitable file name.
  5. The files are saved in the native OneView RAID drive. where users can create folders with their names. The saved files can be transferred to the Titan supportPC by copying them from the RAID drive.
  6. The filename can be created by selecting different microscope conditions such as, magnification, detector type, etc. or by creating user-defined string.
Removing Holder
  • Verify the column valves are closed and that no objective aperture is selected.
  • In the microscope user interface Search tab Stage2 control flap-out, under Holder press the Reset button.
  • Unloading the holder is essentially the opposite of loading, with an extra step:
    • Removing the holder pulls against atmospheric pressure, shifting the column sideways. Place one hand on the goniometer with your thumb on the purple cover and prepare to apply an equal amount of force against the holder pull.
    • Pull straight out until stop, rotate clockwise until stop, then pull the rest of the way out of the airlock. The final pull should be a continuous motion - do not stop partway.

    Never apply excessive force on the mechanisms

    Both the goniometer mechanisms and the small front pin can be damaged if you force the holder.

Cryocycle

The last user scheduled for the day must run the cryocycle. This procedure should be followed before logging off.

  • If you are the last user of the day and in ETEM mode, there is no option or need to run ‘cryo-cycle’ as the bank of turbo pumps will automatically handle all cold trap outgassing.
  • If you are in ‘Hv-Turbos On’ or ‘HV Turbos Off’ mode:
    1. Go to the Setup tab and open the Vacuum flap-out.
    2. Click the “Cryocycle” button.

In both cases:

  • Carefully remove the liquid nitrogen dewar from the stand and use a funnel to pour the LN2 back into the transfer dewar.
  • Put the small dewar cup or styrofoam pitcher below the cold trap copper braid to catch melt off.
  • Place the dewar upside down and at an angle in the styrofoam box.
Log Off
  • Replace cover on fish bowl.
  • The microscope should be brought back to 2condenser imaging mode (μProbe mode) from whichever mode the user were working at.
  • The condenser2 aperture should be set to 150 μm.
  • The microscope should be set to lower SA magnification(<10,000X).
  • Make sure the beam is broad enough (typically matches the size of the bigger circle in the fluscreen.
  • Close the column valves.
  • Check liquid nitrogen:
    • If you are NOT the last user of the day, fill the LN2 dewar in the cold trap
    • If you ARE the last user of day, follow the cryocyle instructions.
  • Log in to Badger and click Disable under the Titan.

Extra Steps

Common Issues

Sometimes the beam is lost after switching the voltage or by some other actions by the previous user. If it happens follow the steps below :

  1. Be at lower SA mag (<10000X).
  2. Move the sample stage with the joystick or by double-clicking on the circle in the stage tab. If the sample is blocking the beam this step will solve it.
  3. Turn the intensity knob in any direction until a beep sound comes up. Go a couple of turns in the opposite direction. If beam is too diverged or converged this step will help making the beam of suitable size.
  4. Click on the beam shift from the direct alignment under the alignment tab. IF beam shift is misaligned, this step will help fix it.
  5. In crease the monofocus to =/- 100. Use ‘find beam’ under monochromator tune. If monochromator is off-centered, this step will help.
  1. The Titan can be run at 300kV or 80kV. Stabilizing the beam/image after switching voltages takes approximately 4-6 hours. A user should plan accordingly in consultation with the TEM staff.
  2. To switch voltages, first choose the desired voltage300kV or 80kV) under the ‘High Tension’ tab found under the setup tab.
  3. From the alignment tab click on the flap out arrowa page with alignment files opens up choose the most recent 300kV or 80kV alignment file.
  4. From the monochromator tab find the most recent 2 condenser (μP Probe mode) FEG register with the suitable voltage.
  5. Make sure to see a beam at lower SA magnification.

Common Workflows

One of the most powerful traditional workflows available on a TEM combines high resolution (i.e. lattice) TEM imaging (HRTEM) and selected area diffraction (SAED) to gain deep structural insights into the nature of materials.

K3 Camera

ETEM Operation