Tecnai F20 (basic operations)

• TEM data computer controls Fast Scan CCD holds data and provides access to internet
• FEI control computer controls EM and Slow Scan 4k CCD camera and runs tomography software

Press Scroll Lock 2x to switch screens

Contents

Initial Setup

• Start TCL
  • Click start in dialog box
  • EMMENU (pull down)
  • Select Start EMMenu

• Open vacuum overview (bottom right)
  • IGPI should not read over 15 (6 best value)
  • P3 indicates moisture of film (60 new film-20 dry film)
• Extraction voltage should read ~3900-3950
• Accelerating voltage should be 200kV
• Click Prepump airlock (setup menu)
  • While airlock is prepumping load sample in holder
• CCD Blank enable should be on screen with box checked
  • Instructions to Retrieve CCDBlankEnable Box

Check for beam and alignment before loading sample (NYSBC Staff)

• Insert specimen holder to first stop
• In setup menu open column valves when option becomes available
• Start Low Dose mode before aligning the beam or alignments will be off.
  • If no beam go to Focus and lower magnification, do not adjust the beam in Search
• Condenser Aperture Alignment and Stigmation
• Check condenser aperture size (plastic sections-#4)
• Check alignment of condenser aperture
  • At cross over center beam with beam shift (left control pad)
  • Spread beam and center with aperture X, Y
  • Repeat until beam spreads evenly
• Check Condenser Aperture Astigmatism
  • Bring beam to crossover; if beam is not round
  • Press Stigmator button on left control panel
  • Stigmator menu should pop up
  • Make sure Condenser button is selected
  • Use multifunction knob to make beam round
  • Unclick Stigmator button

Sample Insertion

• Have NYSBC staff insert your sample

Specimen Imaging

• Check vacuum IGP1 should be max 15
• Open column valves

Objective Aperture Alignment and Stigmation

• Check Objective aperture size (plastic sections-#3)
• Put in objective aperture
  • Press diffraction (right control pad)
  • Condense diffraction spot
• Center objective aperture around the spot with the aperture controls X, Y
• Press Stigmator button on left control panel
  • Stigmator menu should pop up
  • Make sure Objective button is selected
• Using CCD camera and Power spectrum bring image to focus
  • If Thon rings are out of round fix with multifunction knobs
• Unclick Stigmator button

Adjust Eucentric Focus

• Press Eucentric Focus on Right control panel
• Move Z +/- to obtain focus
  • if you are having trouble seeing thon rings dropping the magnification may be helpful

• Alpha Wobbler method
  • in Search mode
  • press alpha wobbler Left control panel
  • Move Z +/- to obtain focus

Taking a FilmImage

Taking a CcdImage

Shut down

• Close column valves
• Reset holder
• Remove objective aperture
• Remove sample
• Record date and ending plate number in em-signup database on TEM data computer

End of day shutdown

• Remove Dewar for cold trap and place the cup under the coils
• Run cryo cycle (setup menu)
• Warm up cryoholder if used
• Log out of computers and turn off monitors

Common Problems

Instructions to Locate Beam

Instructions to Find CCD Blank Enable

Acessing status of the FEG

• Open Tecnai User Interface
• Go to Setup/FEG Control panel
  • If the operate button is not yellow FEG is off
  • Call NYSBC or FEI staff

Keeping the beam centered when raising screen (as opposed to offsetting for the camera):

• Workspace Layout
  • Detector Config
  • Uncheck “Auto Mode”

Visit the Cryo EM Web site at http://www.nysbc.org/facilities/CEM

-- DavidStokes - 18 Mar 2005

• Set ALLOWTOPICCHANGE = CemfacGroup , MinghuiHu