Prepare a gain reference

  1. First set up even illumination on the CCD detector
    1. Ensure that the transmission electron microscope (TEM) is in Imaging mode, with no sample features in the spectrometer field of view
  2. For dedicated spectrometers
    1. Go to the EELS Acquisition floating window
      1. Set the dispersion to 0.0 eV/ch
      2. Start energy to 0 eV
      3. Set the aperture size to the minimum size
    2. Open the EELS Acquisition Setup Options dialog and choose a camera mode with 1x1 binning and Show Original Image checked.
    3. Select View in the EELS Acquisition dialog, with exposure set to 0.1 s; the intensity in the spectrum 2D view should be centered, if not adjust the Start Energy until the beam is centered
    4. With the spectrum view still running, increase the entrance aperture until the whole detector is completely illuminated
      1. Adjust the beam on the TEM to attain a count level of about 1/3 the saturation limit (21,000 for 16-bit detectors), and leave the system viewing for about 2-5 minutes to "anneal" the scintillator
    5. Stop the spectrum view
  3. For imaging filters
    1. Ensure the spectrometer is in unfiltered imaging mode
    2. Start a camera preview with 4x binning and ~ 0.125 s exposure and adjust the beam to ensure even illumination on the detector.
    3. The image intensity should be approximately 20,000 counts at this binning and exposure. If not, try changing the spot size or emitter settings
    4. Stop the camera preview
  4. In the Camera menu, select Prepare Gain Reference to make sure the Target Intensity and Frames to Average are set to
    1. Prepare a gain referenceGIF 2000 and earlier Gatan imaging filter (GIF) users – 8000 and 10 respectively
    2. Enfina, GIF Tridiem®, GIF Quantum® and Enfinium™ users – 21000 and 10 respectively
  5. Follow any on-screen prompts during the automated gain reference acquisition procedure

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