EFTEM SI Workflow

The preparation steps for EFTEM spectrum imaging (SI) are largely identical to those used for EFTEM mapping. Proper setup is critical to ensure stable imaging conditions and reliable spectral data.

Prerequisites

• Begin with a well‑prepared sample.
• Ensure the TEM is fully aligned. Accurate ion source tilt, condenser alignment, and optical axis alignment are essential.
• For mapping applications, use a high beam current to improve signal quality.

Microscope and imaging setup

1. Set the objective lens current to its optimal value.
2. Adjust the sample height to achieve coarse focus.
3. Insert and center an appropriate objective aperture to reduce chromatic blurring.
4. Operate the TEM in EFTEM mode or Gatan Imaging Filter (GIF) lens mode to ensure a stable projector lens crossover.
5. Align the zero‑loss peak (ZLP) and focus the spectrometer.
6. Focus the image and carefully correct astigmatism while observing the image on the GIF camera.

Energy filtering and illumination

1. Offset the energy to achieve incoherent imaging conditions (typically a 400 eV energy offset with a 50 eV slit).
2. Optimize the illumination intensity for stable imaging.
3. Carefully refocus the incoherent image at the selected energy loss.

Once these steps are complete, the system is ready for you to configure EFTEM spectrum imaging acquisition preferences.

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