Step 1: Sample Preparation
• Ensure the sample is electron transparent (~100 nm thick) to allow proper diffraction.
• Mount the sample onto a TEM grid and place it in the specimen holder.

Step 2: Insert the Sample into the TEM
• Load the holder into the TEM and ensure the vacuum is stabilized.
• Adjust the sample height to be at the eucentric position (optimum focus position).

Step 3: Align the Electron Beam
• Set the microscope to parallel illumination mode using the condenser lens.
• Adjust the beam spread to ensure even illumination on the sample.

Step 4: Locate the Region of Interest
• Use bright-field (BF) or dark-field (DF) imaging to find a defect-free region or an area of interest.
• Focus the image properly to ensure the region is well-defined.

Step 5: Select the Zone Axis
• Tilt the sample using the goniometer stage to align it along a major zone axis (e.g., [100], [110], [111]).
• Check for symmetrical diffraction spots in the Ronchigram or diffraction pattern preview.

Step 6: Insert the Selected Area Aperture (SAA)
• Switch the microscope to diffraction mode.
• Insert the selected area aperture into the image plane to limit the region contributing to diffraction.
• Choose an appropriate aperture size (smaller for localized analysis, larger for averaging over a region).

Step 7: Adjust the Diffraction Pattern
• Ensure that the transmitted beam (central spot) is at the center of the pattern.
• Adjust the camera length to control the spacing of diffraction spots.
• Focus the diffraction pattern by adjusting the diffraction focus knob.

Step 8: Capture and Analyze the SADP
• Record the SADP using a CCD camera or direct electron detector.
• Index the diffraction spots by measuring interplanar spacings and identifying the zone axis.