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RHEED (Reflection High-Energy Electron Diffraction) analysis automatically extracts and quantifies diffraction features from RHEED videos and images. It supports stationary stages, rotating stages, and real-time streaming via screen capture. For rotating recordings, the pipeline automatically detects the rotational period, identifies high-symmetry reference frames, and applies per-rotation corrections so that metrics are extracted consistently at each azimuthal angle.

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Overview

The RHEED pipeline processes data in three stages:
  1. Data cleaning and standardization: auto-classifies the recording type (stationary vs. rotating), crops to the illuminated region, corrects detector orientation, and for rotating recordings, detects the rotational period and aligns each rotation cycle to consistent azimuthal positions
  2. Pattern extraction: segments diffraction features using deep learning models and quantifies morphological metrics per feature
  3. Timeseries analysis: tracks how extracted metrics evolve across video frames, detects transitions, and identifies changes in surface structure

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Key Metrics

MetricWhat It Tells You
Lattice spacingReal-space lattice constant derived from reciprocal-space feature spacing. Tracks surface reconstruction changes.
StrainRelative change in diffraction feature spacing over time, calculated from horizontal spacing between neighboring patterns.
Oscillation periodPeriod of specular intensity oscillations, related to deposition rate.
Spot countNumber of diffraction features per frame. Changes indicate phase transitions, reconstructions, or target thickness reached.
FWHMFull width at half maximum of specular and first-order spots.
IntensityIntegrated intensity of specular, half-order, and first-order reflections.
For rotating RHEED data, the pipeline automatically detects the rotational period, identifies high-symmetry reference frames, and aligns each rotation cycle before extracting metrics per azimuthal angle. This corrects for variations in rotation speed and ensures equivalent positions are compared consistently across cycles.

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Adding RHEED Data

You can add RHEED data in two ways: uploading video files, or streaming live from your RHEED camera display.

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Upload

Upload RHEED video files directly through the data management page. Analysis begins automatically once the upload completes.

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Stream

Streaming captures your RHEED feed in real time via screen share, with analysis results delivered within seconds.
1

Start a new stream

Click Add Data, then select Stream.
2

Choose your source

Click Choose Source and select the window that displays your RHEED camera feed, the same way you would screen-share on a video call.
3

Adjust the capture region

Drag the blue bounding box to frame the RHEED pattern area you want to capture.
4

Set metadata (optional)

Enter a name for the stream and any other metadata. If your stage is rotating, enter an approximate rotation rate as a starting point for automatic period detection. Leave the stage rotation field blank for stationary stages.
5

Start the stream

Click Start Stream. Analysis begins immediately and results appear in the workspace as frames are processed.
During an active stream, you can pause, resume, or end the stream from the workspace. Only the user who started the stream can control it.

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Viewing Results

Once processing completes (or during a live stream), the RHEED workspace shows several sections:Video player: Scrub through the recorded or live video. Reference frame positions are highlighted on the scrub bar for rotating recordings. You can jump to a specific frame number or drag the scrubber to isolate a moment in time.Growth analysis chart: The main analysis view. Select which timeseries to plot (lattice spacing, strain, intensity, FWHM, spot count, oscillation period) and choose the azimuth angle for rotating data. Transition zones appear as shaded regions when the pipeline detects significant changes in the underlying signal.Saved patterns: Extract individual frames for detailed fingerprint analysis. Click Save Frame to extract the current video frame. Each saved frame shows the fingerprint overlay with extracted diffraction features, intensity maxima positions, and horizontal spacing between the specular spot and nearest features.

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Azimuth Calibration

For rotating RHEED recordings, the pipeline automatically detects the rotational period and identifies high-symmetry reference frames. You can refine these in the azimuth calibration panel:
  • Label azimuths with crystal orientation names (e.g., Al[100])
  • Set calibration to convert from pixels to inverse Angstroms, enabling real-space lattice spacing values

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Reanalysis

If you need to adjust analysis parameters, open the workflow configuration drawer to update reference frames or rotational period, then re-run the pipeline.

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Comparing Patterns

Save multiple frames and use the pattern comparison tools to view fingerprint overlays side by side or generate difference masks between two patterns. This is useful for identifying subtle changes in surface structure across a growth run.

Detect Anomalies During a Run

Use RHEED metrics as part of real-time growth monitoring.

Identify Uniformity Issues

Analyze RHEED data consistency across a growth.