Running Tomography

The XPD acquisition and analysis stack supports the acquisition and processing of tomographic data in both full field and pencil beam geometries.

Running a tomographic scan

There are three scans currently supported. Each scan is delineated by different metadata added at the beginning of the scan:

  1. Full Field

{'tomo': {'type': 'full_field',
          'rotation': 'motor1',
          'center': 123.3}}

  1. 2D Pencil Beam

{'tomo': {'type': 'pencil',
          'rotation': 'motor1',
          "translation": "motor2",
          'center': 123.3}}

  1. 3D Pencil Beam

{'tomo': {'type': 'pencil',
          'rotation': 'motor1',
          "translation": "motor2",
          "stack": "motor3"
          'center': 123.3}}

You will need to fill in the center field with the correct rotation axis location (found via a line scan of the sample). You will also need to fill in the various motor names associated with the sample rotation, translation, and stack translation (z direction).

Here is an example call to xrun running a tomographic scan

xrun(3, bp.grid_scan([pe1c],
     z_motor, 0, 2, 10,  # This is the out of plane translation
     theta_motor, 0, 180, 181, True,  # The theta rotation
     x_motor, 200, 401, 200, True,  # The translation
        md={
            "tomo": {
                "type": "pencil",
                "rotation": "theta_motor",
                "translation": "x_motor",
                "stack": "z_motor",
                # we subtract 200 because we are starting at 200
                # (and the center is measured in pixels)
                "center": 300 - 200,
            }
        },
    )
)

Once this scan starts the automated data processing software will kick in to create reconstructions of the data for each quantity of interest.