Thickness Map

You can relatively easily produce a relative thickness map using the EFTEM technique by acquiring an unfiltered and zero-loss image from the same region under identical conditions. Once acquired, you can compute the relative thickness map when you utilize the Poisson statistics of inelastic scattering:

\(t/\lambda = -ln (\frac{I_{o}}{I_{t}})\)

where

• \(I_{t}\) = Total intensity (unfiltered)

• \(I_o\) = Zero-loss intensity (elastic or ZLP filtered)

1. To acquire a thickness map, specify the slit width for the zero-loss acquisition and the camera parameters to be used.

   1. The same camera parameters will be applied for both the zero-loss and unfiltered image acquisition.

2. Access the Configure Thickness Map dialog will vary based on the mode you choose.

   1. SingleMap mode – Press the Select Thickness Map button

   2. MultiMap mode – Specify via the MultiMap Configuration dialog

      1. Window Settings – Set the energy loss (0 eV) and slit width for the filter

      2. Detector – Specify the detector settings you want to use

3. Click Capture.

The routine will

• Acquire an unfiltered image followed by a zero-loss (elastic) image

• Correct  any spatial drift between the images

• Compute and display the thickness map