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Update Calibrations

skoupy_r
2024-03-15 17:22:53 +01:00
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Calibrations.md

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Step size - magnification calibration
##### Scanning step correction
Scanning step size is given by magnification and number of scanning points giving together field of view. In reality, original calibration may not be perfectly accurate and own re-calibration may be needed. Scanning step calibration is based on known inter-atomic distance. In our case \ce{SmB6} in [110] orientation where \ce{Sm} to \ce{Sm} distance is 2.92 or 4.13 \AA respectively. Line of 23 \ce{Sm} atoms was imaged in 499 pixels, 1 pixel is $22 \cdot 2.92 / 499 = 0.1287$ \AA. Microscope field of view at 30e6 magnification is 7.154 nm here divided into 512 pixels (pixel 0.1397 \AA). Correction factor between real and nominal pixel size is then $0.1287/0.1397 = 0.9212 = 92.12\% $
![calib-step](uploads/311e011f544aa091991f8a591ce8f02e/calib-step.PNG)
Pixel size calibration on \ce{SmB6} sample. Known \ce{Sm} to \ce{Sm} distance (2.92 \AA) is recalculated into real pixel size. Line profile is computed as sum of 7 rows to suppress image noise.