Setup df preset¶

Microscope setup for df preset¶

1. Center the smallest C2 aperture you have.
2. Center the beam and set in nanoprobe parallel illumication and eucentric focus in SA range imaging mode.
3. Change spot size to larger number such as spot 10 and center this beam is needed through Direct Alignment reset Beam Shift.
4. Change gun lens to get much weaker beam. For example from 3.3 to 7.1 reduces the beam current to 25%. You probably won't be able to see the beam any more on the flucam.
5. Push the diffraction button on the control panel to put this in diffraction mode.
6. Select desired camera length
7. Push the eucentric button on the control panel to focus the beam on the diffraction plane.
8. Insert beam stop and center the diffraction beam behind it.

Camera setup for df preset¶

dimension: 2048 x 2048
binning: 2 x 2
exposure time: 1000 ms (not used during movie collection, but used for DPreview node)

Cycle through hl and df presets a few times to allow it to settle on lens normalization before adjusting df preset diffraction shift again. Repeat until satisfied.¶