8. Cycle the Search and Exposure modes in sequence for a few
times until the beam is stable and not moving anymore.
9. Go to the Search mode and remove the beam stop if it is in the
beam path. Search for the crystal target and wobble the stage to
find the eucentric z-height.
10. Find an adjacent area without a crystal and then go to the
Exposure mode. Normalize the lenses using the Eucentric
Focus button. Focus the beam and move it to the screen center.
11. Cycle between the Search and Exposure a few times until the
beam is stable.
12. In the Search mode, locate the crystal target. Tilt the stage to
the target tilting angle.
13. Insert the SAD aperture to select the crystal area. Insert the
beam stop. Make sure that the origin of the diffracted beam is
under the beam stop.
14. Turn on the beam blanker before switching to the
Exposure mode.
15. Switch to the Exposure mode. Raise the screen and record the
diffraction pattern on the digital camera for 30 s.
16. Tilt the stage back to 0
and repeat the steps for recording the
diffraction pattern of another crystal. If moving to another grid
square, repeat from step 10.
3.2.4 Electron Imaging
1. Insert the C2 aperture. Turn on the Low Dose system and align
the three modes, which are Search, Focus, and Exposure mode.
The spot sizes used for three modes are recommended to be
the same.
2. In the Exposure mode, set the spot size and beam intensity for
imaging. If one uses the counting or super-resolution mode in
direct electron detector (DED) camera, the intensity will need
to be adjusted to a counting rate that minimizes the
coincidence loss.
3. Insert the objective aperture with a larger size, for example,
70 μm in diameter. Align the position of the objective aperture
in the diffraction mode.
4. Set the magnification to have a resulting pixel size for obtaining
an appropriate target resolution.
5. Align the images and stage position of the target area by
adjusting the image shifts in Search mode and stage shifts in
Exposure mode.
6. In Focus mode, set the Focus distance and Focus angle along
the tilt axis to be away from the target imaging area in about
1.5 μm. Set a higher magnification than that of the Exposure
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Ka-Yi Chan et al.
times until the beam is stable and not moving anymore.
9. Go to the Search mode and remove the beam stop if it is in the
beam path. Search for the crystal target and wobble the stage to
find the eucentric z-height.
10. Find an adjacent area without a crystal and then go to the
Exposure mode. Normalize the lenses using the Eucentric
Focus button. Focus the beam and move it to the screen center.
11. Cycle between the Search and Exposure a few times until the
beam is stable.
12. In the Search mode, locate the crystal target. Tilt the stage to
the target tilting angle.
13. Insert the SAD aperture to select the crystal area. Insert the
beam stop. Make sure that the origin of the diffracted beam is
under the beam stop.
14. Turn on the beam blanker before switching to the
Exposure mode.
15. Switch to the Exposure mode. Raise the screen and record the
diffraction pattern on the digital camera for 30 s.
16. Tilt the stage back to 0
and repeat the steps for recording the
diffraction pattern of another crystal. If moving to another grid
square, repeat from step 10.
3.2.4 Electron Imaging
1. Insert the C2 aperture. Turn on the Low Dose system and align
the three modes, which are Search, Focus, and Exposure mode.
The spot sizes used for three modes are recommended to be
the same.
2. In the Exposure mode, set the spot size and beam intensity for
imaging. If one uses the counting or super-resolution mode in
direct electron detector (DED) camera, the intensity will need
to be adjusted to a counting rate that minimizes the
coincidence loss.
3. Insert the objective aperture with a larger size, for example,
70 μm in diameter. Align the position of the objective aperture
in the diffraction mode.
4. Set the magnification to have a resulting pixel size for obtaining
an appropriate target resolution.
5. Align the images and stage position of the target area by
adjusting the image shifts in Search mode and stage shifts in
Exposure mode.
6. In Focus mode, set the Focus distance and Focus angle along
the tilt axis to be away from the target imaging area in about
1.5 μm. Set a higher magnification than that of the Exposure
260
Ka-Yi Chan et al.