Sample Alignment Quick Reference
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Prior to this section make sure beamline alignment has been performed (Beamline Alignment Quick Reference)
1) Verify optic alignment
Perform CCD changeover to Coolsnap
Drive focusing optic into beam, adjust OSAX and OSAY so outgoing focused beam is not clipped and remnant central parallel beam intensity is minimized
Close NES slits to 0.1x0.1, adjust FOMX and FOMY to center optic on beam axis - outgoing wavefront clipped by slits should look symmetric around the edges
Record this as your "optic in" position, move FOMX so parallel beam is unobstructed with NES slits at 1x1 (should be ~+4000 relative move) - this is your "parallel beam" position
NOTES:
i) Central stop may be offset from the center of optic - do not simply put image of central stop in the center of the beam footprint when aligning optic
2) Mount and visually inspect sample
Move Objective Y to 0.0, rotate Sample Theta to 90 degrees, vent chamber
Remove old sample, slide new sample stick into machined slot, verify sample is flush with bottom of slot
Pump down chamber
View sample from top camera, roughly adjust SAMZ to put surface on marked focal plane
View sample from upstream camera, roughly adjust SAMY to put intended scanning region on marked focal spot
NOTES:
i) Camera positions will not be accurate until chamber is pumped down
3) Flatten sample with x-rays
If phi alignment is necessary, move SAMX so a side edge of the sample is visible in downstream parallel beam image
Observe edge position under SAMY motion of +/-1000, adjust Sample Phi until visible edge is parallel to this motion
Rotate Sample Theta to 0.0 degrees
Move SAMX so the front face of the sample is visible as an edge in the downstream parallel beam image
Adjust Sample Theta to find crossover between leading edge and trailing edge obstructing beam, set this to be user Theta=0.0
Observe surface edge position under SAMY motion of +/-1000, adjust Sample Chi until visible edge is parallel to this motion
NOTES:
i) Stop coarse motors frequently during these steps
ii) Make sure SAMY ends back up at coarse height found above at the end of this section