G3 Upstream X-Ray Flight Path Alignment Procedures
 

Complete this procedure ONLY if:

1. You are familiar with SPEC, x-ray hardware, and hutch protocol.
2. I₂ intensity is anomolously low, e.g. if the beam has moved due to adjustment of upstream optics.
3. You are confident that the "2theta" and "alpha" axes of the diffractometer table are aligned with the current flight path position. If this is not the case, the diffractometer alignment procedure must be completed first.

Notes

a)Flight path ion chambers are labeled I₀, I₁ and I₂.Slits are labeled S₁ and S_2.

b)Coordinate axes and cardinal directions coincide with the diagrams below.
 
 

Procedure

1. Record current positions of motors: zeast, zwest, yeast, ywest, edgeb, edget, edgen, edges, y, zs, zne, znw.
2. Set S₁ to 1mm tall by 20 mm wide, symmetrically.
3. Scan motor zeast over a wide range to detect all components of the x-ray beam.
4. Center zeast on the spot of greatest intensity.
5. Set S₁ to 20 mm tall by 1 mm wide, symmetrically.
6. Scan motor yeast over a wide range to detect all components of the beam.
7. Center yeast on the spot of greatest intensity.
8. Repeat steps 3-5.
9. Open S₁ completely. The east y-z jack is now aligned.
10. Repeat 3-9 for S₂, replacing zeast with zwest and yeast with ywest. The S₂ slit edges motors are: edget, edgeb, edgen, and edges. The SPEC command to set S₂ symmetrically to 1 mm tall by 20 mm wide, is: 

11. The west y-z jack is now aligned. Write down new positions of motors zeast, zwest, yeast, ywest, edgeb, edget, edgen, and edges.
12. Move diffractometer motor y by (ywest_new - ywest_old).
13. Move diffractometer motors zs zne and znw by (zwest_new - zwest_old).
14. The center of diffractometer rotation is now aligned to the beam. Record new positions of y, zs, zne, znw, and take a burn.

	Hutch
			Flight Path