NOTE: We align everything to DG1 slits.

  1. Make sure lenses are OUT (if not intentionally left IN for continuous shifts)
  2. Look at the FEL on DG1_YAG (cxi_dg1_yag_gige camera), use Slits 1 (DG1 Jaws) as reference. Transmission ~0.1 to 0.2.
    1. If the beam is not centered on the Slits 1 (DG1 Jaws) (or complete off)
      1. Call ACR for vertical pointing
      2. Use HOMS mirror pitch (mr2l0_homs_pitch) for horizontal pointing: LFE home button → Mirrors → mr2l0_homs_pitch
        • The motor position depends on the photon energy we use
        • ~2.2 urad for 10 keV
        • ~5.44 urad for 16 keV
  3. Bring up and look at the FEL on DG2_YAG  (cxi_dg2_yag_gige camera), transmission ~1E-4, move DG1 YAG out
    1. Close DG1 slits until we see hard edges from the lists, these will be our references for centering the other slits
    2. Set markers at the four corners of the hard edges
  4. Check slits 2 (KB1 JawUP) and slits 4 (DG2 Jaws) (skip slit 3, or KB1 JawDown, b/c they are not in use during the gas phase experiments), center them around the FEL
    1. Set markers on DG2 YAG camera
    2. Make sure we see hard edges from DG1 slits
    3. Then center KB1 and DG2 slits to the DG1 slits’ center: open all slits (~2mm), then check slits one by one (~0.3mm) by looking at their hard edges and center them to the reference markers
  5. Bring up and look at the SC1 YAG (cxi_sc1_inline camera), check slits 5 (DSB Jaws)
    1. Open all the slits except slits 1 (DG1 Jaws), make sure we see hard edges
    2. Close slits 1 (DG1 Jaws) even further if needed, set markers at the four corners
    3. Center slits 5 (DSB Jaws) to the DG1 reference makers
  6. Check the SC1 Slits mounted on piezo motors. Unlike other slits with centers and widths, we need to move individual motors in order to center the slits around the FEL. 
  7. Insert the prefocus lens, and align the lens (prefocus lens is one lens, not a stack) by looking at DG1_YAG with the lens aperture shadow. Transmission ~0.05 - 0.1 for a clear edge of the lens aperture on DG1 YAG.
    1. Beamline → Prefocus Lens → Click the button of the right photon energy to move the proper lens
    2. Use the Expert button to get the fine control
    3. The goal is to make the 4 curved corners in the center of the 4 slit blades, ~0.65mm for DG1 slits to see these corners clearly
  8. Insert the focusing lens stack, and align the lens stack by looking at the DG2_YAG with the lens aperture shadow.
    1. Insert DG2 YAG and remove DG1 YAG
      1. We can check again the beam alignment at DG2 YAG, tweak with HOMS or ACR pointing if necessary
    2. Close DG1 slits to 0.5mm, set transmission 1E-4 to 3E-4 (as low as possible, but need to see clear edges of the slits and lens aperture), insert DG2 lens PACK3 for timing or DG2 lens PACK2 for data taking
    3. Use the Expert button to get the fine control
  9. Check FEL go through the director hole and on SSC YAG, transmission up to ~5E-3, move DG2 YAG out
    1. cxi_sc3_inline camera
    2. Clear YAG position
      1. Ap Stand = -9
      2. PI3 Y = 48.0326 (as of 2022-06-11, this position can change if we changed the YAG padel)
    3. If no beam on SSC YAG
      1. Check if pinhole is not out, if so, move it out
      2. Try moving gas cell X & Y
      3. Try aligning Questar mirror (b/c sc1_inline mirror may be bumped)
    4. Once found FEL on SSC YAG, center laser in-coupling mirror X & Y around it
  10. Perform the gas cell alignment procedure if not done
  11. With the markers on SC3 YAG (from unfocused beam alignment of the gas cell)
    1. Close and fine align the DSB slits
      1. Move until cut, center them
    2. Close and fine align the SC1 piezo slits
      1. Move until cut, center them
  12. Make sure we don’t have the outer diffusive beam, one example of slits configuration of data taking mode:

    1. DG1 slits - 0.55, 0.55 mm

    2. KB1 Up slits - 0.4, 0.4 mm
    3. DG2 slits - 0.28, 0.28 mm
    4. DSB slits - 0.08, 0.09 mm
    5. SC1 piezo slits - 55, 40 um
  13. NOTE: DG1 slits gap should match pre-focus lens aperture (~0.5mm), and DG2 slits gap should match DG2 lens aperture (~0.3mm)
  14. If the beam looks not centered on DG2, with all the lens and slits, we should adjust the beam pointing (MR2L0_HOMS_PITCH) or undulator pointing, since our slits and lens are centered to DG1 slits